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.

In Santiago, What’s Smog Got to Do with It?


Smog hangs over the city of Santiago, Chile. Credit: Anne Crecelius

Upon arriving in Santiago, Chile, my travel companions from the University of Dayton and I were struck by the beautiful sights of the Andes mountains and the not-so-beautiful sight of a cloud of smog hanging over the city.

Like many major metropolitan areas, such as Los Angeles or Mexico City, the city of Santiago (population ~8 million) suffers from poor air quality. Typical contributors to pollution, such as dust and automobiles, are part of the problem, but Santiago also has a geological disadvantage. The city is located in a valley between the beautiful Andes mountains and the Pacific Coast, which often causes polluted air to “settle” in the city. Frequent thermal inversions—where cold air settles beneath warm air—amplify the smog problem, especially in the winter months (June through August in the Southern Hemisphere).

A recent study linked millions of deaths to air pollution in Asian countries. But what makes air pollution so bad for our bodies? Different pollutants can have different effects on each of the body’s systems. Depending on the size and amount of pollutants in the air, particles can irritate our lungs or even enter our bloodstream. Once in the blood, toxins can negatively affect multiple organs such as the lungs, heart, brain and liver.

So what are the residents of Santiago, or visitors like me, to do?

Keep Preexisting Conditions in Mind

People with existing conditions that affect the ability to breathe are at increased risk of problems caused by high smog levels. For example, my colleague who has asthma had to be extra careful and used her albuterol inhaler frequently. Albuterol is a medicine that acts on the passageways of the lungs to help them open and allow air to flow more easily.

Exercise with Caution

If air quality is exceptionally poor, such as during a thermal inversion, take extra caution when exercising outside, or consider indoor options.

Share the Road

Using public transportation, biking and walking can help reduce vehicle emissions. If you are around high-traffic areas, you still may want to cover your face to protect yourself from the larger particles in the air. While walking around the city, I observed many Chileans using this method.

My colleagues may not have taken notice, but I thought “I spy physiology!”

Anne Crecelius


This post is part one of a three-part series by physiologist Anne Crecelius, PhD, chronicling her summer of research and travels through South America. Crecelius is assistant professor at the University of Dayton.

Physiology Is Alive and Well, Just Ask an Undergraduate Student

Undergrad Poster Session at EB16

Physiology Undergraduate Poster Session at Experimental Biology 2016

When you think of a cutting-edge, exciting area of science, do you think of physiology? If not, you should. Physiology is the basis for medicine. Many important medical advances that we take for granted today are direct or indirect results of research conducted by physiologists. But despite the significance of our area of research, some universities are removing physiology from medical school curricula, shutting down physiology departments or calling them by another name. Not surprisingly, this causes a great deal of angst among physiologists and is often discussed in our community.

Luckily, physiology is flourishing at the undergraduate level. Despite a smorgasbord of options for college majors in life science disciplines—including bachelor of science degrees in genetics, biochemistry, cell and molecular biology, integrative biology, etc.—more universities have started to offer physiology as a stand-alone undergraduate major instead of  offering only a course on physiology. While the major has existed in a few isolated cases for many years (e.g., University of Arizona and Michigan State University), the past decade has seen many new programs added and the conversion of several programs from kinesiology to human physiology with 43 programs in the U.S. today. These programs typically have seen three- to five-fold increases in enrollment over the past five years.

Recently, we published a paper on the millennial student view of physiology. We found that:

  • 78 percent of physiology majors have preferences for studying whole-body physiology (with 67 percent interested in integrative/systems physiology and 11 percent interested in integrative and cellular physiology);
  • students interested in cell- and molecule-level function are gravitating to other majors such as biochemistry and genetics;
  • student interest in integrative physiology is aligned with
    • interest in an applied and holistic view of human health and disease and
    • student aspirations for careers in health care; and
  • physiology programs are the primary pathway for students heading into medicine, physical therapy and other allied health professions, with 85 to 90 percent of students in a physiology major stating career aspirations in health care.

Considering these findings, one thing seems clear: Millennial undergraduate students intuitively understand that physiology is the basis for medicine. They know that choosing a major in physiology is the best way to learn more about the human body. In my opinion, physiology is alive and well; you just have to know where to look.


