What Animals Can Teach Humans about Muscle Maintenance

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.

 

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.

 

 

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:

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

Bring on Winter! (But Stay Safe and Healthy)

 

girl playing on a winter walk

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Winter officially begins next week with the winter solstice—the day of the year with the fewest hours of sunlight—on Dec. 21. With the cold weather and shorter days, you might be tempted to curl up under a blanket until the spring thaw. Whether you plan to hibernate or get outside to enjoy the chill, we’ve got some good reads about how our physiology responds to the cold weather.

Check out these throwback posts featuring cold weather tips to help you stay safe and healthy during the coldest months:

Have fun, be safe and take note of how your body adapts to the season!

Stacy Brooks and Erica Roth

 

 

If Only Birds Could Compete in the Summer Games

Frigatebird - Max Planck Ins

Frigatebird. Credit: Max Planck Institute.

Endurance is a hard-won characteristic of many elite athletes and is vital to winning most sporting competitions. If great frigatebirds could compete this summer, they would certainly take home a medal for endurance flight.

Frigatebirds are large sea birds with wingspans of more than six feet across. They are really good at gliding and can fly nonstop for weeks at a time. Researchers who study these birds suspected the birds got some shut-eye during these flights.

Recently,  Max Planck Institute for Ornithology researchers examined whether these birds are able to take naps while flying—yes, you read that right, while flying. To examine this, the team attached flight data recorders and measured brain activity of birds in flight.

The birds were awake and actively foraging during the day. However, at night the brain activity of the birds switched to a pattern that suggested they were taking short naps that were up to several minutes long while continuing to soar through the skies. In addition, they discovered that each hemisphere of their brain could take turns sleeping (i.e., unihemispheric sleep) or both sleep at the same time (i.e., bihemispheric sleep). Unihemispheric sleep allows the birds to stay partially alert to potential dangers,  watch where they are going and, of course, prevent themselves from falling from the sky.

This made me wonder how they prevent a crash landing when both sides of their brains take a nap. As it turns out, sleep duration for this deeper form of REM sleep only lasted a mere seconds and did not affect their flight pattern. Remarkably, these birds only average 42 minutes of sleep per day while out at sea. Researchers are still trying to figure out how they are able to function on such little sleep when they are known to sleep for more than 12 hours on land.

My thought is there must be a Starbucks in the sky.

Karen SweazeaKaren Sweazea, PhD, is an associate professor in the School of Nutrition & Health Promotion and the School of Life Sciences at Arizona State University.

The Anti-Aging Cure May Be in Your Medicine Cabinet

Older dog - Younger dog

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Rapamycin, a drug used to prevent organ transplant rejection, may also turn back time—in dogs at least. A study is underway to see if rapamycin can delay aging in dogs, and the puppy-like energy of one canine participant, eight-year-old Bela, gives some hope that the drug might work. Rapamycin is one of several drugs prescribed to treat other conditions that are being studied for their potential to help humans grow old without the health problems of aging. These drugs are particularly promising because they are already being used by people and are well-tolerated by the body. Other drugs being investigated include:

  • Metformin: Metformin is a commonly prescribed treatment for type 2 diabetes. The specifics of how it counteracts aging are still being debated, but the scientific community generally agrees that small doses of metformin can improve metabolic health, reduce cancer risk and lengthen lifespan. The Targeting/Taming Aging with Metformin study is currently underway to test if metformin has anti-aging effects in people, as it did in mice.
  • Aspirin: Constant low-level inflammation is considered a hallmark sign of aging, so researchers wonder if anti-inflammatory drugs such as aspirin can help. Studies have found that lifelong use of aspirin lengthens the average lifespan of male mice but does not increase maximum lifespan. No effects have been seen in female mice. Other studies in mice have shown that aspirin can improve immune, metabolic and cardiovascular health. However, aspirin also prevents blood from clotting and irritates the intestines, which can increase the risk of internal bleeding.

