During exercise, your sweat rate increases noticeably. However, how much you sweat may differ from your exercising partner, even when you are completing the same workout session. The amount of sweating you experience may depend on your gender and family history. Other factors, such as exercise intensity and the weather, can also affect your sweat rate and volume.
Science of Sweating
Your body depends on sweat to help you fend off heat. When you exercise, as your body produces heat, your core temperature may increase slightly. Your brain then signals your sweat glands to start releasing sweat. When your sweat is evaporated, or turned into water vapor in the air, it creates a cooling effect on your body. Your sweat is created from plasma, the fluid portion of your blood and contains electrolytes such as sodium and chloride.
In hot weather, your sweat rate may increase faster and greater than normal. Sweating is your body's most significant line of defense against overheating. In order for this method to have a cooling effect, the sweat must be able to evaporate into the air. During humid weather, this becomes a challenge. You may feel that you are sweating more than usual because the fluid is not getting removed from your skin as it would in dry air. If exercising indoors, use a fan to create air circulation which will promote evaporation.
It appears that men may have a greater sweat rate than most women. While women actually have more sweat glands per area than men, their glands do not secrete the same amount of sweat. However, this does not appear to significantly alter their ability to deal with heat.
Your heredity may play a role in how much you sweat, as well as how much sodium you lose through sweating. If you come from a family of people who sweat heavily during exercise, as well as at rest, genetics may play a role in your sweat rate.
Trained endurance participants, as well as those who adjust, or acclimate themselves, to exercising in hot weather, tend to increase their sweat rate. While your sweating may seem to increase as you become more conditioned, you will start losing less sodium through your sweat.
It is important to drink fluids to replace any liquid lost through sweating. If you sweat heavily, you may also need to ingest some salt to make up for electrolyte losses. Sometimes it may be helpful to weigh yourself before and after a heavy or long exercise session. You should avoid losing more than 2 percent of your pre-exercise weight to prevent dehydration.
- American Council on Exercise; Electrolytes: Understanding Replacement Options; Shawn Dolan; August 2010
- "NSCA's Performance Training Journal"; Measuring Hydration Status in Athletes; Debra Wein, Caitlin Reilly; October 2010
- "Physiology of Sport and Exericse: Fourth Edition"; Jack Wilmore, David Costill, M. Kenny; 2008