Wehrwein_Erica 2009

Erica A. Wehrwein is an assistant professor at Michigan State University.  She leads the Physiology Majors Interest Groups (P-MIG), a consortium of physiology undergraduate programs.

Pop Quiz: Test Your Physiology Knowledge!

PIO Quiz Image

Take our physiology quizzes!

If you’ve been following along with the I Spy Physiology blog, you may be feeling like a physiology wiz. APS member-physiologists have developed a series of quizzes to help you test your physiology smarts and, perhaps, teach you something new. Visit www.physiologyinfo.org to take one of our systems quizzes (cardiovascular, digestive, endocrine or respiratory) or check out our general physiology quizzes (part 1 and part 2) that test your knowledge of physiological functions throughout the body. Share the quizzes with your friends and colleagues to compare scores, and remember to check back often for new quizzes as they’re posted.

Happy quizzing!

Stacy Brooks

Not in the Same Vein

Human circulatory system, full figure, cutaway anatomy illustration.

Human circulatory system. Credit: IStock

The word “vein” pops up in a variety of contexts. When used as a figure of speech, vein means similar or alike, for example “in the same vein as.” But in the body, vein refers to a specific type of blood vessel.

Encyclopedia Britannica defines blood vessel as “a vessel in the human or animal body in which blood circulates.” Though they may be structurally similar to the two other types of blood vessels—arteries and capillaries—veins have a unique and important role in circulation.

When the heart contracts, it pumps out oxygen-rich blood that first passes through arteries, then into capillaries—the location where oxygen is sent out to the body and carbon dioxide and other waste is picked up. The deoxygenated blood then travels through the veins back to the heart. The whole process takes just 20 seconds to complete. (WATCH this cool real-time animation of the red blood cell cycle.)

While veins are primarily responsible for moving oxygen-depleted blood back to the heart, this is not always the case. The amount of oxygen in the blood carried in the veins varies depending on whether they service the lungs (as part of pulmonary circulation) or the rest of the body (as part of systemic circulation). In systemic circulation, arteries carry oxygenated blood to the organs, and muscles and veins carry deoxygenated blood back to the heart. In pulmonary circulation, the process is reversed. The arteries carry oxygen-poor blood to the lungs, while the veins deliver newly oxygenated blood to the heart.

Veins and arteries also look different. Arteries control blood flow and pressure, so they are muscular to narrow and widen (dilate) effectively. Veins are less muscular than arteries and have thin, stretchy walls, which is why you can see them bulge out of your arms and hands. Because the blood pressure in the veins is lower and the blood is often moving against gravity, most veins also have valves to ensure blood flows in only one direction.

So when it comes to blood vessels, differences in their look and function demonstrate that they are not in the same vein.

Maggie Kuo and Stacy Brooks

Let Your Moves Turn Back the Clock on Aging

Group of people dancing in dance class

Credit: IStock

Do you think someone could guess your age? If so, how would they do it? Guessing a person’s age can be a challenge for a number of reasons. Just looking at someone is not always a reliable gauge—two 52 year olds, for example, may not look and act the same. Understanding the differences in how people age is important, especially because aging is a major risk factor in the development of many chronic diseases.

There is a growing interest in studying how to slow aging. The point is not just to make everyone live longer, but rather to extend the number of healthy, disease-free years throughout the lifespan. Scientists refer to this disease-free time as the “healthspan,” to reflect the extension of time spent healthy. A team of researchers recently started the Geroscience Initiative—a research project based on the premise that slowing the aging process can help us simultaneously treat most major chronic diseases. Because age is the No. 1 risk factor for heart disease, cancer, type II diabetes and others diseases, slower aging could lead to later disease onset and a longer healthspan.

According to a recent article, movement might be the best measure of aging across many species, including worms, flies, mice and humans. Movement is a good measure because it is complicated and involves coordination of balance, brain, strength, energy production and communication between diverse areas of the body. With advancements in laboratory technology and wearable measurement devices for humans, it is becoming increasingly possible to measure movement objectively in many different species. Once enough data are captured on movement, we might be able to better use the ability to move or the amount of movement as a measure of aging.

