healthofcitizens

Colon cancer is the second-deadliest form of cancer after lung cancer. If recent messages about colon cancer screening have left you a little confused, that's understandable. In August, the American College of Physicians (ACP) released updated guidance for colon cancer screening that differs from other major organizations, including recommendations from the American Cancer Society (ACS) and the US Preventive Services Task force (USPSTF).

So, what do you need to know?

How does the advice differ?

First, please note that this advice applies only to people at average risk without a family history of colon cancer. If you have family history, or if other health issues put you at higher-than-average risk for colorectal cancer, talk to your doctor about the best course of action for you.

The main point of disagreement relates to the age at which people should start getting screened. The new ACP guidance says 50, while the other two organizations recommend 45. That earlier age is endorsed by the U.S. Multisociety Task Force on Colorectal Cancer. It's also endorsed by many physicians, including Harvard Medical School professor Dr. Andrew T. Chan, a gastroenterologist and director of epidemiology at Massachusetts General Hospital Cancer Center, who helps explain key facts below.

Why do experts suggest starting screening earlier?

"We're facing an unexplained and alarming increase in the incidence of colon cancer in people younger than 50," says Dr. Chan.

Overall, deaths from colon cancer dropped by 2% per year from 2011 to 2020. But that's not the case among people younger than 50. In that age group, deaths from colon cancer rose between 0.5% and 3% during the same time period, according to statistics published in 2023.

The rising rates of colon cancer in younger people are occurring in all racial and ethnic groups, with the steepest rises seen among Alaskan Natives and Native Americans. Overall, Blacks and African Americans are more likely to get and die from colon cancer than whites, and early-onset cases are higher in Black individuals than whites.

Efforts to encourage colon cancer screening began in the mid-1990s. Today, about 60% of adults over 50 follow the advice to receive a colonoscopy (described below) on a regular basis. This track record, while not perfect, likely explains the decline in deaths from colon cancer in older adults.

"I think that promoting earlier screening will help stem the rise in early-onset cases, at least for those in their 40s. We've also seen that earlier colonoscopies may be associated with lowering incidence of colon cancer even later in life, "says Dr. Chan.

What are the different screening tests for colon cancer?

The two most widely used screening tests are a standard colonoscopy and various stool-based tests.

Colonoscopy. For this test, a gastroenterologist or surgeon snakes a long, flexible tube with a camera on the end through your rectum and beyond to inspect the entire length of your colon. Considered the gold-standard test, this procedure can detect precancerous polyps called adenomas, and allow for their removal.

The test requires taking laxatives and drinking lots of fluids beforehand to clean all the fecal material (stool) out of your colon. Serious complications, which include perforation or bleeding, are rare, occurring in about three in 1,000 procedures. If no polyps are found, a repeat colonoscopy isn't recommended for another 10 years. If you have polyps, or your risk or symptoms change, this interval will be shorter.

Stool tests. The more worrisome colon polyps (adenomas) often shed tiny amounts of blood and abnormal DNA into the stool. This can be detected from samples you collect yourself at home.

• Two tests, the fecal occult blood test (FOBT) and fecal immunochemical test (FIT), check for blood. They require small stool samples that you put on a card or in a tube that's then mailed to a lab. These tests should be done every year.
• A third option, the FIT-DNA test, checks for both blood and abnormal DNA; it's usually repeated every three years.

Additionally, the guidelines from the American College of Physicians suggest another option: flexible sigmoidoscopy, which inspects only the lower part of the colon, once every 10 years, combined with a fecal FIT testing every two years. However, doctors in the United States rarely order sigmoidoscopy today.

If flexible sigmoidoscopy or any of these stool tests show evidence of a problem, a colonoscopy is needed to check for adenomas or cancer.

Why might stool-based screening make sense for younger adults?

Colonoscopy isn't necessarily the best initial screening test for everyone, says Dr. Chan. That's especially true for younger people, mainly because it's time-consuming and inconvenient.

"Maybe you just can't find time in your schedule or are worried about having a colonoscopy," he says. If that's the case, a stool-based test — which is noninvasive and takes very little time — is an appropriate option.

"The worst option is not doing anything, because early detection and treatment can prevent deaths," he says.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

In parts of the United States and Canada, warming temperatures driven by climate change may be contributing to a rise in tick-borne illnesses. Ticks are now thriving in a wider geographic range, and appearing earlier and sticking around later in the shoulder seasons of spring and fall. That means we need to stay vigilant about protecting ourselves against ticks that cause Lyme disease and other illnesses — even during winter months in many warmer states and provinces.

Here’s a timely reminder about why preventing Lyme disease is important, and a refresher on steps you can take to avoid tick bites.

What are the symptoms of Lyme disease?

Lyme disease is best known for its classic symptom, a bull’s-eye red rash that appears after a bite from an infected tick (scroll down to see photos of classic and non-classic rashes). However, 20% to 30% of people do not develop a rash. And a rash can be easy to miss because ticks tend to bite in dark body folds such as the groin, armpit, behind the ears, or on the scalp. Some people have flulike symptoms such as a headache, fever, chills, fatigue, and aching joints. So if you notice a rash or have these symptoms, call your doctor for advice. At this stage, prompt antibiotic treatment can wipe out the bacterial infection.

