Exercise Intensity: Does It Really Matter? Part 2

Just over 2 months ago, I commented on a study that demonstrated that high intensity exercise was associated w/less silent brain infarcts or subclinical cerebrovascular disease.  In yesterday's commentary, a study demonstrated that aerobic exercise was better at fat loss than resistance training.  So I thought that I'd round out the discussion by looking at a small study of just 10 men that concluded that 45 minutes of vigorous exercise (good for 519kcal) increased energy expenditure by 190kcal over the next 14 hours after exercise.

Just how did the authors come to this conclusion?  They locked each person individually in a metabolic chamber that measured baseline oxygen consumption and carbon dioxide production for 24 hours, initially at rest.  The participants' activities were closely monitored such that they either sat or slept for the most part, stretching just 2 minutes every 2 hours, aside from toileting & hygiene.  This was repeated on another day with the exception of 45 minutes of vigorous exercise equivalent to 519kcal.  More importantly, energy expenditure was noted to increase by 190kcal over baseline for the remaining 14 hours after exercise.

This study demonstrates that energy intensity does matter, at least when it comes to energy expenditure (and thus weight loss).  It's better to exercise for a shorter period of time at a higher intensity (at least 73% VO2max) compared to exercising for a longer period of time at a lower intensity.  So think about how hard you're going to push yourself the next time you exercise (you do exercise, don't you?).