Faster HR with heat suit on means more calories burned?

Former Member over 6 years ago

Hi Guys,

I have fenix 5s with the garmin HR run strap.

If I wear a heat suit on the stairmaster on a given speed, as an example, my heart rate might stay between 115 and 120

If I don't wear a heat suit and complete the exact same workout, my heart rate might only stay at 100 to 105

So my question is: am I correct that it makes sense for the calorie burn to be higher in the heat suit because it's more intense, even though the two workouts mentioned above as the same "distance" and "speed" settings?

Thanks for the help

0 mcbadger over 6 years ago

I would say not. Your core temperature is a very strong determinant of heart rate (the US DoD published some interesting stuff on this a few years ago). The more heat your muscles generate, the higher your core temperature will be, but how easily you can shed heat is important too, and in your case I would say the heat suit is keeping your core temperature higher than it would be otherwise, and your heart is working harder to try to cool it. The work done should be exactly the same, unless your suit is spectacularly stiff and takes work to bend the joints.

0 Former Member over 6 years ago

Thanks for the reply, mcbadger . I am not sure I can completely agree with this though. Garmin bases calorie burn completely on HR -- should they not? Maybe they are wrong but it just seems weird to put so much emphasis on HR if it essentially means nothing like you are saying.

Take a look at my heat suit stair climb today in which I had the heat on full blast in my apt:

https://connect.garmin.com/modern/activity/3492407911

My avg HR for this climb was 137 and my max is 155. Going at a VERY slow speed my HR was staying around 152, whereas the same speed without heat would be HRZone Zero (effortless) for me.

This was beyond intense workout and I drank 4.5 liters of water with pink salt and potassium chloride.

I am not saying you are wrong but I am just confused here... without the heat suit, I would barely have burned 400 calories in this workout... I'd be in Zone 0 the entire time.

I don't understand how the "work" can be the same when I literally felt like I was going to die from the intensity in the workout with heat suit on vs one without heat suit which is a total effortless walk in the park for.

Again, not saying you are wrong but the info you presented is very confusing to me.

0 JSRUNNER_ over 6 years ago

Darkice2 - you should burn more calories in high temperatures as your body is working harder in many ways to keep cool. There are also studies that show fat burning is increased excercising in hot conditions. However studies also show that maintaing excercise intensity in hot conditions is more difficult too.

However I also would ask why are you excercising in the heat suit and would certainly urge caution and build up slowly the intensity of excercise.

0 mcbadger over 6 years ago

it just seems weird to put so much emphasis on HR if it essentially means nothing like you are saying.

I didn't say it means nothing. I said "Your core temperature is a very strong determinant of heart rate" and "The more heat your muscles generate, the higher your core temperature will be".

All else being equal, there'll be a strong relationship between how hard you are working in terms of calories burned (which drives your core temperature up) and your heart rate, but that relationship depends on your weight and your fitness levels (including how efficient your vascular system is at carrying heat from your core to your surface to lose it).

These things are taken into account in the calorie burn models.

Me today climbing Skiddaw at the speed I would have done it 10 years ago would have a lower heart rate than then, partly because I'm lighter but also because I'm much better conditioned than I was then. The calorie difference would be about 15% less, because that's the fraction of my body weight I've lost since then, but heart rate alone would imply a bigger difference. Condition is something else Firstbeat tries to work out from your workouts, using good quality heart rate variability data from running, among other things, and this is what your watch is telling you about via the VO2max value.

JS, how many extra calories are burned in high temperatures? The extra work your heart is doing pumping is quite small compared with the work the OP's leg muscles will be doing on the stepper.

0 JSRUNNER_ over 6 years ago

mcbadger there is much evidence to show that excercising in moderate to warm temperatures increases calorie burn - though less on excercise in extremely hot temperatures.

https://www.acefitness.org/education-and-resources/lifestyle/blog/1061/do-i-burn-more-calories-when-it-is-hot-outside-or-cold

The extra calorie burn comes from a variety of places and is not just restricted to the extra pumping of the heart muscle.

0 mcalista over 6 years ago

OK, I'll start my answer with a quick lesson in thermoregulation. A large part of the way the body maintains a stable core temperature is by controlling blood flow. When it is cold, the body restricts blood flow to the torso and head, to reduce heat losses and maintain vital organs at a stable temperature. When it is hot, the body sends more blood to the limbs, and closer to the surface of the skin, so that heat can escape (especially when combined with the cooling effect of the evaporation of sweat).

The most accurate way to measure calorie burn is to measure the body's conversion of oxygen to carbon dioxide. While this can be measured directly in a sports science lab (with a mask and expensive equipment), it is very hard to measure gas exchange away from a lab. But in NORMAL CONDITIONS, heart rate increases with oxygen consumption in a predictable way, and so HR can be used to predict oxygen consumption and calorie burn. And HR is MUCH easier to measure, so most consumer electronics just go with that.

But in very hot conditions, the heart is working hard to circulate blood to small capilliaries close to the skin, and HR increases. Basically the heart starts working as a heat pump, as well as just an oxygen pump, and the predictable relationship between HR and oxygen consumption breaks down. HR is no longer a good predictor of oxygen consumption and calorie burn. So while your Garmin may be measuring HR accurately, in these conditions, it is not estimating calorie consumption accurately.

