It is a common belief that if you don’t leave a workout dripping in sweat, it didn’t count. Count for what? That is the main question. If you
didn’t sweat until your clothes need to be wrung out, does that mean it was a waste of time?  Before we talk about the physiology of sweating, let’s explore the why of exercise and what it “counts” for.

What is the goal for each workout? Do you know what you want to get out of your workouts?

There are a variety of reasons why people choose to exercise, and not all of them include sweating!

Some common exercise goals are:

• Improve health
  • Lower resting heart rate
  • Lower blood pressure
  • Lower Cholesterol
  • Boost immunity
• Lower risk of chronic diseases such as heart disease and diabetes
• Lose weight
• Stress reduction
• Improve mental health
• Increase bone density
• Gain strength
• Increase lean muscle mass
• Compete in a fitness or athletic competition
• Increase flexibility
• Improved sports performance
• Social connection
• Sweat it out!

Moderate exercise is very effective at improving health markers and reducing risk of chronic diseases.

Walking, for instance, may or may not cause you to break out in a sweat, but it is a very important way to increase bone density, boost immunity, create social connections, reduce stress, boost mood, and extend your life. That counts for a lot! Those are some pretty key quality of life measures.

Not everyone enjoys sweating. Shocking, I know! So, if you belong to the sweat free crew, keep it up! You are making significant impacts to your health.

Why do we sweat?

Heat is a product of metabolism. At rest, heat production is small. During intense exercise, heat production is large. The body is only 20-30% efficient which means 70-80% of the energy expended during exercise appears as heat. As body temperature rises during exercise, heat loss mechanisms cool the body. Evaporation, or sweating, is one of these important cooling mechanisms.

Evaporative cooling during exercise occurs when body temperature rises above normal. The nervous system stimulates the sweat glands to secrete sweat onto the surface of the skin. As sweat evaporates, heat is lost to the environment and the body temperature cools.

Evaporation of sweat depends on three things: 1) the ambient temperature and relative humidity, 2) the convective currents around the body (think wind or fans), and 3) the amount of skin surface exposed to the environment. High relative humidity reduces the rate of evaporation thus, more sweat stays on the surface of the skin rather than evaporating into the air. You are usually drenched in sweat in high humidity. The body struggles to cool itself because the heat is not being transferred from the body to the air which stimulates further sweat loss. This is basically useless sweat loss because it is not cooling the skin. In situations like an indoor cycle class, for instance, where the humidity is high and possibly the fans are turned off, sweat rate can be very high. This does not necessarily indicate that one worked harder. It is an indication of the decreased evaporation of sweat and decreased effectiveness of cooling the body.

Let’s look at some other factors that affect sweat rates. Heat-accustomed individuals have an earlier onset of sweating and a higher sweat rate during exercise. Individuals with a larger body mass have higher sweat rates compared to smaller individuals. As more of the body is covered by clothing or football pads, for instance, less evaporation occurs increasing sweat rate. Lastly, individuals with a higher fitness level have an earlier onset of sweating and a higher sweat rate during exercise.

As you can see, the amount you sweat is not a great indicator of how hard you worked. The more important factors to look at are the level of effort, your power output if it can be measured, your heart rate, or your calorie output. These are much better indicators of how hard you worked.

Sweat is simply a mechanism to cool the body. Yes, as intensity of exercise increases, more heat is produced and more heat needs to be lost. However, in a cooler environment or with a fan at your face, more sweat can evaporate or convective currents transfer heat and you will find you sweat less. That doesn’t mean you weren’t going beast mode all the way!

The next time you want to know if a workout “counts,” evaluate how well the workout met your specific goals. Did you take the actions required to hit your goals? If the answer is yes, then IT COUNTS whether you sweat or not!

Heather Flebbe, M.S.