No, not alcohol! Water. Dehydration can have a detrimental effect on performance so regularly drinking water is essential. Staying hydrated enables people to perform at their best by aiding concentration and reducing fatigue, and so can minimise injury risk. The amount you need to drink is individual and will depend on your sweat rates, the activity, length of time of activity and the weather.
Water is required for your body to survive and function, so being dehydrated can affect your athletic performance. Not drinking enough can negatively affect your mind and body, so consuming enough water before, during and after exercise is essential. There are several ways to find out if you're drinking enough, from special osmolality devices to simply looking at the colour of your urine.
Am I dehydrated?
If you feel thirsty, you are likely to already be slightly dehydrated. Drinking regularly throughout the day, before you actually feel thirsty is a way to avoid dehydration. Not going to the toilet regularly and the colour of your urine can also indicate dehydration. Urine should be a pale colour, but if it's a deep yellow, you aren't drinking enough water. Other common symptoms from not drinking enough are headaches, dry skin, dizziness, and fatigue. Even the slightest hint of dehydration can cause these symptoms and have a significant impact on sporting performance. Drinking regularly is vital to prevent these symptoms and allow yourself to perform well in sport.
How does dehydration affect the body?
If there's not enough water in the body, the blood will become thicker, so reducing in volume. As a result, blood flow decreases whilst the heart rate increases as it needs to work harder to maintain the blood supply. Blood supply is prioritised to working muscles and away from 'inactive' organs such as the skin, which can affect how the body controls temperature (thermoregulation). The body is less able to sweat and cool down so the core body temperature can rise to dangerous levels. Dehydration is particularly harmful in hot conditions so it is even more vital to drink often.
How can dehydration affect performance?
When doing any sport, you sweat, particularly in warm conditions. This loss of fluid must be replaced during and after exercise to minimise its effect on performance. When you sweat, you lose electrolytes and other nutrients as well as water, all of which are required for optimal performance. Carbohydrate sport drinks can help to replenish these, especially during a full day of competition or activities lasting over an hour.
Just a 2% decrease in bodyweight through loss of fluids affects endurance, fatigue and brain function. Fluid loss of 5% has been shown to reduce work capacity by 30% and even higher than this in long-distance runners with small percentages of fluid loss. Even slight dehydration can be damaging for athletes across all sports by having the following effects.
- Slower responses - Dehydration can slow down your neural pathways, which help send messages from the brain to the rest of the body. This will reduce speed, muscle reaction, and strength which would harm performance levels. Dehydration also affects concentration levels and attention spans which could result in delayed reactions and slow decision-making. These factors can all increase the risk of injury as the body isn't operating in full health. Even without injury risk, the effect of dehydration on the body could be the millisecond of difference in a race or in responding to a ball.
- Altered mood - An athlete's mood and emotional state can be affected by lack of water. Feelings such as anger, tension, fatigue, and lethargy can be increased through dehydration, which is not great for performance. Dehydration causes more cortisol, a stress hormone, to be produced that can affect performance by altering focus and attention. These changing moods could also lead to injury through poor decision-making or lack of concentration during activity.
- Greater fatigue - Dehydration causes the glycogen store in muscles to reduce quicker, affecting the muscles' strength and endurance. This means the body has less energy to fuel activities and so reduces the ability to perform well. The thickening of the blood and its decreased volume also restricts the delivery of nutrients, which impacts the body’s ability to recover. The risk of injury heightens with fatigue, so staying hydrated is essential to maintaining your health and optimum performance. Dehydration makes you tire quicker and this can make injuries more likely, particularly towards the end of an activity.
Educating, monitoring and advising athletes appropriately on fluid intake during training and games can have a positive impact on their performance, and is as important as the sports training itself.