In order to lose weight, you have to burn more calories than you are consuming, so we are often interested in what sorts of situations help us burn the highest number of calories.
So, do you burn more calories being hot or cold? In other words, do you burn more calories in the heat, or do you burn more calories in the cold? Does sweating burn calories? Do hot flashes burn calories? Does being hot burn calories?
Does being cold burn calories? Does shivering burn calories?
In this guide, we will discuss how temperature may affect the number of calories you burn and look to answer the question: “Do you burn more calories being hot or cold?”
We will look at:
- Do You Burn More Calories Being Hot Or Cold?
- Do You Burn More Calories in the Heat?
- Does Being Cold Burn Calories?
Let’s get started!
Do You Burn More Calories Being Hot Or Cold?
Before we attempt to answer the common question: “Do you burn more calories being hot or cold?”, it’s important to establish that the number of calories you burn in a minute will depend on your body size, body composition, genetics, what you are doing, etc.
However, the temperature can influence how many calories you are burning, such that you may burn more calories in the heat and more calories when you are cold than when your body is at a comfortable temperature.
It’s important to note that body temperature is regulated primarily by the hypothalamus, which acts to try and maintain temperature homeostasis by triggering various thermoregulatory mechanisms like shivering, sweating, vasoconstriction, and vasodilation to help restore normal body temperature after perturbation.
These different temperature-regulating mechanisms can affect your metabolic rate based on the increased energy demand to employ the mechanism over your resting conditions.
This is why your body can potentially burn more calories in the heat and when you are cold.
Let’s look more specifically at the two temperature extremes:
Do you burn more calories when you are cold? Do you burn more calories when you are hot?
Do You Burn More Calories in the Heat?
Let’s first address: does being hot burn calories?
In general, yes. You burn more calories in the heat, and you burn calories when you are hot than when your body is at a homeostatic temperature.
However, this increase in the number of calories you burn in the heat is not very significant.
So, why do you burn more calories being hot?
The two primary thermoregulatory regulatory mechanisms that kick in when your core temperature rises are sweating and increased blood flow to the skin.
Sweating helps dissipate excess body heat because as sweat droplets accumulate on the surface of your skin, heat energy from your body is used to turn the liquid sweat droplets into water vapor.
Essentially, the heat causes a phase change; this process is known as evaporative cooling.
For your sweat glands to produce and excrete sweat, energy is required, so a few more calories are burned sweating than at rest.
Therefore, technically, the answer to the question: “Does sweating burn calories?“ is yes, but this is such a small number of calories and a much less significant contributor to the bump in energy expenditure in the heat than the increased workload of the heart muscle.
In terms of the heart, another thermoregulatory mechanism to help cool your body when you are in the heat is to increase cutaneous blood flow, which refers to the amount of blood circulating to your skin.
This requires your heart to beat faster and harder (increasing cardiac output) to circulate more blood to the skin. Because your cardiovascular system has to work harder—and the heart is a muscle—you burn more calories being hot.
This is all exacerbated if you become dehydrated because your plasma volume will drop, which means that you have a lower volume of blood, and your stroke volume, or the amount of blood your heart can pump per beat, decreases.
This requires your heart to beat faster to maintain the necessary cardiac output.
Do hot flashes burn calories?
While women going through menopause would probably love to hear that the dreaded hot flashes at least have the benefit of burning calories, this, unfortunately, isn’t likely the reality.
Does Being Cold Burn Calories?
Now, let’s address the other heat vs cold calories question:
Do you burn more calories in the cold?
Here, the answer is: it depends.
Just being in a cold environment will not inherently increase the number of calories you are burning.
But, specifically, does shivering burn calories?
However, you will burn more calories in the cold if you are cold enough to start shivering, particularly if your core temperature starts to drop and you become at risk of hypothermia.
According to research, when your body temperature drops too much, and you’re in danger of hypothermia, the hypothalamus can increase your body’s overall metabolic rate to generate more heat and counteract hypothermia.
When your metabolic rate increases, you burn more calories, and shivering helps you warm up by generating body heat.
Note that hypothermia is defined as a drop in core body temperature below 35 degrees Celsius or 95 degrees Fahrenheit.
According to the National Institutes of Health, shivering is an energy-demanding process, so you will burn more calories shivering in the cold than you would at rest, or you would just being in the cold.
Shivering is a natural thermoregulatory response by the body to help increase body heat.
Essentially, shivering is an autonomic nervous system response, which means that it causes involuntary muscle contractions.
In the case of shivering, these contractions are very rapid and small.
By contracting the muscles, your body produces heat, which will help raise your core temperature when you are too cold.
Although on a much smaller scale and involuntary instead of voluntary, just as exercise burns calories because you are contracting and using your muscles, shivering burns calories because your muscles are contracting.
These contractions require ATP (energy for cells), so you must metabolize glucose or glycogen to generate ATP.
Shivering also increases the production of a hormone known as irisin, which can activate brown fat.
This, in turn, is thought to increase your metabolic rate and fat burning. Interestingly, this same hormone is produced by exercise.
According to one study that looked at the metabolic and physiological effects of shivering by placing subjects under cold blankets, shivering was found to increase muscle contraction activity by 88%, while those who were just cold but not shivering increased muscle activity by 13% over baseline.
This means that perhaps you do burn more calories being cold even if you are not shivering, but the real increase in calorie burn from being cold comes when you are shivering.
So, how many calories does shivering burn?
The number of calories you burn per minute shivering will depend on your body size and composition.
That said, the study above found that subjects who were shivering demonstrated a 48% increase in energy expenditure per minute, which means that they were burning almost 1.5 times as many calories being cold and shivering vs. comfortable at rest.
However, other sources report that shivering can burn a significantly higher number of calories and may increase your basal metabolic rate by as much as 5 to 6 times.
The number of calories burned shivering is thought to be dependent upon the intensity of the shivering, which in turn, is based on the core temperature and a person’s body fat percentage; people with more brown fat tend to shiver less vigorously.
Note that prolonged exposure to the cold increases the risk of hypothermia, according to the CDC, and hypothermia can be fatal if severe or not reversed quickly enough.
Therefore, just because you may burn more calories being cold and shivering like a trembling leaf should not be motivation to subject yourself to extremely low temperatures to expend a few extra calories for weight loss.
Finally, it’s also important to note that exercising in the cold will likely negate most of the potential increase in energy expenditure being cold.
When you exercise, your core body temperature increases, which will help stave off the shivering mechanism.
Remember that although you might shiver briefly at the beginning of a winter outdoor workout, once you get in a good warm-up, as long as you are wearing proper clothes for the environmental conditions, you should stop shivering.
For a guide on running in the cold, click here.