Does a lower heart rate = slower weight loss?

jenconv

I’m a 42 year old female, 5’3 and currently 224lb down from 247lbs at the beginning of June. I have been working out with a trainer twice a week (strength and cardio), with at least one other gym session a week and I’m keeping cals to 1500ish. So far so good-I’m loving the exercise and the results have been amazing.

I’ve had health problems for years and recently I was prescribed a beta blocker propranolol to try and help prevent debilitating migraines. In the 2 PT sessions since then I’ve struggled to get my heart rate above 120 when in the past I’ve had it between 160-170 during the cardio parts of my sessions.

Does the lower heart rate mean that I’m burning less calories even though the intensity of the sessions hasn’t changed? I wear a Fitbit and the daily calorie burn has dropped too - it was previously around 3000 on an exercise day and 2400 on a non exercise day.

I still have at least 85lbs to go before I’m a healthy weight and I’m getting disheartened thinking that this is going to take a lot longer than I’d hoped it would.

psychod787

No, HR is just a sign of fitness. The "fat burning zone" is a myth. The more weight you lose, the less hard the heart has to work. It can also be a compensation to weight loss in general, but that's speculatory from my reading. JMHO's here.

seska422

My Fitbit reported an inflated calorie burn before I started taking a beta blocker. Now my reported calorie burn lines up quite well with my actual weight loss rate.

Pulse rate is a proxy for determining intensity. Your medication is artificially reducing your pulse but the same exercise intensity will burn the same calories. Keep in mind, though, that smaller bodies take fewer calories to lug around so you'll need to work out more for the same calorie burn as you lose weight.

wannabeskinnycat

I'm 42, 5'3 and 249lb - down 35lb since April. I'm eating at a deficit so I lose weight and other than being curious about my heart rate info, I didn't really know what I was looking at. I don't have high blood pressure, amazingly - and my GP says other than having that checked, I should notice my Resting Heart Rate. Fitbit data tells me it was 85bpm in April and now it's 67bpm so my heart is not having to work so hard to function normally as it did 5 months ago. For me, improving my heart health far outweighs the amount of calories I burn each day. I don't do regular exercising as I'm mainly rolling about in my electric wheelchair but me getting my heart pumping for half an hour a day is really paying off. And calorie counting for the deficit is losing the fat

I feel I've peaked for the most amount lost in a month and I'm just gonna have to some patience. Slow & steady wins the race as they say. It took me a decade to get morbidly obese so it's gonna take a while to get off. My weight trend app tells me it'll be sometime in 2022 so it's nice to have some sort of idea - do you use one?

sijomial

Heart rate doesn't equal calories which is a major problem with using HRMs to get estimates.
(e.g. my heart is 20% more efficient due to improved CV fitness - it's a better trained pump now.)

But if the beta blocker is preventing you from exercising as intensely then yes your exercise burns will be lower - but it's the intensity drop that is the difference. But for day to day activity it should have little impact on your calories expended unless the calming effect means you move less.

For cardio your achievable maximal effort will definitely have reduced.
If strength training your HR is an awful way to estimate anyway with or without medication.

I was on propanolol for migraines too but couldn't tolerate the feeling of hitting an artifical cap on my HR when pushing hard during games of squash - my HR obsinately refused to go high enough to meet my performance needs. Ultimately addressing the cause of stress and an alternative drug as a prophylactic treatment was more effective without the side effects.

kshama2001

I feel like my appetite went up and am sure my stamina went down after starting the beta blocker Metoprolol.

My doctor had speculated that my increased heart palpitations might have been due from my anemia getting out of control. Since it's been back under control for some time, I tapered off of the Metoprolol. I don't recall exactly when and get a 90 day supply, so it's hard to pin point. The excessive amount of palpitations did not return.

I'll be restarting the activity for which I had decreased stamina again shortly and am curious to see how it goes.

mmapags

OP, I'm guessing your previous burns were inflated based on heart rate and your current ones may be a little under inflated. This is an inherent problem with using heart rate as a proxy for calorie burns. It's probably better to use MFP estimates for now and keep accurate track of calories and burn data for 6 to 8 weeks. At that point, you should be able to determine accurate burns based on your own data.

I can't see any reason your weight loss would slow at the calorie level you are eating. Generally, burning more calories from exercise allows us to eat a little more while maintaining our deficit. Have you been eating back some portion of your exercise calories?

Your rate of loss looks like its about 2 lbs per week, which is aggressive but not unreasonable for someone who has as much to lose as you did to start. As you get closer to goal, you'll want to slow down that rate of loss as the body can only metabolize a certain % of stored fat before cannibalizing lean mass.

There is a chart that shows recommendation for this but I don't have it. Possibly someone will post it. But, yes, at some point your rate of loss will and should slow. But not because of the inaccurate relationship with your HR and calorie burn. Calorie burns are based on work done (METS) and if that hasn't changed, your burns haven't changed.

A cautionary word about becoming too dependent on calorie burns from exercise. Exercise is for fitness and calorie control is for weight loss from a macro point of view. Both fitness and a healthy body weight are essential components of health.

lgfrie

I can't speak to the theory side of it because HR is something I just don't know much about relative to the above posters, but empirically speaking:

• my resting HR has come waaaaaay down since I started dieting - from around 84 to 68 on average
• my exercise HR for the same level of intensity on my cardio machine has plummeted from 132 to 116
  
  During that time, my rate of weight loss has not slowed one iota beyond the incremental reduction in TDEE that MFP's goal tool and my TDEE calculator both predicted would happen.
  
