European Stars and Stripes (Newspaper) - August 03, 1993, Darmstadt, Hesse                                It of the animal world he cheetah is the Only animal that can run faster than the pronghorn Antelope but it has less endurance. Not by Natalie Angier the new York times o the recreational joggers of the world Champion runners like Carl Lewis and Olga Markova Are the anointed children of zeus cardiovascular demigods who seem to ignite the air molecules around them As they race. Yet even the most elite human athlete is thoroughly pathetic compared with nature s other aerobic masters. Take the pronghorn Antelope of Wyoming for example a Goat sized ungulate that May rank As the greatest athlete alive its maximum Speed of 60 Mph is second Only to the cheetah s top Pace of 70 Mph. But while the cheetah can. Sprint for just a few seconds before practically collapsing the pronghorn can maintain its freeway stride for an hour. When migrating Between California and South America a Hummingbird will Fly for 24 hours at a stretch All the while beating its wings thousands of times each minute. In so doing the tiny creature Burns up such huge volumes of oxygen so efficiently that it would take a human athlete working for a week at Peak capacity without a moment s break to match the Hummingbird s aerobic performance. \ the world s smallest mammal the etruscan shrew is j almost As Light As a dime and yet it can run More than j half As fast As the fastest human. Were it scaled up to 1 human dimensions it would dash through a mile in Abonit 40 seconds. Such Are the conclusions that physiologists reach when they compare the aerobic capabilities of extremely athletic animals with those of people. Naturalists have Long been impressed with the swoops soars dives and dashes displayed by the creatures they study but Only lately have researchers begun to understand the physiological basis of the animals feats. They have Learned How the hearts lungs and circulatory systems of aerobic stars like the pronghorn an a the Blue Fox differ from those of such rutabagas of the animal kingdom As the 100-Pound capybara a 4-Foqt Long South american rodent that James h. Jones a physiologist at the University of California at Davis describes As a big Ball of  some of the recent results in the Field of comparative physiology were presented recently at a meeting of the american lung association in san Francisco. Speaking la an audience of clinicians concerned largely with human respiratory ailments the physiologists emphasized How much could be Learned about human Anatomy and performance by considering the cardiovascular prowess of other species. Many of the latest studies focus on oxygen transport the journey of a breath of air As it passes Down the trache a and into the lungs through the capillary Walls of the Lun and into the blood and from the blood into the Muscles where the oxygen is transformed into Energy. Animal performance depends on Many factors beyond oxygen use including muscle mass skeletal strength and limb length but it is the relative efficiency of oxygen metabolism that accounts for the Streak of a stallion or the sluggishness of a Porcupine. If you re trying to understand How the oxygen transport system really works and you restrict your Studi a to humans you la see maybe a difference of Only 5 or 6 percent Between a sedentary person and an athlete a d Jones a leading figure in the Field. But when you Start comparing systems Between animals you come up against differences of fivefold or tenfold and those Are much easier to measure and to  comparative studies have also revealed where the limits to human athletic achievement May lie. Scientists have found for example that the lungs May be the biggest bottleneck to improved performance in sports. The heart can grow larger with training and thus can pump More blood around the body. The greater the volume of blood the More oxygen it can pick up from r lungs and take to the Muscles where it is needed. I addition a rigorous training program will induce the abundant sprouting of new capillaries to More efficiently deliver oxygen Rich blood to the Muscles. But the lungs themselves do not grow or improve with exercise and eventually their fixed Structure May be what holds Back the swiftest possible transit of oxygen from the air Vas and into the bloodstream. The lungs of an elite athlete and the lungs of a Couch 18 the stars and stripes tuesday