Scientific Research

What Animals Can Teach Humans about Muscle Maintenance

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Hiding Groundhog

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We all know the saying “use it or lose it.” Your muscles and nerves are no exception. When people are not active, whether it’s because of bed rest, spinal cord and nerve injury, or other reasons, two big problems arise. First, the muscles shrink by losing protein (a state called atrophy). Second, nerve cells have trouble firing electrical signals to communicate with the muscles. This combination can make it harder for people who are inactive to perform normal activities in their daily lives.

Unlike in humans, inactivity in other animals is not always such a bad thing. Certain animals in the wild need to stay inactive (dormant) to survive in their environment. During times of low food availability and harsh environmental conditions, ground squirrels, frogs, bats, turtles and bears may remain inactive. In the winter, this is called hibernation, and in the summer, it’s known as estivation. Quite often, these animals’ muscles are less active than normal or completely inactive for several months at a time. Some frogs can even survive under water during the winter without using their breathing muscles. Based on the idea of  “use it or lose it,” you might think that hibernating animals wouldn’t be able to run, jump, fly or even breathe normally after months of not using their muscles. Think again!

Understanding how animals immediately return to using their muscles and nerves normally after long stretches of dormancy is a major area of research. By learning how different animals dodge neuromuscular problems related to inactivity, scientists can figure out why human muscles and nerves are not as well-equipped. For example, hibernating animals activate genes that reduce the loss of muscle protein and use less energy during periods of inactivity to avoid atrophy. These discoveries have the potential to provide new treatment options for people who are confined to bed rest or who suffer nerve injuries that leave muscles unable to contract.

Animals have already solved many problems that plague humans, such as nerve and muscle inactivity. Research that compares animal and human function is an example of comparative physiology. Comparative physiology findings can help scientists make important discoveries that would not be possible if the cures hiding inside animals were overlooked.

Joe SantinJoe Santin, PhD, is a postdoctoral fellow at the University of Missouri-Columbia.

 

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

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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.

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

Putting Out Fires Hurts Firefighters’ Hearts

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As the temperature outside rises, our bodies make adjustments to keep our internal temperature constant to prevent us from overheating through a process called thermoregulation. This includes bodily functions such as sweating and widening of the blood vessels (vasodilation). When we sweat, perspiration evaporates from our skin to cool us down. When the blood vessels under our skin widen, our heart pumps more blood to our skin, which releases more heat from our inner body.

Our bodies are constantly working to hold a steady core temperature around 98-100 degrees Fahrenheit (F). This allows our organs to function properly. But when the temperature outside is extremely hot, our temperature can start to rise. A person with a body temperature above 104 degrees can develop heat stroke. This can cause dizziness, difficulty breathing, confusion, seizures or loss of consciousness. Brain and heart damage—sometimes permanent—can occur when body temperature climbs above 107 degrees F.

Too much summer heat can be unhealthy for everyone, but it can be especially dangerous to firefighters. The incidence of fires increases in the U. S. during the summer months. Firefighters fight almost twice as many fires in the summer compared to the rest of the year. On top of dealing with the extreme heat (sometimes over 700 degrees F!), these first responders face extreme physical exertion, mental stress and smoke inhalation on the job. All of these factors together can place firefighters in immediate danger of heat exhaustion, heatstroke and heart problems. In fact, firefighters are up to 136 times more likely to die from coronary artery or heart disease during or soon after they suppress a fire.

In a study published in Circulation last month, researchers may have uncovered several reasons why putting out fires puts firefighters at risk for heart disease. They discovered that a single, 20-minute session of fire simulation training—where healthy firefighters were exposed to physical activity in the extreme heat (about 755 degrees F)—was enough to injure their blood vessels, even though the firefighters’ core body temperature never reached above 101 degrees F. The problem: Although the firefighters’ bodies did keep their core temperature within a healthy range, their blood vessels did not relax properly immediately after the training. Also, as a result of the training, the firefighters’ blood clotted more easily. Damaged blood vessels and increased clotting of the blood can be very harmful to the heart and sometimes can lead to a heart attack.

This research shows us that even when we are able to keep our body temperature from getting too high, there are hidden dangers of being physically active in extremely hot temperatures. So keep your heart healthy this summer and don’t overexert yourself while outdoors!

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.

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!

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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:

Close up shot of runner's shoes

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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.

