Here Comes the Sun (and the Heat)

A thermometer shows high temperatures against the sun, a blue sky and a few white clouds.

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Summer is in full swing, and with a near-peak number of daylight hours, chances are good that there is still plenty of light left to enjoy once your workday is done. Before you get outside and bask in the sun and heat, check out these I Spy posts that explain how your body responds to hot weather and provide tips to help you stay safe this summer:

Have a safe, sunny and fun summer!

Erica Roth

Relieve Stress and Anxiety with Exercise in the New Year

Group of Young People Exercising in a Gym

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If getting more exercise is one of your New Year’s resolutions, here is another reason to stick with it: daily exercise—which is known to lower blood pressure—has also been shown to reduce stress and anxiety. I am not the first to notice that physical activity improves my ability to respond to stressful situations, but as a physiologist, I naturally wonder about the biological basis of this observation.

The hippocampus—one of the brain regions that regulates anxiety levels—becomes activated during both exercise and stress. Research suggests that exercise can calm some of the nerve cells in the hippocampus that become overstimulated during times of stress. While we don’t fully understand the mechanisms, we do know that certain chemical signals in the brain inhibit nerve cell activity, and some of these signals are likely responsible for the observed reduction in stress and anxiety.

Reduced anxiety and stress immediately after physical activity is not the only benefit of exercise. Blood pressure also declines to healthier levels within minutes after exercising. Studies suggest that exercise causes vasodilation, or widening of the blood vessels. When blood vessels open wider, it allows the blood to flow more easily, thereby lowering the pressure of the blood inside the vessels. Activation of histamine receptors is one mechanism that contributes to the reduction in blood pressure following exercise.

While there are many other benefits to regular exercise, the reductions in stress and blood pressure occur immediately and last for many hours. So, consider engaging in a physically active lifestyle that includes daily exercise, and encourage family and friends to join in. The result could be less stress, less anxiety, and lower blood pressure. What better way to start 2018?

william-farquharWilliam B. Farquhar, PhD, is a professor in the department of kinesiology and applied physiology at the University of Delaware. In addition to being a member of the American Physiological Society, he is a Fellow of the American College of Sports Medicine.

 

Taking Ibuprofen during Exercise May Cause More Harm than Good

Man Running Uphill

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Every January gym memberships spike and the wait to get on the treadmill gets longer. This happens because about 40 percent of Americans make New Year’s resolutions, the most common of which are exercising more and improving fitness. Some people may believe in the concept of “no pain no gain,” but it’s a common misconception that if your muscles don’t feel sore then you are not working out hard enough. Many athletes reach for nonsteroidal anti-inflammatory drugs (NSAIDs) to ease the aches and pains of a hard workout. Naproxen and ibuprofen are two commonly used NSAIDs that are available over the counter. Studies estimate that up to 75 percent of long-distance runners take NSAIDs before, after or during training.

Microscopic tears in the muscles cause soreness following strenuous exercise. In response to injury, the body produces compounds called prostaglandins, which play an important role in healing. NSAIDs reduce pain by slowing the production of prostaglandins, which reduces inflammation. The problem is that inflammation also plays an important role in healing damaged muscle as well as helping the muscle growth that occurs with regular exercise. In other words, taking NSAIDs after a workout may not necessarily be a good thing.

A recent study in mice found that levels of a specific prostaglandin increased after minor muscle injury. This particular prostaglandin stimulated regeneration of new muscle stem cells to repair the damage. But when the mice were given NSAIDs their bodies produced fewer active stem cells, leading to weaker muscles even after the injuries had healed.

Other negative effects, such as kidney injury, have been associated with NSAIDs. In one study, elite athletes took either 400 milligrams of ibuprofen or a placebo every four hours during a 50-mile race. At the end of the race, more than 40 percent of the runners tested high for creatinine, a marker of kidney injury. Runners who took ibuprofen instead of the placebo were more likely to develop kidney injury and their degree of injury tended to be worse. The study did not explain why ibuprofen may cause kidney injury in elite athletes, and it’s not clear whether the risks are similar in people participating in less-intense workouts. More studies are needed to examine the effects of ibuprofen following different types of exercise.

If exercising is one of your New Year’s resolutions, start off slow to avoid muscle pain. If you do overdo it, try easing your aches with a warm heating pad before reaching for the ibuprofen.

John ChathamJohn Chatham, DPhil, is a professor of pathology and director of the Division of Molecular and Cellular Pathology at the University of Alabama at Birmingham.

