Hydrate to elevate

Staying hydrated is one of the most important components of being able to perform and live life at your highest potential. It is also one of the most overlooked components of sports nutrition – with macronutrients like protein, carbohydrates and fats stealing all the limelight, we often forget about the nutrient that our body is composed of 60 – 70% – water.

First of all, what is hydration?

Hydration is providing your body with adequate fluids and electrolytes to perform the chemical reactions needed to sustain life and perform at your best. Water is essential to maintain blood volume, regulate body temperature and allow muscle contractions to take place. When you train, the main way the body maintains optimal body temperature is by sweating. Heat is removed from the body when beads of sweat on the skin evaporate, resulting in a loss of body fluid.

Sweat rate

An average person sweats between 0.8 to 1.4 liters per hour during exercise. However, this rate is different for different people, and also depends on the type of exercise you do, the temperature and the humidity.

An extreme example is the endurance athlete Alberto Salazar, who has one of the highest sweat rates known to date – up to 3.7 litres per hour while training for the 1984 summer Olympics.

Dehydration

Did you know that studies has shown that a 2% loss in body weight through sweat causes a marked decrease in performance? A loss of greater than 2% can lead to nausea, vomiting, diarrhoea, and other gastro-intestinal problems during exercise.

Dehydration reduces the rate of fluid absorption from the intestines, making it more difficult to reverse the fluid deficit. If you take too long to replenish fluids in this state, you may feel bloated and sick. Training and “toughening” your body to handle dehydration is therefore not really helpful.

Your body on dehydration

• Muscle fatigue
  muscles become fatigue and lose strength, and there is also decreased muscle growth and repair, possibly hampering strength gains.
• Decreased blood flow and changes in circulation
  during dehydration your blood volume decreases, which means your heart has to work harder to provide working muscles with enough blood, which in turn increases your heart rate. The viscosity of your blood – how thick your blood is – will also increase, making your heart and circulatory system work harder.
• Reduced mental function
  feelings of dizziness, flatness or fatigue has an impact on intensity, perceived effort and even skill levels, for example in team sports like rugby or sports like golf.
• Increased body temperature
  without enough fluid to cool down your body when it gets too hot, reduced sweating can cause body temperature to rise and lead to premature fatigue.

How do I know if I am dehydrated?

• Monitor weight losses before and after exercise – 1kg loss in weight = approx. 1L sweat or fluid lost.
• Monitor your urine. Dark coloured, strong smelling urine is a good indicator that you need to up your fluids.
• Skin pinch test – using your index finger and thumb, pinch some of the skin on your arm or hands. If it takes a while to rebound back, you may be dehydrated.
• Other indicators can be a bit more subtle – like general feelings of tiredness or fatigue, dry eyes or a dry mouth.

*You can download the Health Elevation Dehydration Checklist by clicking on the link below – keep it at hand to remind yourself of the warning signs of dehydration!

Download HE-Dehydration-checklist

Can you drink too much water?

Yes! While hydration is important to optimise performance, it is also important to not over-do it. Overhydration can lead to a condition known as hyponatremia, otherwise known as low sodium levels in blood. The symptoms of hyponatremia is quite similar to that of dehydration – headaches, dizziness, nausea and vomiting.

How much should you drink?

This depends on the duration and intensity of the activity, your sweat rate and also individual electrolyte and fluid needs. Like most aspects of sports nutrition, there is no “one size fits all” approach to fluid intake. In the table below you can find a rough estimation of what fluid needs might look like:

Timing	Fluid needs
Before	10ml/kg body weight up to 2 hours prior to exercise.
During activity <60min	Not always necessary – however, in extremely hot conditions or intense sessions, aim for a generous sip or two every 15-20 minutes if possible.
During activity <60min	About 200 – 250ml every 15 – 20 minutes depending on how well your gut responds to fluid.
After	Try to replenish at least 100% the amount of fluid you lost in weight during exercise. A loss of 1kg weight = 1 litre fluid

Water or sports drinks?

For exercise lasting less than an hour, plain water should be sufficient.

The ISSN (International Society of Sports Nutrition) recommends that, for exercise lasting longer than 60 minutes and especially beyond 90 minutes, athletes should take in glucose/electrolyte solutions (something like 32Gi, Powerade, Game, etc.) to:

• Maintain blood glucose levels
• Prevent dehydration
• Reduce the immunosuppressive effects of intense exercise

Alternatively to commercial sports drinks, you can also consume fruit juice that is a bit diluted with a pinch of salt to make your own glucose/electrolyte solution.

Final note

It is important to remind yourself to drink water throughout the day, not just while you are training. You can do this by putting reminders on your phone or carrying a bottle of water with you wherever you go.

Hydrate to elevate.

References:

1. 1. Murray, B. (2007) Hydration and Physical Performance J. Am. Coll. Nutr. 26: (5) 542S- 548S.
2. 2. Sawka M.N., Burke L.M., Eichner E.R., Maughan R.J., Montain S.J., Stachenfeld N.S. (2007) ACSM Position Stand – Exercise and Fluid Replacement. Med. Sci. Sports Exerc. 39: 377-390.
3. 3. Fact Sheet, Fluid in Sport, Sports Dietitians Australia, May 2011.