When people don’t receive treatment because they didn’t see the rash or didn’t have other early symptoms, the bacteria can spread to different parts of the body. Not only can the bacteria itself cause problems, but the body’s immune system can over-respond to the infection. Either process, or sometimes both, may harm joints, the heart, and/or the nervous system. And some people treated for any stage of Lyme disease develop post-Lyme disease syndrome, which can cause a range of debilitating symptoms that include fatigue, brain fog, and depression.

How to avoid getting Lyme disease

Preventing tick bites is the best way to avoid Lyme disease and other tick-borne illnesses. Blacklegged ticks (also called deer ticks) may be infected with the bacteria that causes Lyme disease. If you live in one of the areas where the incidence of Lyme disease is high, these steps can help.

Know where ticks are likely lurking. Ticks usually crawl up from leaves or blades of grass on the ground to the legs. So be extra careful when walking through fields or meadows and on hikes where you may brush up against bushes, leaves, or trees. Try to walk on well-cleared paths.

Wear protective clothing. Long pants tucked into socks is the best way to keep ticks from crawling up under the pant leg. Lighter-colored clothing can make ticks easier to see.

Use repellents. You can buy clothing that’s pretreated with the insecticide permethrin (which repels ticks). Or you can spray your own clothes and shoes; just be sure to follow the directions carefully. On all exposed skin, use a product that contains DEET, picaridin, oil of lemon eucalyptus (OLE), IR3535, para-menthane-diol (PMD), or 2-undecanone. This search tool from the EPA can help you find a product best suited for your needs. Pay attention to the concentration of active ingredients: for example, at least 20% but not more than 50% with DEET; between 5% to 20% with picaridin; and 10% to 30% with oil of lemon eucalyptus. Many products come in pump spray bottles or as sticks or wipes, which may make them easier to apply where needed.

Get a tick check. After spending time in tick-infested areas, ask a partner to check you for ticks in areas on your body that you can’t see very well. The common bite areas are the back of the knee, the groin, under the arms, under the breasts in women, behind the ears, and at the back of the neck. The tick species that transmits Lyme disease is about the size of a sesame seed. Note that a tick has to be attached to your skin for 24 to 36 hours for it to transmit enough bacteria to give you the disease.

For more information about preventing Lyme disease or living with it, visit the Harvard Health Publishing Lyme Wellness Initiative.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Want your child to grow up healthy, happy, smart, capable, and resilient? Play with them. Infants and toddlers thrive on playful games that change as they grow.

Why does play matter during the first few years of life?

More than a million new nerve connections are made in the brain in the first few years of life. And pruning of these neural connections makes them more efficient. These processes literally build the brain and help guide how it functions for the rest of that child’s life. While biology — particularly genetics — affects this, so does a child’s environment and experiences.

Babies and children thrive with responsive caregiving. Serve and return, a term used by the Harvard Center on the Developing Child, describes this well: back-and-forth interactions, in which the child and caregiver react to and interact with each other in a loving, nurturing way, are the building blocks of a healthy brain and a happy child, who will have a better chance of growing into a healthy, happy, competent, and successful adult.

Play is one of the best ways to do responsive caregiving. To maximize the benefits of play:

• Bring your full attention. Put the phone down, don’t multitask.
• Be reciprocal. That’s the “serve and return” part. Even little babies can interact with their caregivers, and that’s what you want to encourage. It doesn’t have to be reciprocal in an equal way — you might be talking in sentences while your baby is just smiling or cooing — but the idea is to build responsiveness into the play.
• Be attuned to developmental stages. That way your child can fully engage — and you can encourage their development as well.

Great games to play with infants: 6 to 9 months

The Center for the Developing Child has some great ideas and handouts for parents about specific games to play with their children at different ages.

6-month-olds and 9-month-olds are learning imitation and other building blocks of language. They are also starting to learn movement and explore the world around them.

Here are some play ideas for this age group:

• Play peek-a-boo or patty-cake.
• Play games of hiding toys under a blanket or another toy, and then “find” them, or let the baby find them.
• Have back-and-forth conversations. The baby’s contribution might just be a “ma” or “ba” sound. You can make the same sound back, or pretend that your baby is saying something (“You don’t say! Really? Tell me more!”).
• Play imitation games: if your baby sticks out their tongue, you do it too, for example. Older babies will start to be able to imitate things like clapping or banging, and love when grownups do that with them.
• Sing songs that involve movement, like “Itsy Bitsy Spider” or “Trot, Trot to Boston” with words and motions.
• Play simple games with objects, like putting toys into a bucket and taking them out, or dropping them and saying “boom!”

Great games to play with toddlers

Between 12 months and 18 months, young toddlers are gaining more language and movement skills, and love to imitate. You can:

• Play with blocks, building simple things and knocking them down together.
• Do imaginative play with dolls or stuffed animals, or pretend phone calls.
• Use pillows and blankets to build little forts and places to climb and play.
• Play some rudimentary hide-and-seek, like hiding yourself under a blanket next to the baby.
• Continue singing songs that involve movement and interaction, like “If You’re Happy And You Know It.”
• Go on outings and explore the world together. Even just going to the grocery store can be an adventure for a baby. Narrate everything. Don’t worry about using words your baby doesn’t understand; eventually they will, and hearing lots of different words is good for them.

Older toddlers, who are 2 or 3 years old, are able to do more complicated versions of these games. They can do matching, sorting, and counting games, as well as imitation and movement games like “follow the leader” (you can get quite creative and silly with that one).