Turkeys and Treadmills: Identifying Gait Transitions in Grounded Running

Fall turkey

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Turkeys are the center of attention at Thanksgiving. But to APS member and Undergraduate Summer Research Fellow Karina Vega, the feathered fowls were the center of a research study that looked at their transition from walking to running. Karina, a biology major at California State University, San Bernardino, studied turkeys while they ran on exercise treadmills in order to study stride frequency and length.

“While running, humans experience an aerial phase, which is when both feet are off the ground at the same time. Turkeys are unique in this aspect in that they instead partake in grounded running, or running without an aerial phase.  Turkeys may not seem like the most ideal animal model, but have been proven to be useful for studies that are interested in running mechanics and energetics to define principles that apply to plenty of other animals.” – Karina Vega

As you might imagine, getting a group of turkeys to cooperate is not easy. Read more about Karina’s work, including what she finds most surprising and challenging about the day-to-day life of a scientist, on the APS Undergraduate Researcher blog.

Erica Roth

Muscle Rebuilding on the Colorado Trail

autumn mountain biking woman

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“That day, for no particular reason, I decided to go for a little run. … For no particular reason I just kept on going. I ran clear to the ocean. And when I got there, I figured, since I’d gone this far, I might as well turn around, just keep on going.” – Forrest Gump

The feats of ultra-endurance athletes are remarkable and sometimes incomprehensible. There are few published data on how the body deals with the stresses of an ultra-endurance event because the fieldwork is difficult to perform without interfering with the athlete’s performance. A new study published in the Journal of Applied Physiology explores how muscle deals with prolonged exercise performed in an “unfriendly” environment (high mileage at high altitude). The primary question these researchers wanted to know: In an event that requires a lot of energy, would the muscles have enough energy to rebuild and adapt to the stress?

The researchers studied a single cyclist during a mountain bike race that spanned 497 miles from Denver to Durango, Colorado, along the high-altitude Colorado Trail. The participant rode 19 to 20 hours each day for five days. The investigators took muscle and blood samples at the beginning and end of the race and compared the changes to a period of normal exercise training.

They found that during the race, the muscles were able to make mitochondria—which are responsible for producing energy in the cells—at an extremely high rate. In addition, the mitochondria increased their ability to use fat energy sources, an important adaptation for long-term exercise. The proteins that contract the muscle also continued to build, but not at a rate fast enough to maintain the muscle’s size, which led to the muscle shrinking in size. In addition, there was significant muscle damage and inflammation. The blood samples also showed evidence of significant stress with changes that were consistent with impaired kidney and liver function.

Overall, this study suggests that when the body is performing an exceptionally, energetically challenging activity, muscle is able to rebuild at an extremely high rate, although maybe not enough, to try to adapt to its new demands. In this case, the extreme stress of the race caused significant muscle damage and organ dysfunction. Scientists hope to continue to find new approaches to study the demands of ultra-endurance athletes to better understand the limits of human performance.

 

Ben MillerBenjamin Miller, PhD, is an associate professor in the department of Health and Exercise Science at Colorado State University. He co-directs the Translational Research in Aging and Chronic Disease (TRACD) Laboratory with Karyn Hamilton, PhD.

Fact or Fiction: Does Coca Candy Prevent Altitude Sickness?

Trekker resting in height mountain

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This summer, I spent a month studying at the Universidad de los Andes in Chile. We visited the Atacama Desert, the driest non-polar desert in the world. It is nestled between two sets of mountains; during one of our excursions we hiked up the Andes Mountains to a village called Socaire, located at an altitude of around 11,000 feet above sea level.

Our site coordinator, physiology professor and “temporary mom,” Anne Crecelius, PhD, kindly offered us coca candy, hoping it might prevent the dizziness, nausea and headaches sometimes associated with altitude sickness. She had asked us to drink more water than we usually do, too, just in case anyone in our group responded badly to being so high up. Coca candy is made in part from coca leaves, a plant that local people have chewed on for thousands of years. Coca leaves contain chemical compounds called alkaloids, which have been shown to reduce hunger and calm the side effects of high-altitude travel.

The question remains whether coca really has physiological benefits. The research is mixed. Some studies, citing the uses of coca throughout history, claim that there are significant benefits to chewing coca leaves. They recount improved energy efficiency during exercise, boosted energy levels—similar to the effect of caffeine in coffee—and decreased thirst and appetite.

However, other researchers suggest that the effects of coca leaves are mostly psychological, similar to a placebo effect (using a fake treatment, or placebo, in a group of people to compare the effects with people using a real treatment). In some cases, the group taking the placebo will also see improvement in their condition.