Dressage test

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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

What Alcohol Can Do to Your Body Is Not Always So “Cheer”y

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“Cheers!” is a word often associated with alcohol consumption, conjuring up images of celebration and good times. However, it is important to remember that alcohol is a drug as much as any other drug, prescription or otherwise. In fact, alcohol is the most widely abused drug in the U.S. Alcohol misuse affects every organ in the body and has both long- and short-term consequences.

Drinking too much alcohol on a regular basis most significantly affects the liver, a major organ responsible for processing many substances in our bodies. The liver eliminates alcohol from the body through a series of steps using substances called enzymes. Enzymes break down alcohol into other materials called metabolites that the body can more easily handle (or get rid of). Some metabolites produced in the breakdown of alcohol are toxic. Excessive, long-term exposure to these toxic chemicals can lead to inflammation, liver tissue damage and even cancer.

Long-term effects of alcohol can cause several types of liver disease, including:

  • Alcoholic fatty liver disease. It’s one of the earliest stages of liver disease. Too much alcohol can cause fat deposits to form in the liver. Abstaining from alcohol can reverse the damage from alcoholic fatty liver disease.
  • Alcoholic hepatitis. In addition to fatty deposits, this disorder also causes scarring of the liver and impairs liver function. Mild cases may be reversible, but severe cases can lead to liver failure.
  • Alcoholic cirrhosis. The most serious of alcohol-related liver injuries, alcoholic cirrhosis leads to hard scar tissue that replaces healthy liver tissue, causing extreme damage to the organ. Severe liver impairment can lead to significant problems with overall health and nutrition, gastrointestinal bleeding and even death. Abstinence can’t reverse cirrhosis, but staying away from alcohol may prevent further damage and improve symptoms. Cirrhosis symptoms may also be managed with medications and medical treatment. However, some patients may need a liver transplant to improve their health.

Alcohol affects brain function, too. A recent study showed that even short-term exposure to alcohol decreases the brain’s ability to get enough glucose, an important nutrient. Abstinence from alcohol can help the brain recover, but healing isn’t immediate.

It’s not all bad news, though! Research suggests that moderate consumption—defined as one drink per day for women and two per day for men—especially of red wine, can benefit cardiovascular health in adults. However, moderation is key, and any drinking in people younger than 21 is considered detrimental to health and development.

April is Alcohol Awareness Month. If you suspect that you or someone you know has a drinking problem, the National Drug and Alcohol Treatment Referral Routing Service can provide information and resources (800-662-HELP).

–Audrey Vasauskas

When’s the Best Time to Eat? Your Body Clock Knows

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The American Heart Association recently released a statement suggesting that when and how often you eat could affect your risk for developing heart disease and stroke. Until now, the focus on diet has been primarily about how much and what you eat. This news—that the time of day you eat may also be important—could change the way people are able to manage their health.

Our bodies have natural daily patterns called circadian rhythms that occur roughly over a 24-hour cycle. Many biological processes are driven by circadian rhythms, including when you go to sleep and wake up, your body temperature, heart rate, blood pressure and the release of various hormones. A “master clock,” a tiny group of cells called the suprachiasmatic nucleus (SCN), located in the hypothalamus area of the brain manages circadian rhythms. This master clock is mostly controlled by changes in light.

Every cell in the body also has its own internal clock called a “peripheral clock.” Peripheral clocks make sure all of the cells’ functions are coordinated with the master clock. Animal studies show us the importance of keeping peripheral clocks in sync with the brain’s master clock. For example, when the peripheral clock in a mouse’s heart is disrupted, the mouse develops heart failure and dies at a much younger age than normal mice.

Unlike the master clock, peripheral clocks are more responsive to the availability of food than changes in light. As a result, eating at the “wrong” time of day could shift the rhythms of the peripheral clocks so they are out of sync with the master clock. For example, shift workers who work in the middle of the night are active when they would normally be asleep and eat at times when their body doesn’t expect food. They are at much greater risk for being overweight, becoming insulin resistant and developing cardiovascular disease because their master and peripheral clocks are likely to be out of sync.

Research in mice has shown that if they consume a high-fat meal at the end of their active period (the equivalent of a high-fat dinner for humans) they gain more weight, develop insulin resistance and have impaired cardiac function compared to mice that eat the same high-fat meal at the beginning of their active phase (breakfast).