As much as you can, give yourself over to play and have fun. Work and chores can wait, or you can actually involve young children in chores, making that more fun for both of you. Checking social media can definitely wait.

Playing with your child is an investment in your child’s future — and a great way to build your relationship and make both of you happy.

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

When preschoolers are melting down or teens are slamming doors, parents face two difficult tasks: keeping themselves composed and supporting their kids’ ability to self-soothe while building skills to handle future challenges.

These abilities are at the heart of co-regulation, a parenting tool that requires patience and practice. But what exactly is involved, and how does it help support children and teens wrestling with big emotions?

What is co-regulation?

“Co-regulation is a supportive, interactive, and dynamic process,” says Lauren Marchette, a child, adolescent, and family psychologist and a lecturer in psychiatry at Harvard Medical School.

Through warm and responsive interactions, caregivers help young people learn better ways to regulate their emotions during the inevitable upsets and challenges of life. “At its heart, co-regulation is connecting with a child who’s in distress and being able to evaluate what that child needs in the moment to help calm themselves.”

But before a parent or trusted adult can help a child, they need to understand — and possibly expand — their own emotional skills and limitations. Emotions are often contagious, whether a person is upset or sharing a sense of calm.

“The tricky part of co-regulation is that adults have to recognize how they’re feeling and be able to regulate their own emotions in difficult moments so they can help children to gain these same skills,” Marchette says. “But this will be so important for kids to develop healthy relationships over time, and affects how people do in school, work, and life in general.”

How does building emotional skills help children and teens?

As children grow up, they learn different skills — how to build a block tower, play a sport, or solve a math equation. They also learn emotional skills: how to recognize and handle feelings of anger or anxiety, for example.

Known as self-regulation, such emotional skills are truly the basis of wellness in life, Marchette says. By consistently practicing co-regulation, parents and other trusted adults foster self-regulation skills in kids.

The list of self-regulation skills is wide-ranging, involving

• emotional awareness and literacy, including the ability to identify emotions
• emotional regulation skills such as self-soothing
• perspective-taking, or the ability to "walk in another’s shoes”
• social skills such as taking turns and practicing patience
• paying attention and remaining focused when needed
• problem-solving
• thinking flexibly
• time management skills
• goal-setting.

What are the potential benefits of co-regulation?

Co-regulation enables kids to eventually learn to

• handle stress
• resist immediate gratification
• avoid hasty, ill-informed decisions
• make and stick to plans
• solve problems
• adapt to challenges
• take healthy risks.

Some research suggests that having better self-regulation skills is linked to more positive outcomes in life, such as higher income and lower rates of substance use and violence.

Who might especially benefit from co-regulation?

Everyone wins when kids are better able to navigate frustrations and manage their reactions to their thoughts and feelings. Parents, teachers, coaches, guidance counselors, mentors, and other adults who interact closely with children also stand to benefit.

As for kids themselves, it’s hard to think of any whose lives won’t be improved by adults who have invested themselves in practicing co-regulation, Marchette says.

But practicing co-regulation skills with certain children and adolescents — including those whose families are experiencing economic hardship, substance abuse, divorce, or other distressing situations — can be especially important.

Is there evidence that co-regulation works?

“While co-regulation is built upon a solid theoretical framework, not many studies have delved into its effectiveness — at least across all age groups,” Marchette says. “Research that does focuses mainly on infants and preschoolers.”

“Much less is known about how co-regulation interventions work for older youth,” she says. “The research is trying to catch up to what we know from years of clinical experience.”

How can a parent coach a child through co-regulation?

Co-regulation doesn’t stand alone as a skill. It relies on fostering a warm, responsive relationship with children, providing structure, and setting limits. “Children benefit from consistent, predictable routines with clear expectations and consequences,” Marchette says.

When a child begins experiencing big emotions, a co-regulation response will look different depending on the child and circumstances. But the steps to take are similar.

“First, the parent needs to pause and self-regulate their own emotions, such as by taking a deep breath,” Marchette explains. “The next steps are validating the child’s feelings, observing the child’s response, and then deciding how to respond next, including verbally and nonverbally, such as with a touch.”

Marchette offers an example based on her own practice: 12-year-old “Eric” is tackling a writing assignment in his bedroom when his mother suddenly hears loud noises. She walks to his door and finds him throwing a stapler, notebook, and container of pens off his desk. “What’s wrong with me?” he yells. “I suck at writing and I hate school!” Then Eric puts his head down on his desk.

The sixth grader’s mom knows he needs help calming down, so she pauses and takes a deep breath. Then she walks over and whispers his name, placing her hand on his shoulder. After more silence, Eric gradually starts sitting up in his chair. “I can tell how frustrated you are with this assignment,” she says to him, validating his feelings. “It must be a really challenging one.”

Eric’s mother knows he needs a break after he mutters, “I can’t do it.” She suggests a getting a glass of ice-cold water, and Eric glumly follows her to the kitchen. After the break, they can re-evaluate if Eric is ready to return to his homework or needs further coping strategies — like a walk outside or a round of jumping jacks — to get his frustration out.

What resources can help parents practice co-regulation?

The Administration for Children and Families offers a free Co-Regulation in Action video series. And some therapists — especially those who specialize in behavioral parent training or cognitive behavioral therapy — can help parents who feel their skills need a boost.