Although the concept of increasing the healthspan is attractive, it has been difficult to document healthspan increases because there are not universal markers for aging. Therefore, measures such as movement become important to determine if we are effectively slowing aging and therefore decreasing the risk of most chronic diseases. An unintended bonus of tracking movement is that it stresses how vital activity, in all its shapes and forms, is to maintaining health. So keep moving and add more health and life to your years.

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.

Learning about a Leading Cause of Infant Mortality from Lambs

Crying Baby

Credit: Wikimedia 

Pulmonary hypertension is a form of high blood pressure that affects the blood vessels in the lungs. In the womb, the blood pressure in the fetus’ lungs is normally high. Once a baby is born, there is a switch from a high to low blood pressure. When this fails to happen, the baby develops pulmonary hypertension.

Pulmonary hypertension occurs in about six in 1,000 newborn babies each year and may occur more frequently at high altitudes. Despite all of our recent advances, many infants do not respond to treatment and as many as 33 percent of these babies die. Because current treatments are not entirely effective, many groups of researchers are working to find new treatments.

In a recent article, Chilean researchers observed 10 lambs that were conceived and born at high altitude, which causes pulmonary hypertension, and compared them to lambs born at a low altitude. The goal was to see if giving a drug called fasudil to young lambs would reduce the development of pulmonary hypertension in the high-altitude lambs.

Fasudil targets a molecular pathway known as the RhoA/ROCK pathway, which is thought to play a major role in causing pulmonary hypertension. Previous studies have shown that fasudil lowers lung blood pressure in adults, but it wasn’t known whether the drug would also work in infants. The researchers in this study found that fasudil opened up (dilated) lung blood vessels in the lambs born at high altitude and lowered pulmonary blood pressure. The results show that fasudil and other drugs that intervene on the RhoA/ROCK pathway have the potential to decrease pulmonary hypertension in infants, too. These drugs may be a new tool in a physician’s arsenal, possibly preventing death and other serious complications in babies born with pulmonary hypertension.


Rachel Luehrs is a graduate student in the Bates Laboratory of Pulmonary and Developmental Physiology at the University of Iowa.

How Many Hot Dogs Can You Eat in 10 Minutes?

Junk Food

Credit: iStock

The competitive-eating elite will descend on New York City’s Coney Island this Fourth of July to flex their hot dog eating skills at the annual Nathan’s Famous Hot Dog Eating Contest. Last year, the male winner ate 62 hot dogs and the female winner ate 38 hot dogs in 10 minutes. Competitive eaters are surprisingly slight for the enormous amount of food they are able to consume. Where do all those hot dogs go?

The stomach is not a passive sack but an active organ that expands and contracts. An empty stomach holds about 1/4 cup, but when a meal is swallowed, the stomach expands to hold as much as 6 cups without stretching its walls. Besides relaxing to hold the meal, the stomach’s walls squeeze in and out and back and forth to move the food into the intestines, a process called gastric emptying. Researchers at the University of Pennsylvania wondered if speed eaters’ ability to keep down so many hot dogs was because their stomachs emptied faster or if their stomachs were trained to hold much more food than the average person.

The researchers recruited a professional speed eater and compared his gastric physiology to an individual with a big appetite. A gastric emptying test revealed that the professional speed eater’s stomach emptied slower than the regular eater. After 10 minutes, the regular eater consumed seven hot dogs, and his stomach was not stretched out. In contrast, the speed eater ate 36 hot dogs, and his stomach became a “massively distended, food-filled sac occupying most of the upper abdomen,” the researchers wrote. While the regular eater felt sick, the speed eater said he didn’t feel full, leading the researchers to wonder if the competitive-eating training made the stomach so stretchy and limp that the competitors never get the “full” physiological signal.

Although the study examined only one professional speed eater, the results support the idea that competitive speed eaters could eat large amounts of food in short periods of time not because their stomachs emptied faster but because their stomachs were able to enlarge dramatically.

The record for most hot dogs eaten is 69. How does the stomach look after that many? Not great, this video from ESPN shows.