  So I'm not sure what the correlation is between HR and fat burn, but less direct than some people think, is my thinking.

jenconv

Thanks to everyone that took the time to reply-I feel much better after reading through them.

I’m going to keep on giving it my all in my gym sessions and keep my nutrition on point and hopefully a year or so from now I’ll be celebrating not only being at my goal weight but also being a stronger and fitter version of myself.

Azdak

The decrease in HR per se does not mean a decrease in calories burned.

A beta blocker-esp at first- can result in a modest (eg 5%) decrease in Vo2max. So you may not be able to work out as hard or as long as before, which can mean a small reduction in TDEE.

However, you still can achieve a training effect, so it is possible to get back to that fitness level and calorie burn. I have come across anecdotal evidence of people seeing some weight gain after starting a beta blocker, but that should be transient.

Plenty of people on beta blockers successfully lose weight.

heybales

Also, the trackers are attempting to NOT use HR-based calorie burn for the daily activity level of stuff.
They use step and resulting distance to get calorie burn for daily stuff.

Med's that push resting HR inflated are more an issue - devices things you might be in exercise zone and apply HR-based calorie burn at worst end of calculations.

kshama2001

mmapags wrote: »

OP, I'm guessing your previous burns were inflated based on heart rate and your current ones may be a little under inflated. This is an inherent problem with using heart rate as a proxy for calorie burns. It's probably better to use MFP estimates for now and keep accurate track of calories and burn data for 6 to 8 weeks. At that point, you should be able to determine accurate burns based on your own data.

I can't see any reason your weight loss would slow at the calorie level you are eating. Generally, burning more calories from exercise allows us to eat a little more while maintaining our deficit. Have you been eating back some portion of your exercise calories?

Your rate of loss looks like its about 2 lbs per week, which is aggressive but not unreasonable for someone who has as much to lose as you did to start. As you get closer to goal, you'll want to slow down that rate of loss as the body can only metabolize a certain % of stored fat before cannibalizing lean mass.

There is a chart that shows recommendation for this but I don't have it. Possibly someone will post it. But, yes, at some point your rate of loss will and should slow. But not because of the inaccurate relationship with your HR and calorie burn. Calorie burns are based on work done (METS) and if that hasn't changed, your burns haven't changed.

A cautionary word about becoming too dependent on calorie burns from exercise. Exercise is for fitness and calorie control is for weight loss from a macro point of view. Both fitness and a healthy body weight are essential components of health.

Here it is

mmapags

Thanks! Going to copy it for future use.

koalathebear

Not sure what else to use then given that MFP doesn't take into account my level of fitness, my heart rate etc to calculate calorie burn through exercise. The fat burning zone might be a myth, but I've found that my garmine seems pretty good at calculating calories and they seem to co-relate to my weight loss.

Danp

The only advice I can offer is don't go to internet strangers with cardiac questions. If you're genuinely concerned (or even just slightly concerned) go and see your doctor.

Never take anything to do with your heart for granted

Azdak

Danp wrote: »

The only advice I can offer is don't go to internet strangers with cardiac questions. If you're genuinely concerned (or even just slightly concerned) go and see your doctor.

Never take anything to do with your heart for granted

Appreciate the concern, but the OP is not asking a “cardiac question”, nor seeking medical advice.

The question is: does taking a medication that lowers heart rate decrease calorie burn during exercise and other activities.

It’s a straightforward, informational question that many people here are fully qualified to answer.

I have addressed this issue literally hundreds of times, both in these forums, and in the real world with clients. In 90%+ cases, the doctor who prescribed the beta blocker never told the patient about its HR blunting effect. They also have no knowledge of the relationship between heart rate and calories burned.

heybales

koalathebear wrote: »

Not sure what else to use then given that MFP doesn't take into account my level of fitness, my heart rate etc to calculate calorie burn through exercise. The fat burning zone might be a myth, but I've found that my garmine seems pretty good at calculating calories and they seem to co-relate to my weight loss.

Level of fitness or HR isn't really needed to improve calculation for calorie burn thru exercise - in fact many of the comments have been sharing how that change in fitness & HR can totally deceive such calculations.

Let's say you get past your 1st two weeks of just moving more from a really sedentary lifestyle, and your heart isn't beating out of your chest just to walk to the bathroom anymore. But still very high when doing a fast for you walk.

So you do a 2 mile walk in 40 min with avgHR at 150 - during that chunk of time say you'll burn 210 calories.
You have a HR monitor and app that estimates 593 calories though based on gender, age, and BMI (which is very high).

Now 6 months later of doing that every other day and then every day, but your weight has stayed the same. Fitness has improved, restingHR from 70 to 50.
Now the 2 miles takes 30 min with avgHR at 100 - during that chunk of time you'll burn 233 calories now.
But your HR monitor app sees the same BMI but lower HR and estimates 218 now.

You are moving the same amount of mass the same distance - you burned pretty much the same amount of calories.
You could just do it faster, and it wasn't as much of a workout for the cardio system as it once was.

So MFP or any other database using entries based on level of effort (pace) will be just fine.
HR-based calculations can be all over the place depending on many factors and what type of calc's they are using.

BTW - I used actual HR-based formula for those estimates above, and distance formula for those. Guess which is more accurate.