Muscle Rebuilding on the Colorado Trail

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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

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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?

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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.

Walking and the Brain, Aromatherapy for Horses and a Whole Lot More!

Physiology, the study of function from microscopic cells to complete organ systems, encompasses a wide range of fascinating topics. The annual Experimental Biology (EB) meeting is a showcase for thousands of researchers studying humans and animals alike. Check out some of the research presented at last month’s meeting in Chicago:

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Most people know that walking is good for heart health, weight management and flexibility. New research from New Mexico Highlands University reveals how your brain also benefits from walking. Each step you take sends pressure waves through your arteries and increases blood flow—and oxygen—to the brain. The researchers found that running also had a beneficial effect on blood flow, while sports like cycling that don’t involve foot impact were less likely to make a significant difference.

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Do you like the calming scent of lavender when the pressure’s turned up? Turns out, you’re not alone. Research out of Albion College studied the effects of aromatherapy on horses. Much like people, competition horses get stressed out when they’re transported from their home to an unfamiliar venue. Stress reduction therapies are highly regulated in competition horses, and non-medicinal treatments could go a long way to calm the animals before they perform. The researcher found that stress hormone levels dropped significantly among trailered horses that were exposed to lavender aromatherapy when compared to distilled water mist.

Two women rowing on a lake

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Olympic-caliber athletes appear to be the picture of strength and power. But new research suggests that high-intensity workouts without a proper recovery period could interfere with optimum bone health. A study of female Olympic rowers from Canada’s Brock University showed that the levels of a protein that stops bone mineral loss dropped during extended periods of heavy training. Bone mineral loss weakens the bones and increases the risk of stress fractures and osteoporosis.

These studies just scratched the surface of all the top-notch physiology research presented at EB. Read more highlights from this year’s meeting:

Why vitamin A and a high-fat diet don’t mix

The role of immune cells in the cause—and treatment of—preeclampsia

How an ice bag on the face can help treat severe blood loss

An “exercise pill” may be in our future

How orange essential oil reduces PTSD symptoms

 

Erica Roth

How Obesity Fuels Inactivity

 

Women jogging in Central Park New York

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More than one in three adults and one in six children in the U.S. are obese. Obesity—defined as a serious degree of overweight—is a leading cause of death, disease and disability. Although obesity has been linked to genetic disorders, it is most often caused by unhealthy behaviors and, therefore, is preventable and reversible.

Throughout the day, we get calories from food and we burn the calories off when we move our bodies. When we eat more calories than we burn, our bodies store the excess calories as fat, which accumulates over time. Eating too many calories and not moving enough are two factors that can cause obesity. Only one in five adults in the U.S. meets minimum physical activity recommendations, making physical inactivity a significant contributor to obesity. People who are overweight need to eat fewer calories and/or increase physical activity to lose excess fat. These lifestyle changes are often challenging, and may be compounded by the fact that exercise may be harder to do when you’re obese.

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 The cycle of obesity. Credit: Kim Henige

Carrying excess body weight can make joint pain more likely, which makes physical activity more difficult. Now, researchers may have discovered another reason excess body weight makes physical activity more difficult. A recent study published in the Journal of Applied Physiology shows that the working muscles of obese mice tired out more quickly than those of lean mice. These findings support a cycle of obesity where inactivity leads to obesity, which leads to more inactivity. Breaking the negative cycle of obesity and re-establishing a healthy body weight is possible, but takes considerable dedication and persistence to overcome the barriers and discomfort of the process.

Remember that the path to a healthier weight starts by taking a step! Visit the Centers for Disease Control and Prevention website for weight loss strategies, success stories of people who’ve lost weight and kept it off and more.

Kim HenigeKim Henige, EdD, CSCS, ACSM EP-C, is an associate professor and undergraduate program coordinator in the department of kinesiology at California State University, Northridge.

Microvesicles and Blood Vessels and Exercise, Oh My!

Swimming

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The American Heart Association recommends that adults get at least 30 minutes of endurance exercise every day to keep your heart, lungs, and circulatory system healthy. A daily workout can help reduce your risk of developing diseases such as diabetes, heart disease and stroke. Endurance exercise is basically any activity that increases your breathing and heart rate for an extended period of time. Examples include:

  • brisk walking
  • jogging
  • dancing
  • biking
  • swimming
  • climbing stairs

During exercise, your blood vessels expand (dilate), increasing blood flow, and delivering more oxygen to your working muscles. Over time, exercise helps your blood vessels become more flexible. This flexibility allows the vessels to dilate more quickly to deliver blood and oxygen to your muscles. Long-term endurance exercise also increases the number of small blood vessels (capillaries) in your body. All of these things help carry more oxygen to your organs and remove waste more quickly. As a result, you can enjoy better athletic performance, such as being able to jog farther, run faster or swim longer distances.

A recent study in the American Journal of Physiology—Heart and Circulatory Physiology showed that endurance activity may help blood vessels grow by increasing the number of microvesicles in your blood. Microvesicles are small particles that are shed into your blood from all types of cells in your body. When volunteers in the study rode a stationary bicycle, they produced more microvesicles than when they were sitting and resting. The number increased even more when they pedaled faster. The researchers then added the volunteers’ microvesicles to endothelial cells—a type of cell that lines the blood vessels and is responsible for expanding and contracting them. They found that microvesicles caused endothelial cells to grow twice as fast. In other words, when you exercise, the number of microvesicles increases, which in turn helps your blood vessels grow.

Now you know why exercise builds a better circulatory system, so get moving!

Dao Ho, PhD

Dao H. Ho, PhD, is a biomedical research physiologist at Tripler Army Medical Center. The views expressed in this blog post are those of the author and do not reflect the official policy or position of the U.S. Department of the Army, U.S. Department of Defense or the U.S. government.

Are Cross-Country Skiers Premier Athletes?

 

Cross Country Skiing Couple

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With winter upon us, it is a good reminder that cold weather is not an excuse for inactivity. Athletes from cold-weather climates, such as the Nordic countries, are not content to stay indoors during winter. In fact, cross-country skiers from these colder climates might be considered the premier human aerobic athletes.

Although some picture cross-country skiing as slowly shuffling along at a leisurely pace, the reality of competition is much different. For example, the winner of the 50 km (31 miles) freestyle at the 2014 Winter Olympics finished the race in less than one hour and 47 minutes. That’s longer than a marathon but finished in less time. And these races typically go uphill for 50 percent of the time!

Physiologically, skiing is interesting from many perspectives. The biomechanics of skiing are interesting because the arm and leg movements must be coordinated to efficiently move forward. The whole-body nature of skiing makes the physiology fascinating to study. Cross-country skiing puts large demands on the heart to deliver blood and oxygen to exercising muscle. This challenge is greater than for running or cycling (which engages only the legs) because both the arms and the legs need to work with skiing.

The amount of blood going to the arms versus the legs constantly changes, too. These changes are based on the hundreds of technique transitions needed to cross the varying terrain during a race. The great physical endurance required improves the ability of cross-country skiers’ muscles to use oxygen. These athletes have some of the highest levels of oxygen consumption (VO2max) on record. Legendary physiologist Bengt Saltin and other researchers have used the unique whole-body nature of cross-country skiing to study blood flow delivery. This approach has provided us great insight into the regulation of blood flow in both athletes and non-athletes.

Cross-country skiers demonstrate that cold weather is not an excuse to be sedentary, but rather an excuse to be great.

 

Ben Miller Benjamin 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.