Maggie Kuo

Looking for a New Physical Challenge? Try a Mountain Ultra-Marathon

Idyllic Alps Valley

The Aosta Valley in Italy where the Tor des Geants is held. Credit: iStock

Of all the extreme endurance races out there—such as the Ironman triathlon or 50- or 100-mile marathons—the Tor des Géants ultra-mountain marathon may be the most extreme. The course is 205 miles long on the rugged terrain of the Italian Alps with a cumulative elevation gain of 24,000 feet. Participants have 150 hours, little more than six days, to complete the course. These feats of ultra-endurance are fascinating for scientists because they showcase how the heart adapts when pushed to the limit. Previous studies have found that after 3- to 15-hour races like marathons and the Ironman triathlon, the heart doesn’t pump as well, a condition referred to as exercise-induced cardiac fatigue. A group of French researchers looked at what happened to the heart after running for over 100 hours in the Tor des Géants. They were surprised to find that unlike with marathons and triathlons, heart function improved after the ultra-mountain marathon race.

During a heartbeat, the heart fills with blood and then squeezes together to push out the blood. In situations in which the body constantly needs more oxygen, such as with exercise, the amount of blood filling the heart is one signal that tells the heart to keep beating harder. The more the heart fills, the stronger the heart contracts.

This study found that the runners’ hearts filled more during each heartbeat. The researchers think it’s because the amount of plasma, which is the liquid portion of blood, increased, raising the overall amount of blood in the body. But why it increased is not clear. Fluid intake could be one factor, says Michael Joyner, MD, an exercise physiologist not involved in the study, in a podcast. Runners in ultra-long races pay extra attention to staying hydrated and often maintain or gain weight from the extra fluids, he says. Stéphane Nottin, PhD, the lead investigator of the study, wonders if inflammation from the extreme physical stress or greater retention of sodium (the kidneys use sodium to absorb water) is also involved.

“Physiology has a long history of expedition-led investigations—whether it’s high altitude, desert—and this paper follows in that wonderful tradition,” Joyner says. Other current ongoing studies in this spirit include a Mount Everest climb to examine cognitive decline at low oxygen levels and a study on the heart of a swimmer swimming across the Pacific.

Maggie Kuo

The Antioxidant-Activity Connection

Strawberries and Blueberries Background

Credit: iStock

Antioxidants: It’s one of the biggest health buzzwords today. The fabled powers of these mysterious compounds have been featured on daytime TV, plastered on age-defying beauty products and foods in the grocery store, and sold to us as a major reason to frequent juice bars and smoothie shops. Antioxidants are not just an overblown fad, though. They play an important role in keeping our bodies healthy, and they are critical for some people, such as patients with chronic obstructive pulmonary disease (COPD), who can’t get enough oxygen and are inactive as a result.

Antioxidants neutralize molecules called reactive oxygen species (ROS). ROS compounds are byproducts of our body’s metabolism, and too much of them can damage DNA, change cell structure and even kill cells. We can acquire antioxidants to combat ROS by eating foods such as berries, nuts and sweet potatoes. In addition, the body has its own array of natural antioxidants to destroy ROS. Inactivity and low oxygen in the blood (hypoxia) that occur in COPD alter the body’s levels of ROS and antioxidants and can worsen the disease. Maintaining healthy levels of ROS and antioxidants in patients with COPD is a concern for health care providers.

A new study published in the Journal of Applied Physiology found that a low level of activity may be enough to raise antioxidant levels. In a 10-day study, healthy women were confined to strict bed rest, confined to bed rest while breathing air with 32 percent less oxygen, or breathed the low-oxygen air but could stand, walk and conduct normal daily activity. Blood samples were taken before, during and after the experiment to compare the balance between ROS and antioxidant levels. ROS levels increased in all three groups, but the most noticeable difference was in the active group, which had higher antioxidant levels than those on bed rest. Although low oxygen in the blood increased the ROS levels of the participants in the active group, maintaining a somewhat active lifestyle allowed their bodies to produce more antioxidants to buffer the damaging ROS compounds.

There’s a growing population of patients with lung disease who experience both inactivity and hypoxia, so research that helps identify additional consequences of hypoxia and inactivity is paramount for improving care. This study suggests that if these patients can maintain some degree of their physical routine, they may be protected from some of the damaging effects of ROS. This research also provides evidence health care workers can use to educate and encourage healthy behaviors in their patients to reduce complications caused by too much ROS.

Thomas J. Otskey, Hannah Grace Deery, Sandra Bigirwa, Sarah Small and Erin Feldott are students in the Department of Health and Human Physiology at the University of Iowa studying respiratory physiology with Melissa Bates, PhD.