A lot of our Personal Training clients ask me why, whilst on just our warm up jog, I start to sweat, or ‘perspire’, before they do. A common myth is that people who sweat are not very fit- in fact it’s the opposite!
First, let’s take a look at why and how we sweat. A humans body temperature should be on average 37 degrees, whilst resting. If our temperature rises above this level, especially during exercise, the brains processing centre that controls our body temperature, called Hypothalamus, is triggered.
Messages from this Hypothalamus part of the brain tell tiny muscles to pull the hair on our skin down, so they lie flat. This causes more heat to escape our bodies. (the same muscles make our hairs stand up when we’re cold to trap heat). Glands in the skin (we have around 2 million of them in total), then secrete sweat onto our skin, which increases heat lost through evaporation. More blood is also ‘shunted’ to the skin’s surface, so more heat can evaporate quicker.
So why do fit people sweat more? Because sweating more during exercise means your body is more efficient at dealing with the increased temperature. The body will shunt more blood to the skin’s surface more quickly and release heat from the body. The sweat glands also have increased output compared to an unfit individual, and so more sweat is produced. Unfortunately it’s not just about fitness levels. Overweight and obese people will also sweat a lot more as the excess fat acts as and insulator and so therefore body temperature rises a lot faster.
While fit people and of course Personal Trainers produce more sweat they lose less sodium than sedentary people, because more of it is reabsorbed by the body. Men also sweat a lot more than women. This is because although women have more sweat glands than men. The men secrete more sweat in each gland.
So the next time your in your 30th Fitness Class, or 20th Personal Training sessions, and your sweating MORE than you used to, don’t worry! Just smile to yourself, knowing that now your body is even better at cooling you down!