Heart rate in crossfit and running

Question

I am confused about my heart rate and the sensation I have when exercising. I have been exercising for one year and 4 months, I am 27 seven years old.

I have been doing mainly cardio, but three months ago I started to do crossfit. I always use a heart rate monitor when exercising. My resting heart rate is close to 45 (according to the hr monitor, and measure by myself is below 48). My confusion comes from this: when I do crossfit, I get my heart rate up to 178 and then I feel a very hard breathing. But when running, I get my heart rate up to 175-180 for 25 min and my breathing is heavy, but not even close to what I feel like when I do crossfit. Actually, I start to feel that very hard breathing only if my heart rate gets close to 190 (when running intervals).

I have tried to do measures by myself, and they are close to the previous I mention (except for running intervals, its harder to measure by myself), so it seems that the monitor is working ok(or at least not bad). Does any one have an idea of what is going on? I just want to understand.

Answer 1

Your maximum heart rate depends considerably on the activity. I haven't done crossfit before, but certainly you're involving more muscle groups than running. Biking and running have different HR zones because of weight-bearing vs. sitting. I suspect your HR zones for Crossfit and running are simply different.

It sounds like you're working hard with both workouts. That's the key.

Personally, while I use a HR band, I also go by "perceived effort". The HR zones help me stay in the zones I want, but if I'm breathing hard and sweating a lot, I know I'm getting a good workout regardless of the HR reading.

Answer 2

I agree with Geoff Hutchison, but I also have to add that an exercise you don't know or you haven't done many times are always more physically demanding than an exercise which you perform for years, because your body remembers movements, so it seems easier to you.

Answer 3

The answer is simple, you lifting weights in crossfit. In the 80s studies were done to see if circuit weight training increased stroke volume and vo2max. All studies indicated it did not and stroke volume per heart beat decreased. To compensate for lower stroke volume the heart has to beat faster, hence your have a higher HR during "intense" weight training, i.e. training with short to no rest intervals. This why pro crossfitters cannot escape doing low intensity cardio and anaerobic threshold training, if they want to be elite.