I've heard both. Guess it depends on who you talk to. As far as your health goes, they now say that it can be split up. Not sure about exercise for weight loss but I think the longer you go the more your heart rate goes up and the more calories you burn. But that's just my guess. Someone else probably would know more about it. Anyone?

Frances

I've heard that breaking it up is better for weight loss, and that doing it in 10 minute spurts is better then all at once. I'm not sure though, I've always been one to start it and get it over with, 'cause once I stop, there's no starting again.

Hmm... well, I heard the importance isent really in the calories your burning while your working out... Its the fact that when your muscles are more fit and exercised, they burn more calories when your dormant. I mean, 40 mins on the bike machine only burns about , say, 160 calories (on easy mode :P). Trying doing some simple weight lifting, get your muscles in shape. I went out and bought 2lb free weights. Keep em by the phone so if someone calls i can just do silly things at the ttime ^_^...

I just like to do it and get it over with since I'm usually walking. Although when doing weights I've found that if you do them slower, you don't have to do as many reps.

If you're wanting to exercise for the sole purpose of burning calories, working out for any duration of time will do.

However, to improve your cardiovascular health, which, really is more important than simply burning calories, you need to work out for 30 minutes (or more) and keep your heart rate up for most of that time.