You may know Dr. Kenneth Cooper as the most influential advocate of aerobic training as the best way to exercise. “The Father of Aerobics” produced reams of research in the 1970s supporting the positive aspects of steady-state cardio training. Now let’s talk about what the cardio training proponents haven’t told you.
1. Cardio can be harsh on the joints. Certainly, cardio training can improve bone density and thus help prevent or mitigate orthopedic problems such as osteoporosis. But let’s face it – not everyone has a body type suitable for distance running, and for them the risks of running may outweigh the benefits. Further, for an obese person who starts a running program, their excess body weight significantly increases the stress on their joints, increasing the risk of musculoskeletal problems.
2. Cardio success stories are often misleading. Observing a group of fit individuals doing an aerobics class can be misleading – for the simple reason you only see the successes. When someone experiences pain or gets hurt while taking an aerobic class, they simply quit. You also have to factor in that many of these classes include non-aerobic strength training activities, such as push-ups and sit-ups, so the positive results may not be attributable solely to aerobic training.
3. Treadmill running causes muscle imbalances. Running on a treadmill is biomechanically different from normal running. Because a treadmill pulls your foot backward, your posterior chain muscles, such as the hamstrings, do little work. The resulting muscle imbalances can present themselves in postural problems that can contribute to musculoskeletal problems, especially lower back pain. The number-one cause of job-related disability and missed days from work in the US is back pain, according to the National Institutes of Health, and an estimated 80 percent of Americans will experience back pain by the age of 55. Those with a history of back pain should think twice about the benefits of exercising on a treadmill.
4. Treadmills can kill. People fall off treadmills all the time – on YouTube you’ll see plenty of tragic evidence. When the back end of a treadmill is placed too close to a wall or other solid object, the trainee is often flung against the wall. Because many gym owners ignore safety standards or simply are not aware of them, many individuals die each year from striking their head against a wall after falling off treadmills.
5. Cardio is not as effective as diet for weight loss. In a meta-analysis of 493 studies spanning 25 years, it was found that changing one’s diet is a much more effective way for overweight individuals to reduce body fat than doing exercise. However, one problem with doing cardio is that the body becomes more efficient with training, thus reducing the fat-burning effects.
6 .Cardio performed outdoors can increase toxic load. Performing cardio in polluted environments may do more harm than good due to the higher risk of exposure to toxins. Although it’s difficult to determine exact risk-to-benefit ratios of exercising outdoors in polluted environments, people with medical conditions such as asthma and heart disease may be better off doing other forms of exercise indoors.
7. Cardio compromises muscle development. One of the best ways to increase metabolism (the rate at which you burn calories) is to gain muscle. Unfortunately, cardio can compromise muscle gains or, at the very least, prevent increases in muscle. From an empirical standpoint, endurance athletes at the highest levels have very little muscle mass. During the cutting-up phase of pro bodybuilders, it’s no secret that cardio often compromises their gains.
8. Cardio can age you quicker. Runners often joke that if you want to see what you look like in 20 years, run a marathon and then look in a mirror. Here’s a scary fact: Aerobic training increases cortisol levels that can increase free radicals that in turn increase inflammation, which is associated with aging. A study in 2011 in Psychoneuroendocrinology that measured the cortisol levels in 304 endurance athletes found that their training “…is associated with elevated cortisol exposure over prolonged periods of time.”
Certainly any form of exercise is generally better than no exercise, but the health and fat-loss benefits of cardio training are not as great as many fitness celebrities would have you believe. If you like doing cardio and want to do cardio, fine – but you deserve to know the whole truth.