sean

Hi px--

The contradictory reports you've gotten both have some kernel of truth--they are looking at different aspects of the issue.

As far as I can tell from the recent studies, interval training--short, very intense spurts mixed into longer stretches of easier, more aerobic activity, can indeed burn more calories in a half hour or so than can an hour of sustained, more regular, aerobic exercise. There is also evidence that kicking the system up into high intensity mode, even for short spurts, is more likely to lead to increased metabolic calorie burn for more hours after the exercise than longer, less intense exercise, even if the total quantity of the latter is much greater. This metabolic burn rate lasts for hours, or in some lucky people, all day and right into sleep mode.

On the other hand, despite expectations, neither high intensity interval exercise, regular exercise, nor resistance exercise resulting in greater muscle mass have been shown to produce the greater "permanent" metabolic increase--resting metabolic rate--that everyone expected to find when the studies were launched. That is, higher burn rate lasting for more than hours--persisiting even when the person has not exercised for days or weeks. The only studies I am familiar with that have conclusively found more or less permanent higher resting thermic levels (higher metabolism) have found it in people who have done extended endurance exercise and for a long time. People who've been jogging or running or cycling or the like, for several hours per week, and for years.

ALL the exercise burns calories, ALL (except the most severe) leads to greater health, better fitness, etc. So, why worry so much about these esoteric findings related to very specific types of activity? Do whatever you like best, and do as much of it as you can fit into your life comfortably. That way, whatever regimen you adopt, you are likely to keep at it, or even add to it as time goes on.

That's what'll be best, in the end.

sean