It’s worth noting that it can be hard to have sufficient resources — emotional, financial, and other supports — to practice co-regulation consistently. Those who wish to try should give themselves some grace as they learn the process. “Even parents who are thinking their own self-regulation skills aren’t where they want them to be should realize this is a muscle they can strengthen,” Marchette says. “It’s important to have that growth mindset.”

About the Author

Maureen Salamon, Executive Editor, Harvard Women's Health Watch

Maureen Salamon is executive editor of Harvard Women’s Health Watch. She began her career as a newspaper reporter and later covered health and medicine for a wide variety of websites, magazines, and hospitals. Her work has … See Full Bio View all posts by Maureen Salamon

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

You probably know that you have a thyroid gland. Perhaps you or someone you know has had thyroid tests or a thyroid disorder such as hypothyroidism.

But did you know you also have a parathyroid gland? It’s true — in fact, most people have four of them, even though one would suffice.

Where are the parathyroid glands?

From the name, you might assume the role of the parathyroid glands is related to that of the thyroid gland. Well, you’d be wrong. The name comes solely from their location: they sit just behind the thyroid gland: two on the right side, two on the left.

The parathyroid glands are small (the size of peas), and can weigh less than a thousandth of an ounce each. Although it’s normal to have four parathyroid glands, about 13% of people have fewer and 5% have more. And some people have parathyroid glands in other locations, such as alongside the esophagus or in the chest. This variation rarely matters, unless surgery is necessary to remove one or more of them.

What do the parathyroid glands do?

Logically enough, parathyroid glands make parathyroid hormone (PTH). And what does PTH do? It has several functions, including:

• Regulating calcium: Calcium is a mineral with many essential roles throughout the body, such as maintaining bone strength, allowing nerves and muscles to function normally, and making sure blood clots as it should. Higher levels of PTH lead to higher calcium levels in the blood through actions on the kidneys and bones.
• Regulating phosphorus: Among other roles, this mineral is a key component of our DNA, bones, and teeth. Phosphorus activates essential enzymes throughout the body, including enzymes necessary for cell reproduction and survival. It also helps with nerve and muscle function.
• Regulating vitamin D: This vitamin is actually a hormone that helps maintain normal levels of calcium throughout the body, by controlling how much gets absorbed from food in the intestinal tract and how much is lost by the kidneys in your urine. Remember PTH? Well, PTH regulates production of the enzyme that converts inactive vitamin D to an active form that helps your gut absorb calcium and reduces the loss of calcium in urine.

PTH released by the parathyroid glands helps keep each of these nutrients in balance. For example, if your blood calcium level falls, your parathyroid glands make more PTH. Higher amounts of PTH prompt bones to release stored calcium into the bloodstream, and also signal the kidneys to pull back on the amount of calcium lost through urine.

What if your blood calcium level rises? Then the parathyroid glands make less PTH, which helps to correct the blood calcium level.

Which diseases involve the parathyroid glands?

The most common are:

• Hyperparathyroidism: This is a condition in which the parathyroid glands make more than the normal amount of PTH. This can be due to a benign or cancerous tumor on a single gland, or due to multiple glands becoming overactive. Or it may be due to some other trigger, such as a low level of calcium in the blood, inadequate vitamin D levels, or kidney failure. When there’s too much PTH, blood calcium levels can become dangerously high and phosphorus levels fall. Surgery may be recommended to remove the overactive gland or glands.
• Hypoparathyroidism: This rare condition is diagnosed when less than the normal amount of PTH is produced. The most common causes are prior neck surgery or radiation, autoimmune disease, or low magnesium levels.
• Parathyroid cancer: Risk factors for parathyroid cancer include certain genetic diseases and prior radiation to the neck.

Why do we rarely hear about the parathyroid glands?

The reason is that most of the time they do their job without fuss or fanfare. Although disorders of the parathyroid glands are not rare, they are just uncommon enough that most people will never hear about them. I think of the parathyroid glands as one of many parts of our bodies that play a huge role in our health, but go unappreciated because they are so good at what they do.

Many other quiet heroes, including the thymus gland, serve as testaments to the remarkable design and function of the human body. Then again, I can think of a few body parts that could be considered expendable.

The bottom line

I hope it’s comforting to know that your amazing parathyroid glands are keeping tabs on your calcium levels and helping your bones, nerves, muscles, and other organs to function normally.

Ounce for ounce, the parathyroid glands may be the most important glands you’d never heard of. Until now.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Concussion is one of the most common injuries to the brain, affecting about two million children and teens every year. It is a particular kind of injury that happens when a blow to the head or somewhere else on the body makes the brain move back and forth within the skull.

It’s possible to get a concussion after what might seem like a minor injury, like a forceful push from behind, or a collision between two players in a football or soccer game.

What are the signs and symptoms of concussion?

Because the injury may not seem that significant from the outside, it’s important to know the symptoms of a concussion. There are many different possible symptoms, including

• passing out (this could be a sign of a more serious brain injury)
• headache
• dizziness
• changes in vision
• feeling bothered by light or noise
• confusion or feeling disoriented
• memory problems (such as difficulty remembering details of the injury) or difficulty concentrating
• balance or coordination problems
• mood changes.

Some of these are visible to others and some are felt by the person with the concussion. That’s why it’s important to know the signs and to ask all the right questions of a child who has had an injury.

Sometimes the symptoms might not be apparent right away, but show up in the days following the injury. The CDC’s Heads Up website has lots of great information about how to recognize a concussion.

How can further harm to the brain be avoided?

