Starting any bout of exercise hydrated is key. Why? Because water is essential to maintain blood volume, regulate body temperature and allow muscle contractions to take place. The detrimental effects of dehydration on performance include:
- loss of coordination
- impaired decision making
- reduced power and strength
- increased perceived rate of exertion and;
- increased risk of heat stress
How can I hydrate pre-game/race-day?
Hydration is very individualised as it depends on what you have done that day (i.e. exercise), the environment (i.e. hot or cold climate) and what you have eaten that day (i.e. high sodium foods, hydrating foods). Generally speaking, you need to drink a couple (1.5 to 3 depending on size and daily activity levels) of litres of water the day before game day, and then the morning of and ensure your urine is no darker than a pale yellow. However, please keep in mind that certain beverages such as berocca can change the colour of your urine.
Hot tip: Remember to weigh yourself before the game/race so you can rehydrate effectively after it with appropriate amounts.
How do I hydrate during the game/race-day?
During exercise, the main way the body maintains optimal body temperature is by sweating via evaporative heat loss. Therefore, we must replace these losses for optimal performance. Typically, the rates of sweat loss are higher during exercise than the rate you can drink, so most athletes go into fluid deficit. It is advised that you drink fluid during exercise to reduce this fluid deficit and potential performance detriments associated with dehydration.
How much fluid do I need to lose before my performance is impacted?
Again, sweat loss, and its effect on performance, is very individualised. However, research shows that reductions in body mass of 3–4% through fluid loss in competition appear to consistently attenuate/reduce:
- strength (by ∼2%)
- power (by ∼3%) and;
- high‐intensity endurance (by ∼10%)
This is suggesting that alterations in total body water do affect some aspect of muscle force generation (Judelson et al. 2007).
Another study found that 2–7% reductions in body mass significantly reduce endurance
exercise performance, particularly in environments that are warmer than 30°C (Cheuvront et
al. 2003). Consequently, if you are an 80kg male this means that you only need
to lose ~1.6kg to start experiencing serious detriments to your performance.
1. Ensure that you drink at a rate that is comfortable
2. Practice your competition fluid intake plan in training sessions. Get to know your sweat rate by weighing yourself before and after training sessions and competition
3. Water is an excellent fluid for low intensity and short duration sports
4. Sports drinks are ideally suited to high intensity ‘stop-go’ and endurance sports as they contain fluid, electrolytes and carbohydrates
5. If you are exercising in hot conditions you should drink cold fluids to cool down your body temperature
6. It is possible to over-drink during exercise – drinking an extreme amount of water in a short period of time can cause your blood sodium to drop too low, known as hyponatremia. Hyponatremia is a very serious condition and can be fatal. This once again highlights the importance of getting to know your sweat rate and knowing how much you should be drinking
Weigh yourself and replace losses by 150%. For example, if you lost 1kg in weight you will need to drink 1.5L of water to rehydrate post-game.
For an individualised fluid plan contact the team at Absolute!
Written by Atlanta Miall (APD, AN, AccSD)
Judelson DA, et al. Hydration and muscular performance: does fluid balance affect strength, power and high-intensity endurance? Sports Med. 2007;37(10):907-21