A YouTube video on health by U of T professor and doctor Mike Evans recently reached over a million hits. The video was uploaded in December and became popular on Twitter and Facebook.
In the video, he describes a longitudinal aerobics study by Steven Blaire, a professor at the Arnold School of public health in the University of South Carolina, which found that a number of deaths could be avoided by eliminating “typical risk factors”, such as hypertension, high cholesterol, and diabetes.
The factor that brought the most risk is what Evans calls the “mysterious CRF factor”, cardiorespiratory fitness (which simply means “poor fitness”). Blaire’s study suggests that poor fitness is the strongest predictor of death.
He mentions that most studies have been funded by pharmaceutical companies, and that it’s nice to see a trial that’s not driven by business.
Evans highlights that the study is particularly interesting because of two important findings of another trial, in which Blaire showed that obesity combined with no exercise is extremely detrimental to health. He also discovered that if an obese individual is active, then regardless of any weight loss, the activity will negate many of the harmful consequences of obesity.
Since the studies found a big difference from individuals who started from no activity to a small amount of activity in their life, Evans poses the question, “If exercise is the medicine, what’s the dose—how long, how often, and how intense?” His answer is a personal one, based on his own interaction with patients in his clinic. He emphasizes the need to “think about your style, habit, and personal cues”. Evans says that 30 minutes of activity a day is the optimal amount. The greater the amount of activity the greater the impact on your health, but not always the better.