The main reason it’s important to recognize a possible concussion early is that the worst thing you can do after getting a concussion is get another one. The brain is vulnerable after a concussion; if it is injured again, the symptoms can be longer lasting — or even permanent, as in cases of chronic traumatic encephalopathy (CTE), a condition that has been seen in football players and others who have repeated head injuries.

If there is a chance that a child has had a concussion during a sports competition, they must stop playing — and get medical attention. It’s important to get medical attention any time there is concern about a possible concussion, both to be sure there isn’t a more serious brain injury, and to do a good assessment of the symptoms, so that they can be monitored over time. There are some screening questionnaires that are used by doctors that can be used again in the days and weeks after the concussion to see how the child is improving.

What helps children recover after a concussion?

Experts have struggled with figuring out how to protect the brain after a concussion. For a long time, the recommendation was to rest and do very little at all. This meant not doing any exercise, not going to school, not even reading or watching television. As symptoms improved, the restrictions were lifted gradually.

Over time, though, research showed that not only was this much rest not necessary, it was counterproductive. It turns out that getting kids back into their daily lives, and back into being active, is safe and leads to quicker recovery. Experts still recommend rest and then moving gradually back into activities, but the guidelines are no longer as strict as they once were.

One important note: A medical professional should guide decisions to move from rest to light activity, and then gradually from there to moderate and then regular activities based on how the child is doing. This step-by-step process may extend for days, weeks, or longer, depending on what the child needs. Parents, coaches, and schools can help support a child or teen as they return to school and return to activities and sports.

Some children will be able to get back into regular activities quickly. But for others it can take weeks or even months. Schools and sports trainers should work with children to support them in their recovery. Some children develop post-concussive syndromes with headache, fatigue, and other symptoms. This is rare but can be very disabling.

How can parents help prevent concussions?

It's not always possible to prevent concussions, but there are things that parents can do:

• Be sure that children use seat belts and other appropriate restraints in the car.
• Have clear safety rules and supervise children when they are playing, especially if they are riding bikes or climbing in trees or on play structures.
• Since at least half of concussions happen during sports, it’s important that teams and coaches follow safety rules. Coaches should teach techniques and skills to avoid dangerous collisions and other injuries. Talk to your child’s coaches about what they are doing to keep players safe. While helmets can prevent many head injuries, they don’t prevent concussions.

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

A bird flu strain that began circulating in 2020 continues to evolve globally and locally within the United States. If you’re wondering what this means, understanding the basics — what bird flu is, how it spreads, whether foods are safe, and prevention tips — can help. More information will come in as scientists learn more, so stay tuned.

1. What is bird flu and how does it spread?

Bird flu, or avian flu, is a naturally occurring illness. Just as certain flu viruses spread among humans, Type A influenza viruses often spread among wild birds. The strain of virus circulating now is H5N1, named for two proteins on its surface.

Avian flu infections are highly contagious. Infection often spreads first among wild water birds, such as ducks, geese, and gulls, and shore birds, such as plovers and sandpipers. The viruses are carried in their intestines and respiratory tract and shed in saliva, mucus, and feces. Wild birds can easily infect domestic poultry, such as chickens, turkeys, and ducks.

Some bird species, including ducks, may carry and spread infection without appearing sick. Domestic flocks are more likely to sicken and possibly die from bird flus. However, not all avian flu viruses are equally harmful:

• Low pathogenic avian influenza (LPAI) may cause no signs of illness, or signs of mild illness like fewer eggs or ruffled feathers in domestic poultry.
• Highly pathogenic avian influenza (HPAI) causes more severe illness and high rates of death in infected poultry. The current H5N1 virus is considered an HPAI.

2. Can humans get bird flu?

Yes, though this doesn’t usually happen.

When flu viruses mutate, they may be able to move from their original hosts — birds in this case — to humans and other animals. At this writing, two cases of bird flu in humans have been reported in the US since 2022.

The virus may be introduced into the body through the eyes, nose, or mouth. For example, a person may inhale viral particles in the air (droplets, tiny aerosolized particles, or possibly in dust). Or they might touch a surface contaminated by the virus, then touch their eyes or nose. Bird flu in humans typically causes symptoms similar to seasonal flu, such as fever, runny nose, and body aches.

3. Which animals have been affected by bird flu?

A surprisingly long list of animals affected by the current H5NI bird flu infection includes:

• wild birds, chickens, ducks, geese, and other domestic and commercial poultry in 48 states and more than 500 countries
• livestock, such as dairy cows in nine states at this writing, and other farm animals
• marine animals, such as seals, sea lions, and even dolphins
• wild animals, such as foxes, skunks, and racoons, and some domestic animals, such as farm cats.

4. Why are experts concerned about this bird flu outbreak?

It might seem odd that there’s been so much concern and news coverage about bird flu lately. After all, bird flu has been around for many years. We’ve long known it sometimes infects nonbird animal species, including humans.