Studies in people suggest that eating meals late in the day is linked to negative health effects, but a direct relationship has not been shown. Nevertheless, if when you eat is just as important as what you eat, it might not hurt to eat your larger meals earlier in the day if you can.

 

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.

Meet Christina McManus, Associate Professor of Physiology

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Christina McManus

Christina McManus, PhD, teaches physiology at the Alabama College of Osteopathic Medicine.

March is Women’s History Month, a time when women who have challenged—and continue to challenge—traditional roles are celebrated. In the final installment of our series, we introduce you to APS member Christina McManus, PhD, an associate professor of physiology at the Alabama College of Osteopathic Medicine. (Read part one, part two, part three and part four).

What is your title/role?

I am an associate professor of physiology at the Alabama College of Osteopathic Medicine (ACOM).

What is your area of research?

My clinical research includes studying the changes in biomarkers (indicators of the presence of disease) in patients with chronic back pain who receive osteopathic manipulative therapy.

My medical educational research includes hosting a “Women in Science” camp designed to encourage and educate middle and high school girls about science-related careers.  We evaluate the girls’ interest in science careers before and after they attend.

How did you become interested in science? Were there women scientists who influenced you or whom you admired?

I always had an interest in science in middle and high school.  I grew up in a small town and didn’t know any women in science-related careers other than nurses.  When I went to college at the University of South Alabama, I took an honors research class and met some fascinating women researchers.  Being around a group of successful, confident and intelligent women—of diverse ages and backgrounds—made a huge impact on me.

What do you like most about your job?

I like teaching physiology and making a hard concept easy and medically relevant to medical school students. I have a great passion for our outreach programs at ACOM, such as the “Women in Science” camp.  More than 125 girls participate [in the camp]. It brings me much joy to provide them with the experience and exposure that I lacked as a kid.

What are your biggest challenges?

My biggest challenge is always finding a new and exciting way to teach science to kids of all ages and backgrounds.

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What do you see as the main barriers to having more women in STEM?

The biggest barrier in my opinion is that young women may not know anyone in a STEM field, and most of these jobs are held by men. Therefore, they don’t see how a woman can be successful in the sciences.

What would you say to young girls with an interest in science/physiology? How would you encourage them to pursue their studies?

I would encourage them to never limit themselves, and be anyone they want to be.  [They should] reach out to as many women as they can in this field [as mentors].  They will be amazed at the possibilities for women in STEM if they search hard enough.

– Erica Roth

Ida Henrietta Hyde: A Trailblazer in Physiology

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hyde1

Ida Hyde at Heidelberg University, 1896.

March is Women’s History Month, a time when women who have challenged—and continue to challenge—traditional roles are celebrated. This month, the I Spy Physiology blog will introduce you to several female physiologists, starting with the first female member of APS, Ida Henrietta Hyde.

Ida Henrietta Hyde was born in 1857 in Davenport, Iowa, the daughter of German immigrants. She went to public school and took jobs as a dressmaker and milliner (a person who designs or sells women’s hats) to help support her family. After reading a book about natural science, she became fascinated with biology. This newfound interest in life sciences inspired her to save as much of her salary as possible so that she could go to college someday.

In 1882, Hyde started classes at the University of Illinois at Champaign but was soon forced to withdraw to help care for her sickly brother. During that time, she taught elementary school in Chicago, where she was instrumental in introducing a science curriculum to the Chicago public school system.

By the late 1880s, Hyde was able to return to college and went on to earn a degree in biological sciences from Cornell University in Ithaca, N.Y. She worked in research at the Marine Biological Laboratory at Woods Hole in Massachusetts before traveling to Europe on a fellowship to pursue a PhD—something women were rarely able to do. Hyde’s early work centered on the neurophysiology of vertebrates and invertebrates, but she also conducted research in cardiology. Her article “The Effect of Distention of the Ventricle on the Flow of Blood through the Walls of the Heart” was published in the first issue of the American Journal of Physiology in 1898.

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By 1902, Hyde was back in the U.S. and had become an associate professor of physiology at the University of Kansas. She eventually became head of the department and was nominated for APS membership in 1902. She was the only female member of APS until 1913. Today, APS is proud to count more than 3,100 women as members.

APS membership was just one of Hyde’s many accomplishments as a scientist and physiologist. Her landmark achievements paved the way for many more women who follow in her footsteps. Read more about her in The Physiologist.

– Erica Roth