Even if coca leaves do prevent altitude sickness symptoms, the candies we munched on did not contain enough coca to help much. But perhaps they were enough to create some sort of placebo effect in our group, as no one was sick, just a little out of breath. Nevertheless, we enjoyed the town, the candy and a snowball fight near a very old church. Who knew that a small town at high altitude could be so much fun? Most likely, the locals and generations of indigenous people, who also know of the power of coca.

Andrew KramerAndrew Kramer is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes, studying nutrition, sports and research in the context of the Chilean culture. This is the second in a three-part series that spies physiology in this dynamic South American country. Read part one.

 

Can Exercising in Low-Oxygen Conditions Help Breast Cancer Survivors?

Supporting each other in the race against breast cancer

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Physical activity has been linked to a lower risk of developing several types of cancer, including breast cancer. Walking a few hours a week may even decrease the risk of a breast cancer recurrence as well as dying from the disease. The American Cancer Society currently recommends that people recovering from cancer should exercise at least 150 minutes per week.

But people with breast cancer often face a number of challenges to establishing a regular exercise program. Chemotherapy and radiation can affect heart and lung function, and about 60 percent of breast cancer survivors have reduced strength in their legs as a result of a loss of muscle mass. In addition, more than 80 percent of women gain weight after a diagnosis of breast cancer. These factors, along with fatigue from treatment, can prevent breast cancer survivors from being as active as they want to be.

Knowing that exercise is beneficial for people with breast cancer but that they face challenges, researchers at the University of Alabama at Birmingham (UAB) are looking at new ways to improve breast cancer survivors’ response to exercise. Their study compares the effects of exercising under low-oxygen conditions—similar to that seen at an altitude of 7,000 feet—with exercising in normal oxygen conditions at sea level.

Elite athletes sometimes train in mountainous areas—between 5,000 and 8,000 feet above sea level—to improve their performance. The air at high altitudes is thinner and contains less oxygen. Lower oxygen levels help boost the number of red blood cells that carry oxygen around your body. Exercising at high altitudes also lets you train harder without the added stress on your joints and muscles that occur at sea level.

While it is impractical to take cancer survivors to the mountains, UAB researchers are trying to bring the mountains to the patients During exercise sessions, participants wear a mask that is connected to a machine that controls the amount of oxygen they breathe in. This mimics the low-oxygen levels of a high-altitude workout.

The study is ongoing, so it is too soon to know how beneficial exercising under lower oxygen levels will be. However, the researchers predict that exercising in low-oxygen conditions will trigger a number of physiological changes that will let people with breast cancer be more active and improve their overall health. If the results of the study are correct, it may lead to new approaches to help breast cancer survivors lead a more active life.

 
John Chatham

John Chatham, DPhil, is a professor of pathology and director of the Division of Molecular and Cellular Pathology at the University of Alabama at Birmingham.

Not Horsing Around: Therapeutic Effects of Horseback Riding

Anne with students and Paralympians

Anne R. Crecelius, PhD, and students visit with La Roja Paralimpica athletes in Chile.

Choosing your favorite part of a trip can be a difficult decision for travelers. I had countless unforgettable and unique experiences during a recent four-week trip to Chile. One excursion that stands above the rest was a weekend trip to San Pedro de Atacama in Northern Chile.

I was studying with a group of students who had booked a horseback riding tour through the oasis of Sequitor. With the Andes Mountains as our backdrop, we spent two hours enjoying the perfect blue sky, warm sun and crisp air. This small agricultural region is in what is often called the driest desert in the world.

I had never been horseback riding and did not realize how much coordination, strength

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Molly Gearin tries her hand at horseback riding.

and physical and mental stamina it required. I later learned that horseback riding is a type of rehabilitative treatment—called hippotherapy—that may improve coordination, balance and strength in people with physical disabilities, including cerebral palsy (CP).

CP is a neurological disorder that affects body movement and coordination. Studies have shown that hippotherapy can improve joint stability, balance and painful muscle contractions in people with CP. Children with CP may especially benefit from hippotherapy. Therapeutic riding can change how the abdominal and lower back (core) muscles respond to different movements. These physiological benefits can improve posture and the overall quality of life in some children, particularly among those who have the ability to walk, run and jump.

Researching hippotherapy was not the first time I thought about people with CP on our trip to Chile. Another favorite activity was our opportunity to watch La Roja Paralimpica, the Chilean Paralympic Fútbol 7-a-side team, practice. This sport is adapted from traditional fútbol (soccer) to accommodate athletes with disabilities. The modified rules allow Paralympic athletes to enjoy a sport that is at the heart of Chilean culture.