But the current outbreak is unique and worrisome for several reasons:

• Fast, far-reaching spread. The virus has been found throughout the US, Europe, the Middle East, Southeast Asia, multiple sub-Saharan African countries, and even Antarctica.
• Many species have been infected. Previously uninfected species have been affected, including animals in our food supply.
• Economic impact. If large numbers of beef and dairy cows and chickens sicken or must be culled (killed) to contain outbreaks, this could have a major economic impact on farmers, agriculture businesses, and affected countries’ economies. This could also mean higher prices at the grocery store.
• Opportunities for exposure. Though only two human infections were reported in the US in recent years — both in people working with animals — the more exposure humans have to bird flu, the more chances the virus has to develop mutations that allow easier spread to humans.
• Potential for fatalities. Severe strains of bird flu have led to H5N1 infections in nearly 900 people in 23 countries since 2003. More than half of these reported cases were fatal. Keep in mind that the math isn’t straightforward. It’s likely that many more cases of bird flu in humans occurred, yet people experiencing few or no symptoms or those not tested weren’t counted, so lethality is likely overestimated.
• New mutations. It’s rare, but possible: If this H5N1 bird flu develops mutations that enable efficient person-to-person spread, bird flu could become the next human pandemic.

5. Are milk, beef, chicken, and the rest of our food supply safe?

Public health officials emphasize that the food supply is safe.

But concern has understandably run high since the discovery that this outbreak has spread from birds to dairy cows for the first time. More alarming? A study found fragments of bird flu DNA — which is not the same as live virus — in 20% of commercially available milk in the US.

So far, there’s been no indication that bird flu found in pasteurized milk, beef, or other common foods can cause human illness. Even if live bird flu virus got into the milk supply, studies show that routine pasteurization would kill it. Initial tests did not find the virus in ground beef.

Of course, if you are particularly concerned, you could avoid foods and beverages that come from animals affected by bird flu. For example, you could switch to oat milk or almond milk, even though there’s no convincing scientific justification to do so now.

6. What if you have pets or work with animals?

Bird flu rarely spreads to pets. While that’s good news, your pets could have exposure to animals infected with bird flu, such as through eating or playing with a dead bird. So, it’s safest to limit your pet’s opportunities to interact with potentially infected animals.

If you work with animals, especially birds or livestock, or hunt, the Centers for Disease Control and Prevention (CDC) recommends precautions to minimize your exposure to bird flu.

7. What else can you do to stay safe?

The CDC recommends everyone take steps to avoid exposure to bird flu, including:

• Avoid contact with sick or dead animals and keep pets away from them.
• Avoid animal feces that may be contaminated by birds or bird droppings, as might be common on a farm.
• Do not prepare or eat raw or undercooked food.
• Do not drink raw (unpasteurized) milk or eat raw milk cheese or raw or undercooked foods from animals suspected of having bird flu infection.
• Wear personal protective equipment (PPE), such as safety goggles, gloves, and an N95 face mask, when working near sick or dead animals or their feces.

Right now, available evidence doesn’t support more dramatic preventive measures, such as switching to an all-plant diet.

8. Is there any good news about bird flu?

Despite all the worrisome news about bird flu, this recent outbreak may wind up posing little threat to human health. Virus strains may mutate to spread less efficiently or to be less deadly. Efforts are underway to contain the spread of bird flu to humans, including removing sick or exposed animals from the food supply and increased testing of dairy cattle before transport across state lines.

And there is other encouraging news:

• Some birds appear to be developing immunity to the virus. This could reduce the chances of continued spread between birds and other animals.
• Developing a vaccine to protect cattle from bird flu may be possible (though it’s unclear if this approach will be successful).
• If spread to humans does occur, genetic tests suggest available antiviral medicines could help treat people.
• So far, human-to-human transmission has not been detected. That makes it less likely that the H5N1 bird flu will become the next pandemic.
• And if human infections with bird flu did become more common, researchers are working on human vaccines against bird flu using virus strains that match well with those causing the current outbreak.

9. How worried should you be about bird flu?

Though there’s much we don’t know, this much seems certain: bird flu will continue to change and pose challenges for farmers and health experts to stay ahead of it. So far, public health experts believe that bird flu poses little health risk to the general public.

So, it’s not time to panic about bird flu. But it is a good idea to take common sense steps to avoid exposure and stay current on related news.

For updated information in the US, check the CDC website .

About the Authors

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Francesca Coltrera, Editor, Harvard Health Blog

Francesca Coltrera is editor of the Harvard Health Blog, and a senior content writer and editor for Harvard Health Publishing. She is an award-winning medical writer and co-author of Living Through Breast Cancer and The Breast … See Full Bio View all posts by Francesca Coltrera

About the Reviewer

John Ross, MD, FIDSA, Contributor; Editorial Advisory Board Member, Harvard Health Publishing

Dr. John Ross is an assistant professor of medicine at Harvard Medical School. He is board certified in internal medicine and infectious diseases, and practices hospital medicine at Brigham and Women’s Hospital. He is the author … See Full Bio View all posts by John Ross, MD, FIDSA

Trees enhance life in a multitude of ways. They combat climate change by reducing greenhouse gases in the atmosphere. They muffle sound pollution and reduce air pollution, drawing in carbon dioxide and releasing oxygen. When rain pours from the skies, trees decrease stormwater runoff, preventing flooding and soil erosion. They also provide valuable habitats to support biodiversity in insects, birds, and other animals, and microorganisms. The list goes on.

Equally important is accumulating evidence that simply spending time around trees and green spaces uplifts our health and mood. Below are a few of the biggest benefits we reap.

Keeping it cool: Trees help prevent heat-related illness

Climate change is causing rising temperatures and more heat waves across the US. These effects are worse for those who live in neighborhoods known as urban heat islands, where asphalt and concrete soak up heat during the day and continue to radiate it at night. Temperatures can reach 7° F hotter than suburban, rural, or simply wealthier and leafier neighborhoods.

