Heart Rate Monitor for Insanity

A heart rate monitor is a really good idea for Insanity, since the goal of HIIT is to get your heart rate up, and then let it come back down a bit before you go back up. Shaun T actually tells you to check your heart rate at water breaks to make sure you're not going TOO hard. So absolutely monitor it to make sure you're not getting into a dangerous zone, and if you are, modify or go slower.

That's really the big reason to use a HRM. Calculating calories burned is really only a secondary reason to use one, and they aren't always accurate. But I found for Insanity my HRM would tell me I was burning a LOT less than the commercials say you will. While the commercials say that you can burn up to 1000 calories, I was somewhere around 400 calories in the 40 minutes-- which is awesome and nothing to scoff at, but it's a good reminder that it's not a miracle calorie burner that gives you a free pass on the extra two pieces of pizza you'll inevitably want (I'm not the only person that's ravenously hungry for the first week I up my intensity, am I?)