Heart rate (weights)

kpsyche

I'm sure this has been asked a million times, but I cannot find a handy thread.

Since I got my fitbit I've noticed that during walking (hiking actually) I spend about 25% of my time in the "cardio zone" (about 125bpm) especially when I am walking downhill after walking up (the other 75% I am in the "fat burn" zone, about 115bpm). I thought my heart rate would be higher walking uphill but maybe it's higher when I'm going down the other side because I'm recovering?

My real question though is weight training. When I do weights about 70% of my time is in the cardio zone, almost 30% in fat burn and maybe 1 min (out of 30 minutes) at "peak zone". For example, today at about 1/2 way through my workout my heartrate was between 150 and 154 for about a minute and then went back down into the mid-120s (mostly) for the rest of the workout. Based on this I seem to do more "work" during weight training then I do when I lift weights than when I'm hiking! Does this seem right? And related to that, should I be logging my weight training as cardio?

Edit:
My graphs won't upload. They're here if they might be applicable: https://imgur.com/a/oHDvt

TavistockToad

A HRM is no use for strength strength, they're for steady state cardio.

amusedmonkey

The mechanism that spikes heart rate when weightlifting is different from the mechanism that spikes heart rate when doing cardio. The relation between calorie burn and heart rate is only correlational and only stands reasonably well (but not perfectly well) for steady state cardio. There is little to no clear correlation between heart rate when lifting and calories burned.

If I were you, if weightlifting contributes too many calories to your activity level due to heart rate, I would keep the tracker on for hikes (since it's counting steps which produce a good estimation of calories burned), but leave it off for weightlifting and log that manually (if you wish).

MeanderingMammal

The relationship between HR and work done is not straightforward I'm afraid. Lots of things affect HR, many of them unrelated to workload.

When you're walking, that's classic cardiovascular activity, where HR is related to volume of oxygen being transported to points of use. That said, at the low end of the aerobic range, where you are when walking, there is not a linear relationship. For a 10bpm difference, that may be as simple as walking faster.

Essentially, don't worry about zone training. It has a place in performance training, but it's not relevant to most people.

With respect to resistance training, HR has no relationship with work done. You can't infer anything from those reasons other than still pumping blood around your system.

If you want to guestimate a calorie count for resistance training, there is a cardio entry for it.

sijomial

kpsyche wrote: »

<SNIP> Based on this I seem to do more "work" during weight training then I do when I lift weights than when I'm hiking! Does this seem right? And related to that, should I be logging my weight training as cardio?

The real "work" done during weight training is the amount of weight lifted.
HR isn't a useful or meaningful metric during weight/strength training.

You can get an approximation of your weights calorie burn by logging the duration like this (in the CV part of your exercise diary)...

kpsyche

Thanks for the excellent and informative replies everyone.

I think I'll manually enter using the 'Strength training' CV as suggested (the calories calculated that way seem a bit more reasonable than what fitbit suggests I burnt... it reckoned 291cals for 36 minutes hehe)