When exercising perspiration causes the loss of water from the body along with electrolytes or salts and results in dehydration, this is an ongoing process within the human body where the fluids need to be replaced for optimum bodily functions.
Proper rehydration requires not just water but salts as the body needs these for efficient muscle contractions and nerve impulses. The main electrolytes are sodium, potassium, calcium, magnesium, chloride, hydrogen phosphate and hydrogen carbonate. Exercise depletes the bodies’ salt reserves more quickly bringing the onset of fatigue faster and in this instance water does not have a sufficient amount of these electrolytes to rehydrate as well.
There are three main types of sports drinks available to rehydrate before, during or after exercise with differing amounts of sugars for differing intensities as this is important for performing at your best. Isotonic drinks have the same concentrations of sugars and salts as the human body and are designed to rehydrate sports athletes that perform team sports, middle distance and long distance running, cycling and swimming.
Hypertonic sports drinks have a higher concentration of sugars (carbohydrates) designed to replenish glycogen stores in muscles for after high intensity training or very long distance events like marathons while hydrating and replacing essential salts within the body too.
Hypotonic sports drinks are designed for lower intensities as they have a lower concentration of sugars designed to rehydrate sports people like gymnasts and jockeys as they do not use up as much glycogen as runners or team sport athletes.
When working out at home or within the gym you have to consider the intensity you will be working at to accurately replenish sugars, salts and water within the body. A high intensity workout will require a hypertonic sports drink whereas a moderate or low intensity workout will require isotonic or hypotonic drink.
Daniel O Donnell (much loved by old ladies)
Personal Trainer