Month: October 2022

There are certain things our bodies do so often and so automatically that we barely notice them. Yawning, growling stomachs, and runny noses are good examples. Each is a universal part of our daily human experience.

But did you ever wonder why? Below are a few things we know and a few we suspect.

Why do you yawn?

Perhaps you associate yawning only with being tired or bored. While we don’t know exactly why people yawn, there’s no shortage of theories. Yawning may

• stretch out our lungs and nearby tissues, preventing tiny airways in the lungs from collapsing
• distribute a chemical called surfactant, a gooey liquid that coats the tiny air pockets in the lungs and helps keep them open
• help prepare our bodies for transitions between wakefulness and rest: For example, yawning often occurs after a period of relaxation and when awakening from sleep. And it may serve as an internal signal that it’s time to sleep, or time to take a break from activities (such as driving).
• play a role in maintaining proper brain temperature: Our brain functions best within a narrow range of temperatures. Some experts believe yawning can help cool the brain through complex effects on nearby circulation and the sinuses.

It’s also unclear why yawning is contagious. In the animal kingdom, it’s common to see contagious yawning among members of a group, perhaps as a signal for collective behavior (such as moving from activity to rest).

Why does your stomach growl?

That rumbling in your stomach is known medically as borborygmi — an excellent Scrabble word if you have the right letters. We usually assume it reflects hunger. And it’s true that the experience of hunger can make itself heard in anticipation of a meal.

But your stomach may also growl after a meal, when the stomach and intestines propel liquids and food through the digestive tract. Stress can also trigger stomach rumbling.

What’s causing all that noise — and is it ever a problem? It may be due to gas moving around in response to muscular contractions of the intestinal walls. Occasionally, noises from the abdomen may be a sign of an intestinal infection or other trouble. If you’re experiencing other symptoms, such as pain or fever, check in with your doctor. But the vast majority of noises are harmless and a sign that your gut is working normally.

Why does your nose run?

Sometimes it can seem like your nose is running for no reason. But there are some well-known triggers, such as:

• Infection. When you have a cold, mucous membranes produce more mucus as part of your defense system: more mucous flowing out means fewer germs getting in.
• Allergies. Pollen, ragweed, or other triggers stimulate immune cells that produce histamine. Histamine opens up blood vessels just beneath the mucous membranes, and that leads to increased production and release of fluid and mucus. As with infection, this response may be helpful to dilute the offending trigger and rid it from the area.
• Cold, dry air. The inside surface of the nose is covered with mucous membranes that warm and humidify air well before it reaches the lungs. When you inhale dry, cold air through your nose, these membranes humidify the air by secreting water and mucus.
• Spicy foods. Spices like capsaicin act as an irritant to the sinuses and mucous membranes, which release fluid in response.

The bottom line

Some of the most common everyday human experiences are also some of the least understood. There are many other examples, of course: Why are we ticklish? What purpose do hiccups serve? What’s the deal with brain freeze? Perhaps topics for another day.

It may seem like a leap of faith, but it’s likely there are very good reasons for the way our bodies work — even when we don’t know what those reasons are.

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

In June, the FDA approved a new treatment for the most advanced type of prostate cancer. Patients who have this condition, which is called metastatic castration-resistant prostate cancer (mCRPC), have few therapeutic options, so the approval helps to fill an urgent need.

mCRPC sets in when the front-line hormonal therapies that doctors use first for treating metastatic prostate cancer stop working. These drugs limit the body’s production of testosterone, a hormone that fuels prostate cancer growth. If they are no longer effective, then doctors switch to a different class of drugs known as anti-androgens that further inhibit testosterone by blocking its cell receptor. One of those drugs is called enzalutamide.

The newly approved treatment combines enzalutamide with a second drug, talazoparib, that was already on the market for female cancer patients who test positive for BRCA mutations. These inherited gene defects boost risks for breast and ovarian cancer, but they can also elevate risks for prostate cancer in men. Indeed, an estimated 10% of men with metastatic prostate cancer are BRCA-positive.

Talazoparib inhibits a DNA-repair system called PARP that the tumor cells need to keep their own genes in working order. When PARP is blocked by treatment, the cancer cells will eventually die. Other PARP inhibitors, including olaparib and rucaparib, are already approved for advanced prostate cancer in BRCA-positive men.

During research leading to this latest approval, 399 men with mCRPC were randomly divided into two groups. One group received talazoparib plus enzalutamide; the other group was treated with enzalutamide plus placebo. The men averaged 70 years in age, and most of them had already been treated with chemotherapy and/or a different anti-androgen called abiraterone. All the men were positive for either BRCA mutations or defects affecting other DNA-repair genes.

What the study showed

Results from the still-unpublished study were presented at the 2023 American Society of Oncology Annual Meeting in June. After a median follow-up of roughly 17 months, the enzalutamide/talazoparib combination reduced the risk of death or visible signs of tumor progression by 55%.

Among the specific subgroup of BRCA-positive patients, “there was an 80% reduction in risk progression or death, which is enormous for these men and obviously very welcome,” said lead researcher Dr. Karim Fizazi, a professor at the University of Paris-Saclay in France.

Scientists had hoped that combining PARP inhibitors with anti-androgens would similarly benefit prostate cancer patients with no DNA-repair defects, but evidence from a different study by Dr. Fizazi and his colleagues shows they do not.

