The interesting part for me was the claim that brief, intense exercise was actually less dangerous than low-intensity, more prolonged exercise for the elderly.

The interesting part for me was the claim that brief, intense exercise was actually less dangerous than low-intensity, more prolonged exercise for the elderly. That's not intuitive, to me -- I would have assumed that old folks should avoid sudden bursts of exercise (as "shaking things up" all of a sudden might provoke a heart attack or stroke). I assume they'd still need to choose their activity carefully to avoid falls (particularly for osteoporosis or other known problems), but that's a separate question, and manageable with a little planning.