MSU Extension Food & Health

It is important to stay hydrated and avoid excessive heat during the hot summer months because we lose a lot of body fluid through sweat. But does this mean you should avoid sweating at all costs? Not at all.

People sweat for many reasons such as hot weather, nervousness, a fever, exercise, and being in a sauna. Sweating can dehydrate us, stress us out, or remind us our body is fighting an illness. In contrast, it may invigorate us on a hike or when working out in a gym. Besides, isn’t sweating what you are supposed to do in a sauna anyhow?   

Why do we sweat?

Perspiration (or sweating) is the major way our body regulates its temperature. Water is released through glands in the skin, evaporates off the skin and the body is cooled. During exercise, muscles heat up more, so more sweat is needed. Cooling is the major function of sweating. Without it, our body could not release excess heat and we would die. This is true regardless of whether we are sick in bed or relaxing in a sauna.

What is in sweat?

• Mostly water
• Small amounts of sodium, potassium, calcium and magnesium – electrolytes that help trigger various electrical responses in the body (e.g., flexing muscles). This is the reason why drinking electrolytes during and after high impact or long periods of exercise is beneficial.

• Small amounts of pheromones, which have little significance in humans compared to other animals, but have shown interesting function in limited research studies.

• Bacteria, which grow in the released sweat and make it stink. Antiperspirants, certain shirt fabrics, and frequent bathing can remedy this.

• Small amounts of released toxins. The belief that sweat removes significant levels of toxins from the body is often exaggerated because most of sweat is made up of water. There is minor removal of heavy metals and BPA plastics but the liver and kidneys do most of the body’s detoxification. In fact, a person’s overall nutrition likely has a greater impact on body detoxification than sweating because good nutrition supports healthy organ function.

Is sweat a good thing? 

From a physiological perspective, sweating is absolutely a good thing. Our body would overheat if we did not sweat. But some of the activities that cause sweating (excessive time in the heat, being nervous or sick) is associated with other problems, such as heat exhaustion, anxiety and illness. In contrast, activities such as exercise and controlled time in a sauna are healthy. This would suggest that it is not the sweating itself, but the activity behind it, which defines whether sweating is healthy or not.

Sweating during exercise usually means you are reaching a level of exercise that promotes cardiovascular health.  Some evidence suggests sweatier people are getting a more intense workout, and more fit individuals sweat sooner and more profusely, but tremendous variation in the timing and amount of sweat across individuals makes those claims unreliable.  Instead, focus on reaching a level of exercise (or sauna time) in which sweat actually shows up, rather than measuring the timing or amount. Just because it is summer and hot outside, do not assume it means you should not work out. On those days, exercise in air-conditioned environments, choose the cooler times of the day, and keep hydrated. Stop exercising if you experience unusual symptoms, such as dizziness and nausea.

As for saunas, research is confirming some of the long-standing beliefs of Finnish people that sweating in saunas is beneficial to health. Heat-induced stress relief and possible positive effects on heart health may be the actual benefits. Similar to exercise, the activity behind the sweating (not the sweating itself) is what is actually making us healthy.

How to counteract fluid loss when sweating:

1. Drink water throughout the day – not just when you think you need it.
2. Avoid caffeinated and alcoholic drinks, which can amplify the effects of dehydration.
3. Choose water over sugary drinks, and be careful not to drink too much fruit juice. Instead, add flavor to water with flowers and fruit infusions that use less sugar.
4. During intense exercise and heavy sweating, replace lost electrolytes with drinks or foods that contain them. For example chicken, fish, milk, yogurt, greens, sweet potatoes, avocados, mangoes, pomegranates and bananas each have over 300 mg of potassium per serving.

Do you want to learn more?

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