A recent study found that an hour-long hot bath burns “around 140 calories.” The study was tiny (14 men), but that, of course, didn’t keep it from being widely reported. According to one of the study’s authors, writing in Discovermagazine:
[The men]
The study also found that hot baths reduce the chronic effects of inflammatory diseases and reduces blood sugar spikes after eating.
I know better than to trust a single, very small study. And if a hot bath does burn a significant number of calories, that doesn’t mean it offers the same health benefits as exercise. What I’m trying to understand is how this would work (if it works), particularly:.
How do heat shock proteins cause the body to burn calories?
If I step from a 68 degrees building into a 115 degrees desert, would my body produce calorie-burning heat shock proteins?
There’s a link to the original study in the article.
When the body is heated in order to release the heat the body dilates the blood vessels in the skin in order to allow heat from the core to radiate to the environment. The increased volume of blood means the heart needs to pump faster. The shock proteins are produced by the body in reaction to stress but are not the cause of the calorie burning.
I’m tempted to call BS on this claim. As a thought experiment, suppose you were totally immersed in 40˚C water. Where the heck would the body dump the “burned” energy, while still maintaining a survivable body temperature?
According to the article, they were put in a 40˚C bath. So it wasn’t a thought experiment.
And their core temperature did rise over the course of an hour. It takes a while to heat up something as dense as a human body, and some heat would be lost thru respiration, and sweating of the head and face. Normal body temp IIRC is 37 degrees Celsius, so it wasn’t like they were being simmered.
PS - the headline of the article linked is pretty IMO misleading.
No, it doesn’t - a walk is going to actually condition you and exercise your legs and assist in peripheral circulation. Hot baths are just heat acclimation.
‘I don’t have to diet or exercise - just soak in a hot tub’. That is not how it works.
I recall something a bit opposite, an experiment where exercise (stationary cycle) included the hands and forearms being in a lower-pressure cooled environment. Apparently this allowed the body to dump generated heat faster. Consequently the exerciser felt more comfort, less fatigue, better endurance. The low pressure helped draw more blood flow to the hands which were cooled by a refrigerant pumped through gloves.
The question I guess is does the body react to overheating with some sort of body chemistry activity that burns a lot of calories? I have trouble imagining elevated heart rate makes very much of a difference, or aerobic exercise would be better for us than it is.
A quick search reveals any number of cites about humans burning more calories in warm conditions than cool ones. The stated cause is the need to try to dissipate heat, through moving extra blood to the skin, for example.
I’d trade all my powers, my money and my soul, and any number of cites for a clear answer to this question: Where in the Hll of the freaking G-d do all these calories go*?
It sounds like it does increase your metabolism but it also sounds dangerous. Your body constantly burns calories to produce heat, but you also shed this heat rapidly.
If it is true that your body’s metabolism increases when you are in hot water (literally), then all that extra body heat would have no where to go. If your body heat gets too hot then you could have a heatstroke. So that sounds like a risky way to lose weight.
Well, remember, it’s harder to get rid of heat than to create it. Heating up the body is easy-- you’re already getting lots of free heat as the waste from everything else the body is doing, and if you need more heat than that, it’s pretty much one for one, turning food calories into heat. Cooling the body is more difficult; you need to pump more blood, faster, and move lots of water out through the skin, etc. etc.
Which isn’t to say I endorse the conclusions of this study.