Life Lines - The Podcast of The American Physiological Society

APS’ Chief Science Officer Dennis Brown, PhD, recently spoke to astronaut and APS member Jessica Meir, PhD, about her work on the International Space Station. As part of the interview, we asked her for lessons that #StationLife can teach us about living in isolation. Listen to her recommendations and read the full interview in the July issue of The Physiologist Magazine.

Heart attacks peak during the winter months and cold weather has been thought to be the primary culprit. But cardiologist Robert Kloner of the Keck School of Medicine and Good Samaritan Hospital found that heart attack deaths peak on Christmas and New Year's in the mild climate of Los Angeles County. Could it be that the weather is not the most important factor behind the seasonal increase in heart attacks?The show's second segment, the Buzz in Physiology, features research on how a probiotic treatment alleviated colitis in mice and how five exercises helped women office workers suffering from repetitive strain injury. (Begins at 10:55)From the American Heart Association, Heart Attack/Stroke Warning Signs. Click here.Total Time: 13:28

What would it be like to live without being able to detect any odors? For one thing, Thanksgiving would be much less enjoyable, perhaps disturbingly so. In this episode, we talk to Robert I. Henkin of the Taste and Smell Clinic in Washington, D.C., who will tell us why people lose their sense of smell and how his research can help some people restore it. (Begins at: 02:03)The Buzz in Physiology features studies on a simple test that may determine arterial stiffness in adults older than 40, and a look at a 1950s program that tested the fitness of women to become astronauts. (Begins at: 00:43)

Dean Franklin developed the first instruments to measure blood flow and the changes in diameter of the pulsating heart in conscious animals. He also pioneered the use of radio waves to measure heart and blood vessel function without wiring the body to the instrument. Dusty Sarazan, a former student of Dean Franklin, explains how these inventions led to the non-invasive cardiovascular monitoring instruments we have today. You can find the full article on Dean Franklin here and a press release here. (Begins at 02:22)A program note: We misspoke when we mentioned that physiologists made an important discovery after a giraffe frightened an instrumented baboon. In fact, a leopard had frightened the baboon.The Buzz in Physiology(Begins at 00:52) A study on how exercise helps prevent weight regain after dieting finds that exercise reduces the drive to overeat, causes the body to burn fat before burning carbohydrates and prevents an increase in the number of fat cells during weight regain.A study on how alcohol can disrupt circadian rhythm finds that chronic drinking blunts the biological clock's ability to synchronize daily activities to light, disrupts natural activity patterns and continues to affect the body's clock even days after the drinking ends.

You've heard the word telecomm? In this episode, we are going to coin a new word: elecomm, shorthand for elephant communication. Caitlin O'Connell-Rodwell is a Stanford University professor and the author of The Elephant's Secret Sense, published by the University of Chicago Press. Dr. O'Connell-Rodwell discovered that elephant vocalizations travel through the ground, sometimes for great distances. Other elephants pick up these seismic communications and understand them. There are links to videos of three of Dr. O'Connell-Rodwell's elephant communication experiments on her website, www.utopiascientific.org or by clicking here, here and here. (Begins at 2:44)From the Buzz in Physiology (Begins at 1:13): Divers who held their breath for several minutes had elevated levels of S100B (a protein found after cell injury) in their bloodstream, which suggests that holding one's breath for a long time disrupts the blood-brain barrier. However, the appearance of the protein was transient and leaves open the question of whether lengthy breath holding can damage the brain over the long term, according to the Lund University researchers.And drinking beetroot juice boosts stamina and could help you exercise for up to 16% longer, according to a study from the University of Exeter. The study shows how the nitrate contained in the juice leads to a reduction in oxygen uptake, making exercise less tiring.You can read the press releases on these studies: FreedivingBeetroot

Episode 24: Pregnancy and ExerciseWhen a pregnant woman exercises, is it good for her fetus? That is the question that researchers Linda May of the Kansas City University of Medicine and Biosciences and Kathleen Gustafson of the University of Kansas Medical Center are trying to answer. Their work is ongoing, but it is good news, so far, for pregnant women who like to exercise. (Begins at 01:59)Buzz in Physiology (Begins at 00:47)Estrogen can halt the damage caused by a stroke by inactivating the protein, p53. Researchers have found a way to diagnose overtraining syndrome in horses by measuring the secretion of nocturnal growth hormone. 

Three physiologists tell us why the prescription "drink when you are thirsty" is usually the best guideline for deciding when and how much to drink. We will talk to Heinz Valtin of Dartmouth Medical School (retired); Mark Knepper, the chief of the Laboratory of Kidney & Electrolyte Metabolism of the National Heart Lung and Blood Institute; and Samuel Cheuvront, of the Thermal and Mountain Medicine Division of the U.S. Army Research Institute of Environmental Medicine about water consumption. They will answer the question: "Must I drink 64 ounces of water each day?" (Begins at 3:47) To read the review of the eight-by-eight rule by Heinz Valtin, click here: In the Buzz in Physiology, we look at studies involving a prosthetic device known as the Cheetah Flex Foot and whether it gives a runner who is a bilateral amputee an unfair advantage over limb-intact runners. We also summarize a study in mice in which adult bone marrow stem cells were used as a non-invasive therapy to repair cardiac tissue. And finally, we'll look at a study that finds that electro-acupuncture successfully reduced sympathetic nerve activity, normalized menstrual cycles and reduced testosterone in women with polycystic ovarian syndrome. (Begins at 1:05)

There is nothing like a good laugh, is there? It not only feels great to laugh, it can feel great to hear other people laugh. Beyond brightening the mood, can laughter provide tangible health benefits?Lee Berk of Loma Linda University in California has done a series of studies on laughter and its possible physiological effects. We will talk to him about his latest study, done over the course of a year with diabetic patients. (Begins at 3:50)In this month’s Buzz in Physiology (begins at 0:51), we look at studies that provide possible explanations for:

Total Time: 9:47

Did you know that there is a sensor in the nerve endings in the carotid artery that rapidly lowers blood pressure when stimulated? This discovery may one day allow people who are hypertensive to lower their blood pressure by using a pacemaker-like device that stimulates the nerve endings in the blood vessels.In this edition of Life Lines, we talk to Francois Abboud, of the Carver College of Medicine at the University of Iowa whose research identified this sensor. We’ll also talk to him about his recent research looking at the genes that regulate ion channels, microscopic gates that move chemicals in and out of cells, and that play a role in the signaling between the brain and the blood vessels. In experiments with animals, Dr. Abboud and his colleagues deleted one specific ion channel and found that the animals developed high blood pressure. (Begins at 03:51)We'll also talk to Ann M. Schreihofer, of the Medical College of Georgia, who focuses on the role the brain plays in increasing sympathetic nervous activity, which contributes to many forms of hypertension (high blood pressure). Among the questions her research seeks to answer is why people who are obese become hypertensive. The Schreihofer laboratory has also been looking at sleep apnea and whether it is possible to improve respiratory function as a way to reduce the sympathetic activity that leads to obesity and hypertension. (Begins at 09:43)In the Buzz in Physiology (begins at 1:24), we have studies on:

The photo in our logo is a neuron from the rostral ventral lateral medulla of the brain stem and was provided by Dr. Schreihofer.Total running time: 16:45.