As a future physical therapist, I enjoyed observing elite athletes at work and learning about hippotherapy, an activity that could be of benefit to people with CP.

– Molly Gearin (Anne Crecelius contributed to this post)

Molly Gearin is a pre-physical therapy major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes studying nutrition, sports and research in the context of the Chilean culture. This is the first in a three-part series that spies physiology in this dynamic South American country.

 

 

Like Father, Like Son (and Daughter): How Your Dad’s Past Affects Your Future

Happy daughter playing with dad

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What makes your father the best dad in the world? Maybe it’s his sense of humor or the times he has taken you to the movies or played catch in the yard. Or maybe it’s the fact that he made healthy lifestyle choices before you were born. Recent research suggests that your father’s health before you were conceived (preconception) may change the way your genes behave to affect your future health. It almost sounds like something out of a science fiction movie, but it’s real.

Studies tend to focus on the mother’s preconception health and the risks her baby might face later in life if she’s overweight. But a dad’s weight and early eating habits can also play a role, according to research published in the American Journal of Stem Cells. Researchers found that offspring of men who were obese before reproducing were more likely to have diabetes and be overweight. On the other hand, the researchers also found that fathers who had limited food resources in their early life caused genetic changes that protected their children—and even grandchildren—against cardiovascular disease.

Most people know that exercise is one of the healthiest lifestyle choices you can make to maintain your weight and keep your heart and even your brain healthy. However, research presented at the APS Integrative Biology of Exercise 7 meeting showed that offspring of men who exercised long term before conceiving had a higher likelihood of being obese and developing diabetes. This result was a huge surprise to the research team, but is it a reason to stop exercising? Not really. The study focused on how efficiently the body used energy on a high-fat diet. Limiting dietary fat and being active is still the way to go for most people.

Keeping stress levels low is also a good plan for dads-to-be. One study suggests that a man’s preconception stress may program his kids for mood disorders. Researchers found a pathway in the brain that transmits signals about stress hormones, and it may be passed down to the next generation.  If the signal is passed on to you, then your father’s stress levels could affect your predisposition for anxiety and depression.

These studies represent clues to learning how genetic material is transformed as it passes through generations. It’s also a reminder that following a healthy diet, staying active and maintaining mental health is important for everyone at every age.

Happy Father’s Day!

– Erica Roth

Is Running Barefoot Better than Wearing Shoes?

woman's feet running on gravel road

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Visit any sporting goods store today, and you’ll see a wall display full of running shoes for all types of runner, from sprinters to marathoners and everything in between. Before the 1970s, however, specialized running shoes weren’t readily available, and most runners ran with minimally supportive shoes or without any shoes at all.

It is easy to imagine how people could run shoeless along unpaved roads a hundred years ago, but on U.S. streets today? That’s a bit harder to picture. Still, barefoot running has grown in popularity over the past two decades. The question remains why a runner would want to strike hard ground with the tender sole of his or her foot instead of a cushioned running shoe. The answer may be that barefoot runners have fewer impact-related injuries.

Researchers set out to determine if there was a difference in the way barefoot runners’ feet strike the ground and if this decreased the force the runners felt in their joints. The research team studied three groups: U.S. runners who always ran in shoes, Kenyan runners who grew up running barefoot but now run in shoes and U.S. runners who started their running careers wearing shoes but now run barefoot. They found that athletes who have always worn shoes tended to land heel first and then roll up onto their toes, unlike barefoot runners who tended to land toe first. The Kenyan runners—who came late to the practice of running with shoes—also landed toe first, suggesting that early barefoot running can influence foot landing even when the runner starts wearing shoes.

Running is a high-impact activity that generates large forces when the feet strike the ground. This impact often causes injuries, particularly in high-mileage athletes, who are prone to repetitive motion injuries. When the researchers examined the force of foot-strikes, barefoot runners struck the ground with much lower forces than those wearing shoes. The lower strike force seems to be directly linked to landing toe first instead of heel first. Barefoot runners also lower their center of gravity more than runners who wear shoes. This decreases the stress on their legs during a foot strike and allows for more “give” in their stride. The lower impact of barefoot running is interesting because running shoes are designed to cushion the foot and protect against forceful impact.

Barefoot running seems to be easier on the body and results in fewer injuries. National Go Barefoot Day is June 1, and Global Running Day is June 7, so get out there and try a short barefoot run!

 

Jessica Taylor 2017

Jessica C. Taylor, PhD, is a physiologist, medical educator and exercise enthusiast.  She was previously the executive director of the Mississippi Osteopathic Medical Association and will be joining the APS staff as the Senior Manager of Higher Education Programs this summer.