Researchers are also looking at lifestyle choices for their fountain-of-youth benefits, including:

  • Vegan diet: A vegan diet reduces the consumption of methionine, a nutrient abundant in eggs and meat. Eating less methionine has been shown to increase the lifespan of yeast, worms, flies and rodents. However, methionine is an essential nutrient for the body, so its anti-aging properties may be counteracted by the health effects of not having enough of it.
  • Calorie restriction: Reduced-calorie diets are a well-established method for extending the lifespan in various species, including certain strains of mice. However, in other mice strains, calorie restriction dramatically shortens the lifespan.

This detrimental effect in mice demonstrates a primary concern for testing anti-aging treatments in humans: A drug or lifestyle switch might shorten a healthy participant’s life. While it will take many years to find out if a treatment can truly increase longevity, we already know that wisdom only comes with time—and age.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.

Of Ice Swims and Mountain Marathons (and So Much More)

If you regularly read this blog, you may know that the research questions that physiologists ask relate to wide range of topics—cells, tissues and organs, insects and animals, and how the environment influences all of these things. Nowhere is this more apparent than at the annual Experimental Biology meeting. This year, thousands of physiology-based research abstracts were presented over five days. Read on to learn about two research studies on extreme sports that caught our eye.

Glacier Dive

Credit: Ram Barkai

Ice swimming is growing in popularity, with hundreds of athletes worldwide giving this chilly sport a try. Human performance in water this cold—swims must take place in water that’s 5 degrees Celsius or colder—has not been well-studied. In a study presented at the EB meeting, researchers looked at how age, gender and environmental factors such as wind chill affected athletes during one-mile ice swims. Among other results, they found that age doesn’t have a large effect on swim times, suggesting that athletes can be competitive in the sport well into their 30s and 40s. This is significantly older than the average age of the athletes on the most recent U.S. Winter Olympic team (26 years old), giving hope to older athletes as the sport is being considered as a new Winter Olympics event.

Man Running Uphill

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Fifty kilometer (~31 mile) mountain ultramarathons test athletes aerobic and anaerobic fitness through changes in elevation, terrain and weather. Aerobic fitness refers to how the body uses energy when there is enough oxygen, such as the energy burn that occurs when running at a comfortable pace. Anaerobic fitness refers to the body’s ability to exercise when there’s not enough oxygen, such as during a sprint to the finish line at the end of a race. While it may seem that aerobic fitness would be a better predictor of how fast a person would finish an ultramarathon, researchers found that competitors with the best anaerobic fitness finished faster. That’s why exercises that build anaerobic endurance, such as uphill sprints, would be a worthwhile addition to the training regimen of anyone preparing for this type of race.

These studies were just the tip of the iceberg. Read more physiology research highlights from the EB meeting:

How exercise to protect the blood vessels from stress

Why a high-salt and high-sugar diet is a fast track to high blood pressure

The benefits of gastric bypass surgery that occur before the weight comes off

Elephant seals that protect themselves with CO2

What tobacco hornworms can tell us about fat metabolism

How an inhaler could protect against life-threatening accumulation of fluid in the lungs

Stacy Brooks

Running a Thousand Miles Can Be Exhausting. How Do Iditarod Sled Dogs Do It?

View of sled dog race on snow

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Have you ever had a morning where you just did not have the energy to go out for your five-mile run? What if you woke up in New York City and had to run to Miami? That is the distance Alaskan Huskies run every year at the annual Iditarod sled dog race. How these amazing canine athletes accomplish this feat is interesting to scientists because it provides insight into how human performance can be maintained in challenging conditions.

Muscles get energy to exercise from glucose (sugar) and fats stored in the body. Muscles use oxygen from the air to transform the two into energy. Scientists originally assumed that the Alaskan Huskies used fat to sustain long periods of exercise. Huskies are fed a diet rich in fat, and the body stores fat in greater quantities than glucose. However, a recent study found that the dogs actually used glucose to sustain exercise and that the glucose was made from a part of fat called glycerol. The dogs took advantage of their fat stores, but they used the fat stores to make glucose.

