2. TRUE OR FALSE: Resting heart rate is a good indicator of aerobic fitness. continued...
"For most people, a normal resting heart rate is between 60 and 90 beats a minute," Coyle says. "Athletic training can lower that rate by 10 to 20 beats per minute."
But if you have a lower resting heart rate than someone else, don't assume that you're in better shape than them, or vice versa. Two people can be equally fit and have significantly different resting heart rates.
"Both a couch potato and a highly trained marathoner could have a heart rate of 50 to 60," says Benjamin D. Levine, MD, professor of medicine and cardiology at the University of Texas Southwestern Medical School and director of the Institute for Exercise and Environmental Medicine, both in Dallas.
3. TRUE OR FALSE: Maximum heart rate declines with age.
TRUE. As we all know, exertion makes the heart beat faster, and the greater the exertion, the faster the heart rate. But there's an upper limit on how fast your heart can beat, and that limit is affected by age.
"Maximum heart rate is unrelated to exercise training," Hirofumi Tanaka, PhD, tells WebMD. He's an associate professor of kinesiology and health education at the University of Texas and director of the university's Cardiovascular Aging Research Laboratory.
"Whether you're a couch potato or a highly trained athlete, that rate declines about seven beats per minute for each decade," Tanaka says. Regular exercise can lower your resting heart rate, but it does nothing to slow the age-related decline in maximum heart rate.
4. TRUE OR FALSE: Moderate exercise promotes weight loss more effectively than vigorous exercise.
FALSE. Weight loss is a matter of simple arithmetic: To shed pounds, you must burn more calories than you consume. And when it comes to burning calories, the greater the exertion, the greater the rate at which calories are burned.
Working out at about 60% to 75% of your maximum heart rate (the so-called "fat-burning zone") burns fewer calories than working out at 75% to 85% of your maximum heart rate (the so-called "aerobic" or "cardio" zone).
But caloric burn depends on a workout's duration as well as its intensity -- and it's easier to work out longer when exercising at a lower intensity.