For that reason, the FDA approved the new combination only for mCRPC patients who test positive for mutations affecting DNA-repair genes. Dr. Fizazi and his colleagues are continuing to monitor the enrolled patients for improvements in other areas, such as overall survival, quality of life, and subsequent need for chemotherapy.

Dr. David Einstein, an assistant professor of medicine at Harvard Medical School and a medical oncologist at Beth Israel Deaconess Medical Center in Boston, says the evidence helps to confirm that PARP inhibitors have a role to play in genetically-selected men with mCRPC. Additional research is needed to assess if the observed benefits are “specific to the combination or just because access to PARP inhibition was provided at some point in the disease course,” he says.

“Genetic testing for BRCA, which originally targeted females, is now becoming mainstream for men with a family history of breast and ovarian cancers, as well as men with mCRPC regardless of family history,” says Dr. Marc B. Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center. “This is important, as it has implications for other family members and treatment choices alike. Also important to note is that where this study enrolled men who had already been treated with chemotherapy and/or abiraterone, future research will likely move the enzalutamide/talazoparib combination — or components of it — to earlier disease stages.”

About the Author

Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases

Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt

About the Reviewer

Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD

Picture this: you’re with friends in an unfamiliar forest using only a map and a compass to guide you to an upcoming checkpoint. There are no cell phones or GPS gadgets to help, just good old brainpower fueled by a sense of adventure as you wind through leafy trees and dappled sunlight.

This is not an excursion to a campsite or a treasure hunt. It’s a navigation sport called orienteering — a fun way to get outside, exercise, and maybe even help fight cognitive decline, according to a 2023 study.

What is orienteering?

Orienteering combines map and compass reading with exercise. Competitors (“orienteers”) race against a clock to reach checkpoints in outdoor settings that can range from city parks to remote areas with mountains, lakes, rivers, or snowy fields.

“You can go out in a group or on your own. You get a very detailed map and navigate your way to checkpoints that record your time electronically,” says Clinton Morse, national communications manager with Orienteering USA, the national governing body for the sport in the United States.

Because orienteers are racing the clock, they might run on trails, hike up hills, or scramble around boulders. That’s for foot-orienteering events. There are also orienteering events with courses geared for mountain biking, cross-country skiing, or canoeing.

How might orienteering affect thinking skills?

A small 2023 study published online in PLoS One found a potential link between orienteering and sharp thinking skills.

Researchers asked 158 healthy people, ages 18 to 87, about their health, activities, navigation abilities, and memory. About half of the participants had varying levels of orienteering experience. The other participants were physically active but weren’t orienteers.

Compared with study participants who didn’t engage in orienteering, those who were orienteers reported

• having better navigational processing skills (recognizing where objects were, and where participants were in relation to the objects)
• having better navigational memory skills (recalling routes and landmarks).

The study was observational — that is, not a true experiment — and thus didn’t prove that orienteering boosted people’s thinking skills. But the link might be plausible.

“Aerobic exercise releases chemicals in the brain that foster the growth of new brain cells. And when you use a map and connect it to landmarks, you stimulate growth between brain cells,” says Dr. Andrew Budson, lecturer in neurology at Harvard Medical School and chief of cognitive and behavioral neurology at VA Boston Healthcare System.

Where can you find orienteering opportunities?

There are about 70 orienteering clubs across the United States, and many more around the world (the sport is extremely popular in Europe). To find an orienteering event in your area, use the club finder tool offered by Orienteering USA.

How can you get started with orienteering?

People of all ages and athletic levels can take part, because orienteering courses vary from local parks to wilderness experiences. Costs are about $7 to $10 per person for local events, or $25 to $40 per person for national events, plus any travel and lodging expenses.

To make orienteering easy at first, Morse suggests going with a group and taking things slowly on a short novice course. “You don’t have to race,” he says. “Some people do this recreationally to enjoy the challenge of completing a course at their own pace.”

The trickiest part is learning to read the map. Morse’s advice:

• Turn the map as you change directions. Hold the map so that the direction you’re heading in is at the top of the page. For example, if the compass indicates that you’re heading south, turn the map upside down, so the south part is on top and easier to follow.
• Create a mental image of what the map is telling you. If there’s a fence along a field on the map, build a picture of it in your mind so you can recognize it when you see it, even if you haven’t been there before.

Tips for safe and enjoyable orienteering events:

• Dress appropriately. Wear comfortable clothes including long pants, good walking shoes, and a hat.
• Lather up. You’ll be outside for at least an hour, and you’ll need sunblock and possibly tick and bug spray depending on the terrain. Preventing tick bites that can lead to Lyme disease and other tick-borne illnesses is important in many locations.
• Bring some essentials. Pack water, a snack, sunblock, bug spray, and your phone. (Keep the phone turned off unless you need to call for help.)
• Use good judgment. Know that the shortest route on the map won’t always be the best, since it might take you up a hill or through thick vegetation. It might be better to go around those areas.

Once you learn the basics of orienteering, you can make it more physically challenging (and a better workout) by going faster and trying to beat your previous times, or by signing up for a more advanced course that’s longer and requires more exertion and speed.

And no matter which event you take part in, enjoy the adventure. “You’re not just following a path, you’re solving puzzles while being immersed in nature,” Morse says. “It’s a great way to experience the outdoors.”

About the Author

Heidi Godman, Executive Editor, Harvard Health Letter

Heidi Godman is the executive editor of the Harvard Health Letter. Before coming to the Health Letter, she was an award-winning television news anchor and medical reporter for 25 years. Heidi was named a journalism fellow … See Full Bio View all posts by Heidi Godman

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