Trees and their leafy canopy provide shade that helps to prevent urban heat islands. What does that mean for individuals? It translates to fewer heat-related health illnesses, which strike outdoor workers and younger, older, and medically vulnerable people more often. A study published in The Lancet calculated that increasing tree canopy to 30% coverage in 93 European cities could prevent an estimated four in 10 premature heat-related deaths in adults in those cities.

How trees help children: Better mood, behavior, attention, and more

Spending more time in nature has been linked with better health outcomes like lower blood pressure, better sleep, and improvement in many chronic conditions in adults. These findings are prompting a growing interest in forest therapy, a guided outdoor healing practice that leads to overall improved well-being. But what’s also remarkable are the varied benefits of trees and nature for children.

One study of children 4 to 6 years old found that those who lived close to green space demonstrated less hyperactive behavior and scored more highly on attention and visual memory testing measures compared with children who did not.

Just seeing trees can have mental health benefits. In Michigan, a study of children between the ages of 7 and 9 demonstrated that students who could see trees from their school windows had fewer behavioral problems than those with limited views.

In Finland, researchers modified daycare outdoor playscape environments to mimic the forest undergrowth. These daycares were compared to control standard daycares and nature-oriented daycares where children made daily visits to nearby forests. At the end of 28 days, the children in the daycares with modified forest undergrowth playscapes harbored a healthier microbiome and had improved markers of their immune systems as compared to their counterparts.

How green space helps communities

Having green space in neighborhoods also does a lot to enrich the well-being of communities. A randomized trial in a US city planted and maintained grass and trees in previously vacant lots. Researchers then compared these green spaces to lots that were left alone.

In neighborhoods below the poverty line, there was a reduction in crime for areas with greened lots compared to untouched vacant lots. Meanwhile, residents who lived near lots that were greened reported feeling safer and increased their use of the outside space for relaxing and socializing.

How can you help?

Unfortunately, urban tree canopy cover has been declining over the years. To counter this decline, many towns and nonprofit organizations have programs that provide trees for planting.

A few examples in Massachusetts are Canopy Crew in Cambridge and Speak for the Trees in Boston. (Speak for the Trees also offers helpful information on selecting and caring for trees). Neighborhood Forest provides trees for schools and other youth organizations across the US. Look for a program near you!

Planting trees native to your region will better suit the local conditions, wildlife, and ecosystem. Contact your regional Native Plant Society for more information and guidance. If you are worried about seasonal allergies from tree pollen, many tree organizations or certified arborists can give you guidance on the best native tree selections.

If planting trees is not for you but you are interested in contributing to the mission, consider donating to organizations that support reforestation, like The Canopy Project and the Arbor Day Foundation.

About the Author

Wynne Armand, MD, Contributor

Dr. Wynne Armand is a physician at Massachusetts General Hospital (MGH), where she provides primary care; an assistant professor in medicine at Harvard Medical School; and associate director of the MGH Center for the Environment and … See Full Bio View all posts by Wynne Armand, MD

Each year, more than 4.5 million dog bites occur in the United States. Despite what you might assume, most of these incidents don’t happen when an unfamiliar dog attacks someone in a park or another outdoor location. Instead, most dog bites are inflicted by a pet dog in a home.

Here’s advice for avoiding these upsetting and potentially serious injuries — and the steps you should take if you sustain a dog bite.

Why do dog bites happen?

Some dog bites happen by accident when people wrestle or play tug-of-war with their dog. But most of the time, dogs bite people as a reaction to feeling stressed, threatened, scared, or startled, according to the American Veterinary Medical Association (AVMA). More than half of dog bites occur in children, and they’re far more likely to be seriously injured than adults.

“People don’t always heed the behavioral signals that a dog is uncomfortable,” says Dr. Christopher Baugh, associate professor of emergency medicine at Harvard Medical School. For example, some dogs are highly territorial and will bark, growl, snap, and lunge if outsiders enter their space — whether that’s an apartment, yard, or crate. Or dogs may exhibit resource guarding, which shows up as anxious, aggressive behavior around food, toys, or beds.

“These situations can be high-risk, and children in particular have less awareness of that risk,” says Dr. Baugh, who has children and two mixed-breed rescue dogs, Harley and Roxi.

What can you do to prevent dog bites?

Any dog — even a sweet, cuddly dog — can bite if provoked, according to the AVMA. Never leave young children alone with a dog without adult supervision. And teach children to never disturb a dog while it’s eating, sleeping, or caring for puppies.

In a study of 321 facial dog bites treated at Harvard-affiliated Massachusetts General Hospital over a 20-year period, 88% of the bites were from known dogs. Most were in adults and occurred after playing with the dog, feeding the dog, and placing their face close to the dog. However, the hand (usually a person’s dominant hand) is probably the most common location for a dog bite in an adult, says Dr. Baugh.

Other tips from the CDC to prevent dog bites include the following:

• Always ask a dog’s owner if it’s okay to pet their dog, even if the dog appears friendly.
• Make sure the dog sees and sniffs you before reaching out to pet it.
• Don’t pet a dog that seems to be hiding, scared, sick, or angry.

What if an unfamiliar dog approaches you? Remain calm and still, avoiding eye contact with the dog. Stand with the side of your body facing the dog and say “no” or “go home” in firm, deep voice. Wait for the dog to retreat or move yourself slowly away.