Why go through the trouble of turning a part of fat into glucose rather than using fat as is?  That answer is not entirely clear yet, but one possibility is that the dogs typically run the Iditarod at an average of 10 miles per hour, or six-minute miles, while pulling a sled. Muscles prefer glucose to fuel intense exercise because they can get more energy out of it for every molecule of oxygen breathed in. Sustaining such high speeds while pulling a load may require the use of glucose over fat. This is not to say that fat is not important for the dogs. As mentioned, the dogs use the fat, just not directly, and fat is good fuel during rest periods and recovery between running.

The Alaskan Huskies were bred to perform these amazing endurance feats, but we don’t know yet if human muscles can invoke the same rate of fat-to-glucose conversion processes to fuel exercise of such long distance. However, humans performing at such high speeds for prolonged periods would most likely need to do this same type of conversion.

Next time you’re not up for your morning run, channel your inner sled dog: Five miles really isn’t that bad.

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.

Ben Miller with sled dog

Dr. Miller with study participant.

Football Safety Tips from Birds? How Woodpeckers Avoid Concussions after Head Impact

Football

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The NFL has been under a lot of heat over concussion injuries in its players and the long-term brain injury and health impacts. With the size of the player and the speed he runs, it’s not hard to imagine the sheer force and damage that can occur from even a single collision. Woodpeckers, though, bang their head about 12,000 times a day at 10 times the impact of the average football hit. Why don’t woodpeckers get concussions?

The human brain floats in the skull in what is known as cerebrospinal fluid. This fluid acts as a cushion between the brain and the skull and helps lessen the impact of a blow to the head. Sudden, violent motions, such has from helmet-to-helmet contact, twist the brain or slam it against the skull. The movement stretches and damages the brain cells, causing problems in how the brain processes information.

Woodpeckers avoid brain injury because of the way their heads are designed. The bird’s brain fits snugly in the skull, so the brain doesn’t slosh around after a head impact. The brain is also oriented differently. Brains are shaped like a walnut: an oval-shaped dome. In humans, the dome faces the top of the head. In woodpeckers, the dome faces forward so the force of an impact is spread over a larger area. Size helps, too. Similar to how a cellphone stays intact after falling off the table while a laptop may not, a smaller brain has a better chance of getting away unharmed after a head injury.

The NFL recently found that more concussions were diagnosed in the 2015 season than in 2014. Officials and team physicians are not sure if the increase is due to more self-reporting by players and active identification of injury by trainers. Let’s root for Super Bowl 50 this Sunday to be full of drama on the field and 100 percent concussion free.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.

Too Cold Outside? Try Out Polar Mammals’ Methods of Staying Warm

If temperatures in the teens (or the 50s for the warmer climates) make you grumble, be glad you’re not a mammal living in the Arctic or around Antarctica. These animals face much colder air temperatures of -40 to -76 degrees Fahrenheit. While humans bundle up with thick sweaters and jackets to get through the winter cold, mammals such as seals, penguins and polar bears stay warm with blubber, feathers and fur. How do these materials keep the arctic chill out?

Polar Bear

Credit: Getty Images

The ability of a material to insulate depends on how easily it lets heat pass through—a property called thermal conductivity. Fat has a low conductivity, which means it slows heat getting out and helps keep heat in. Marine mammals such as whales and seals have a layer of blubber beneath their skin. The blubber insulates their body so they don’t lose body heat while swimming in icy waters.

Feather and fur also have low thermal conductivity and are good for keeping warm. They also trap air—another substance with low thermal conductivity—creating an insulating layer of air around the body. If the animal feels cold, goose bumps fluff up their feathers or fur, which traps more air to slow down heat loss. This is why down jackets are so cozy: Down traps air, and this air layer insulates us.

You can test these materials out for yourself: This experiment in Advances in Physiological Education uses bubble wrap and vegetable shortening to demonstrate how fat and air work as insulators. Show us how your experiment turned out. Tweet a photo and use the hashtag #ISpyPhysiology.

Maggie KuoMaggie Kuo, PhD, is the former Communications and Social Media Coordinator for APS. Catch more of her writing in the Careers Section of Science Magazine.