Hydration and exercise
Staying hydrated is important for everyone, but most people could get dehydrated without realizing, while exercising or engaging in a physical activity.
Our bodies require water to function on a daily basis. This is because water is key in regulating body temperature, transporting nutrients, removing waste material, digesting food and lubricating the joints.
It is also important for cellular reactions. Staying hydrated is important for everyone, but most people could get dehydrated without realizing, while exercising or engaging in a physical activity.
What causes you to sweat?
When you work out or engage in any physical activity, your body temperature increases. In order to remove this additional heat, the body secretes sweat, which eventually helps cool you down. Sweat consists of electrolytes (like sodium) and water, and hence, you lose a lot of water with perspiration.
What could lead to loss of water/fluids while engaging in a lot of exercise or physical activity?
Most of us know that sweating leads to water loss. But besides perspiration, physically active people lose water due to other reasons as well:
- Increased sweating and water loss via skin, as the body tries to regulate temperature
- Fluid loss during respiration, urination
- High fibre diets: These could lead to a slight increase in faecal water loss
- High protein diets: Digestion and excretion of metabolites because protein intake requires additional amount of water. Usually this amount is insignificant but it may become important if the athlete is consuming less fluid for training purposes
How does dehydration affect the body during physical activity?
While everyone knows that water is required for the proper functioning of the human body, not many know that being adequately hydrated significantly affects how the body functions during physical activity. Under severe dehydration, the following complications may be seen:
- Mental performance may be affected
Under certain conditions, dehydration can lead to impaired mental capabilities and negatively affect working memory, short-term memory, mood, visual motor skills and arithmetic capabilities.
- The ability to exercise and other physical functions may be affected
Dehydration could affect cardiac functioning, sweat production and the ability of the body to regulate its own temperature.
How much water should you drink during exercise/physical activity?
The fluid requirement varies from one person to another. The type of physical activity, duration and intensity of the activity, metabolic rate, humidity, temperature, level of physical fitness etc., impact how much water an individual may require.
However, here are some general guidelines for avoiding hydration during physical activity:
- Before you exercise:
- Drink about 500-600 ml of water at least 4 hours before exercising/playing a sport.
- Drink 250-350 ml of water about 10 to 15 minutes before exercise.
- While exercising
- If you are exercising for less than an hour, drink 100-250 ml of water every 15-20 minutes.
- If you are exercising for more than an hour, drink 100-250 ml of a sports drink (containing electrolytes and carbohydrates) every 15-20 minutes.
- After exercising
- While it is important to hydrate, you must ensure that you don’t drink too much fluid (more than 950 ml in an hour) while exercising, since “over-hydration” could also lead to side effects.