What should you do if you’re bitten by a dog?

Clean the wound with mild soap and running water, then cover it with a clean bandage or cloth. Some online resources recommend applying an antibiotic ointment or cream. But these products are recommended only for people with clear evidence of an infection, such as redness, pus, pain, swelling, or warmth, according to the American Academy of Dermatology.

If the injury is serious — with a bite on the face, heavy bleeding, or a possible broken bone — go to the emergency room. That’s also a good idea if you’re bitten by an unknown or stray dog, in the rare event that you might need medicines to prevent rabies (rabies post-exposure prophylaxis).

“Often, people are shocked after being bit and will understandably focus all their attention on their wound,” says Dr. Baugh. The dog’s owner may check in to see if you’re okay, but then walk away. But you should get the person’s contact information and make sure the dog is vaccinated against rabies, he says.

Keep in mind that:

• Emergency rooms are often crowded with long waits, so an urgent care clinic is a good option if the injury doesn’t require immediate attention.
• Some wounds require stitches, ideally within 12 to 24 hours.
• The doctor may prescribe antibiotics to prevent possible infections, especially if you have health problems such as a weakened immune system or diabetes.
• You may also need a tetanus booster if you haven’t had one in the past 10 years. If your vaccine history isn’t available or you can’t remember, you’ll get a tetanus booster just in case.

What if a dog bite is less serious?

Let’s say you have a less serious bite from a family dog known to have a current rabies vaccine. Bites that don’t require stitches can be cleaned with mild soap and running water, then evaluated by your regular health care provider. They may tell you to simply monitor the wound for signs of infection.

“Doctors are trying to be more thoughtful about prescribing antibiotics and limit their use in low-risk situations, because overuse contributes to antibiotic resistance and exposes people to potential side effects without any benefit,” says Dr. Baugh.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Need a little motivation and structure to ramp up your walking routine? Want to wake up your workouts but not quite ready for a mud run? Consider trying a couch-to-5K program.

Dr. Adam Tenforde, medical director of the Spaulding National Running Center at Harvard-affiliated Spaulding Rehabilitation Network and a sports medicine physician at Mass General Brigham Sports Medicine, shares tips on what to know and do before lacing up your sneakers.

What is a couch-to-5K program?

These free or low-cost coaching plans are designed to help would-be runners train for a 5-kilometer race, which is about 3.1 miles. The programs are available online, or as apps or podcasts. They typically feature timed walking and running intervals that gradually phase out the walking over a period of about nine weeks.

Why try a couch-to-5K program?

“One purpose of a couch-to-5K program is to give you time to acclimate and start to enjoy the benefits of running and the sense of accomplishment of completing a distance safely,” says Dr. Tenforde. Running provides many cardiovascular benefits, such as lower blood pressure and a reduced cholesterol level, as well as an enhanced sense of well-being, he adds.

What’s more, adding even short bursts of running or other vigorous physical activity to a workout — a practice known as high-intensity interval training or HIIT — appears to help improve mental health, according to a study that pooled findings from 58 randomized trials of HIIT.

Are you ready to tackle a couch-to-5K?

Even though the couch-to-5K programs sound as though they’re geared for completely sedentary couch potatoes, that’s not necessarily true, Dr. Tenforde cautions. These programs often assume you can walk continuously for 30 minutes, which doesn’t apply to everyone.

For some people, an even easier, more gradual training regimen may be more appropriate. Also, keep in mind that you don’t have to run to do a 5K. Many of these races also encourage walkers to participate as well. You’ll still reap the other rewards from committing to a race, such as being more challenged and motivated — and possibly more connected to your community. Many charitable “fun runs” benefit local schools or needy families. Some are in memory of people affected by illness or tragedy. Visit Running in the USA to find 5K races near you.

What to do before you start

If you’re planning to walk or run your first 5K, get your doctor’s approval before you start training. That’s especially important if you have heart disease or are at risk for it.

Comfortable walking or running shoes are a wise investment. Shoes that are too old or too tight in the toe box can cause or aggravate a bunion, a bony bump at the outer base of the big toe. Despite suggestions that people with flat feet or high arches need specific types of shoes, studies have found that neutral shoes (designed for average feet) work well for almost everyone. Walk or jog around the store when you try them on to make sure they feel good and fit properly.

You don’t need to buy special clothes; regular sweat pants or comfortable shorts and a t-shirt will suffice. Women should consider getting a supportive sports bra, however.

Go slow and steady when training

• Always include a warm-up and cool-down — a few minutes of slow walking or jogging — with every exercise session.
• If you haven’t been exercising regularly, start by walking just five or 10 minutes a day, three days a week. Or, if you’re already a regular walker, add some short stints of jogging to each walking session.
• Gradually add minutes and days over the following four to six weeks.
• Once you’re up to 30 minutes a day, check how far you’re traveling. Keep increasing your distance every week until you reach 5 kilometers. Then slowly phase in more jogging and less walking over your route if you like.

Remember that you can always repeat a week. You’re less likely to sustain an injury if you make slow, steady progress. Pay close attention to your body and don’t push yourself too much, Dr. Tenforde advises. Former athletes who haven’t run in years may think they can pick up where they left off, but that’s not a smart move — they should also start low and go slow.

For a good couch-to-5K guide, try this beginner’s program from the United Kingdom’s National Health Service.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD