Body by Science

Moreover, because running for long periods burns primarily fat, technically, he’s not tapping his glycogen stores to any significant degree, with the result that his insulin sensitivity is going to go down over time with this type of behavior. That’s going to put him at increased risk for coronary disease—the very thing that he foolishly believes he is taking steps to alleviate by engaging in his low-intensity, steady-state activities.

If the intensity of exercise is too low, nothing much in the way of a stimulus is presented to the body.

The key findings in these studies indicate that in terms of overall health, a workout requiring six to nine minutes a week produced the same muscle enzymes (which are essential for the prevention of type 2 diabetes) as a workout requiring four and a half to six hours per week.

from a health and fitness standpoin

Given the large difference in training volume, these data demonstrate that SIT is a time-efficient strategy to induce rapid adaptations in skeletal muscle and exercise performance that are comparable to ET in young active men.'

In fact, they received “zero” additional benefit from all of the extra time they spent engaged in exercise.

Despite the fact that the more conventional endurance exercise group spent 97.5 percent more time engaged in exercise, both groups of subjects were found to have improved to the same degree.

because it suggests the overall volume of exercise people need to do is lower than what’s recommended

been long ago proven wrong

It appears that this is the first scientific documentation that very intense sprint training in untrained people can markedly increase aerobic endurance and that the total “dose” of exercise over the 2-wk period, performed in six sessions, amounted to only 15 min.