Medication, HR and calories burned.

crafty30

I've recently been diagnosed with a heart arrhythmia and have been put on beta blockers. I've been cleared to exercise but the medication has slowed my heart rate right down so that when I exercise, it doesn't get up anywhere near what it used to, so the calories burned on my HR monitor is much lower than before. This is probably a stupid question but does this mean I need to work out harder, longer to get the same burn as before? Or is it a false reading really as the medication is controlling my HR. Sorry if this sounds stupid!

ccjlgrider

I am on beta blockers too. I take them for migraines. You can't use a HRM while on beta blockers. It won't be accurate as you've discovered. You have to go by how you feel when you work out. I use a fitbit to help guide me because it goes off your steps. Nowhere near as accurate as a HRM. But for us, HRM are useless.

crafty30

Thanks for your reply! So I'm not burning less calories than before then? I thought your HR had to be in a certain range to be effective.. mine pretty much stayed around 100 the whole time so my calorie burn looked pathetic!

LKArgh

You burn calories by moving, not by getting your heart rate up. If you are putting the same effort in whatever you are doing, then there is no reason to doubt you are burning calories same as you used to.

brianpperkins

The HRM was never truly accurate for calorie computation to begin with. For certain activities HR (more a percentage of heart rate reserve) can serve as a proxy for effort which it then uses to estimate calories burned. More often than not, the resulting number is wrong ... beta blockers or not.

crafty30

Thanks for the replies. . Ok, great. . I'll just carry on doing what I was doing before and ignore the numbers..it certainly feels like I'm working hard so I'll just go by that!

Azdak

crafty30 wrote: »

Thanks for your reply! So I'm not burning less calories than before then? I thought your HR had to be in a certain range to be effective.. mine pretty much stayed around 100 the whole time so my calorie burn looked pathetic!

The "HR Range" refers to your % of maximum heart rate, not the actual HR number itself. For exercise, a beta blocker just "recalibrates" your heart rate scale. Your heart rate at 80% effort will be lower, but it's still an 80% effort. Calories burned is based on absolute workload (e. g. Running speed) and body weight, so if your are doing the same workload, calorie burn will be the mostly the same also. The HRM number is messed up because the HRM doesn't know your max HR is now so much lower.

crafty30

Azdak wrote: »

crafty30 wrote: »

Thanks for your reply! So I'm not burning less calories than before then? I thought your HR had to be in a certain range to be effective.. mine pretty much stayed around 100 the whole time so my calorie burn looked pathetic!

The "HR Range" refers to your % of maximum heart rate, not the actual HR number itself. For exercise, a beta blocker just "recalibrates" your heart rate scale. Your heart rate at 80% effort will be lower, but it's still an 80% effort. Calories burned is based on absolute workload (e. g. Running speed) and body weight, so if your are doing the same workload, calorie burn will be the mostly the same also. The HRM number is messed up because the HRM doesn't know your max HR is now so much lower.

Thank you, that makes sense!