Research (Gill et. al. 2007) reveals that reported measures of exercise intensity “…show the median level of vigorous-activity is consistently ZERO minutes.”
Read that again… zero minutes. That doesn’t even take into account high-intensity activity, which is more intense than the vigorous-intensity activity alluded to in the survey. “…the median level of vigorous-activity is consistently zero minutes.”
So why is this so worrying? What’s so important about intensity?
Intensity is the single most important variable in maximising the health benefits of exercise.
Take note, intensity NOT duration is the most important variable. We live in a volume obsessed physical culture. We value quantity of exercise over quality of exercise. This is a result of both a desperate clinging to outdated research of a bygone era and an aversion to departing from the comfort zone.
So what is intensity? The definitions are numerous. Laboratory bound Exercise Physiologists would use METS (metabolic equivalents), percentages of maximum heart rate, heart rate reserve, or VO2 max. All great lab based measures – but with real world limitations.
Intensity is the amount of work you do in a certain amount of time. How much load you move (whether it be your body weight or an external object), how far you move it, and how quickly you move it. Moving large loads, long distances, quickly.
Intensity is a relative term. If you move a larger load and longer distance, more quickly, you do more work. Your intensity is higher. For you… move the largest load YOU can, the longest distance YOU can, as quickly as YOU can.
Remember of course than intensity is inversely related to duration. The longer the duration, the less the intensity. Australians indicate that time is the biggest factor standing in the way of exercise. Intensity can simultaneously remove our biggest barrier to exercise, while increasing the health benefits of this exercise.
Let’s turn to the research to show just how important intensity is.
“…intensity of physical activity is inversely and linearly associated with mortality.” (Warburton DE, Nicol CW, Bredin SS. Health benefits of physical activity: the evidence. CMAJ. 2006;174:801–809).
“Improvement in insulin sensitivity after six months combined supervised group training in female diabetic subjects is related to exercise intensity…” (Dunstan DW, Daly RM, Owen N, Jolley D, De Courten M, Shaw J, Zimmet P: High-intensity resistance training improves glycemic control in older patients with type 2 diabetes. Diabetes Care25 :1729 –1736,2002).
“Light activities were not associated with reduced mortality rates, moderate activities appeared somewhat beneficial, and vigorous activities clearly predicted lower mortality rates. These data provide some support for current recommendations that emphasize moderate intensity activity; they also clearly indicate a benefit of vigorous activity.” (Lee IM, Paffenbarger RS Jr. Associations of light, moderate, and vigorous intensity physical activity with longevity. The Harvard Alumni Health Study. Am J Epidemiol 2000;151:293-9).
A disclaimer. Anything is better than nothing. Generally, sprinting is better than jogging is better than walking is better than standing is better than sitting is better than lying. But that being said, walking (though not as good as sprinting) is WAY better than lying. Something is always better than nothing. Even if that something is the most ineffective form of exercise imaginable, it is light years better than the sedentary alternative. Just remember that it’s a continuum. There’s a better way. Work your way up this continuum and give intensity the effort your health deserves.