Now, the heart is a muscle, and if it is beating faster, it means the heart itself is burning more calories. But the heart itself is a relatively small muscle (when compared with your quads and glutes which are propelling you up the stairmaster), and the calorie increase is pretty small. If you want to truly maximize calorie burn (and not just see flattering numbers on your sports watch), take OFF the sweat suit and throw it away. Instead, let your body cool itself naturally, and go faster or longer on the stairmaster.

Also, the sweat suit is ineffective in terms of weight loss. While a jockey or fighter might use one to meet a weigh-in target, all they are losing is water weight, which will go straight back on as soon as they rehydrate.

0 Former Member over 6 years ago

First of all I'd like to say THANK YOU for these extremely enlightening and useful posts, guys!

mcalista, the reason I was using the vest was purely because it was getting my HR up so much easier and faster and I ideally want to be able to burn as many calories as possible in a short as possible amount of time. But obviously now I have learned it may be pointless and more dangerous than I thought

The annoying thing for me is going even at very high pace on the stairmaster I burn like zero calories. If I push myself to the MAX 450 per hour most, which is awful in my opinion. The heatsuit I was seeing numbers like 650 per hour.

I am not sure why I suck so much at burning calories but guessing because either

1) I'm 6% body fat and like 133lbs and 34 years old. 5 foot 8
2) maybe the garmin is just wrong even with HR strap and I'm burning more? idk
3) my MAX hr is only 155 and my resting can be as long as 35. My conditioning is already good. I regularly was doing 5 to 6 hour stairmaster sessions before per day. I am a stair and abs addict.

Do I really suck at burning calories and if so what is main reason? It's definitely not that I don't go "hard" enough, I know I do push myself to the max. I'm thinking it's just because I'm already super lean?

Also I find this embarrassing... I burn 20 to 30 Active calories walking a mile!!!!! can this seriously be accurate? Is walking really that little effort for me? would love to get feedback here because I find this so damn frustrating that I basically burn zero calories.

How can my BMR be as high as 1850 on my Garmin yet if I walk an entire mile I burn basically nothing?

And if you guys are wondering I do have severe OCD about calorie burning (medically diagnosed OCD). It's very hard for me because I just expect to have a 100% accurate way to get the calories right. I've been thinking of doing lab testing just to get an idea how accurate my fenix 5 with HR strap actually is. If anyone has recommendations for such a place in NY/ east coast area please let me know.

Also, lets keep this discussion going... CRYOTHERAPY. I do it for tennis muscle recovery. The claim is burns 500 to 800 calories in 3 minutes at -256 degrees since body goes through extreme measures to warn up. Do you believe it or just marketing? I regularly do 6 minutes of cryo at least 3 days per week and it would be great to know FOR SURE how many calories it actually burns, because it kinda impacts how I would eat that day lol. But regardless of the calories I would highly recommend trying this out, it's magic for recovering soar body

Again really appreciate the great feedback mcalista JSRUNNER_ mcbadger !!!

Best Regards

0 JSRUNNER_ over 6 years ago

Darkice2 you are obviously very fit and very lean with quite a large muscle mass. With alot of muscle then you would expect to burn more calories just by existing :) and you should also have improved efficiency when you are excercising so you'll burn less calories for the same result. As for accuracy - although these consumer devices are vastly better than they were a few years ago they are still very approximate when it comes to some metrics such as calorie burn - a lab test is the way to go but again that won't necessarily help you in your day to day training - it will show you how closely garmin matches the lab test for the activity performed.

I'm not familiar with cryotherapy techniques but the claims do seem extreme - I would have thought there should be some independent research available if you look around.

A brief scan seems to show that the 800c burn is an extrapolation of data and not supported by independent research. There's little or no evidence to show that the treatment is better than ice-bath or cold water swimming.

Even the muscle recovery effects are disputed - despite ice-baths and cryotherapy being used by many top athletes. But there is a long history of sport adopting equipment or techniques without sufficient supporting independent research (just look at the history of running shoes :) )

0 Former Member over 6 years ago

Hi All,
JSRUNNER_ ,
mcalista ,
mcbadger

Any ideas how I can increase my calorie burn on stairmaster ? The heatsuit is obviously a bad option, and due to increased fitness levels even if I go super hard without my heatsuit its very hard for me to even get my HR above 125....

The only other thing I can think of is something like wearing a weighted vest and adding that "weight" to my Fenix 5 settings some how.

I want to be able to scorch huge amounts of calories without going at a super high pace. I'd rather go slower and longer with increased resistance or something similar.

Thanks for any ideas!

0 BeneGi over 6 years ago

In your example, the calorie burn with heat suit on hast to be higher. You don't need any higher sports science to know why:
First: You have to accelerate and move the heat suits weight.
Second: Your heart is a muscle. If it beats faster, it burns more energy.

I don't want to say it is a significant difference, but it is a difference.

If you want to increase the burn significantly, raise the resistance with the same speed or you a weighted vest like suggested.