Water and Hydration for Performance

The Importance of Water 63% of total body weight is from water 37% of total body weight is from water inside cells 24% of total body weight is from water outside the cells 5% of total body weight is from the water that makes up blood plasma Well hydrated muscles are about 75% water Bones are about 32% water Fat has very little water 10% Blood is about 93% water

Water Balance Maintaining the correct water balance is very important. Proper water balance allows for: nutrients and waste to be transported allows for chemical reactions to take place aids digestion and absorption helps to regulate body temperature Each day you lose water in a number of ways it must be replaced as it is lost. In order to maintain a balance between the water you consume and the water that is lost each day, you need to consume: Approximately 1 milliliter of water taken in for every calorie that is burned This equals a minimum of 8 cups of fluid/day

Dehydration and Rehydration Dehydration (water loss) resulting in a loss as little as 2% of body mass can adversely affect a variety of physiological functions and lead to performance decrements. Of particular importance is the association of dehydration with inadequate thermal regulation (body temperature). Dehydration can turn into a serious heat illness; heat exhaustion, heat stroke which can potentially lead to death. Dehydration during exercise should be avoided. Physical activity creates heat and heat must dissipated for an athlete to continue performing an activity

Dehydration and Rehydration 2 primary systems for dissipating or losing heat: 1. Moving more blood to the skin to allow heat dissipation through radiation. 2. Increasing the rate of sweat production One of the main mechanisms we have for dissipating heat is to produce sweat, which cools the body down as it evaporates off the skin. The inability to produce sweat causes the body to overheat. Unless water replaced through sweat loss is replaced the rate at which one sweats will be reduced and body temperature rises. Athletes must drink enough fluids to sustain the sweat rate.

Dehydration and Rehydration Most athletes lose substantially more body fluids through sweat than they replace by drinking during exercise. This so-called “voluntary dehydration” can have serious implications for health and performance. An athlete’s failure to drink sufficient fluids is caused by many factors, including the physiological inhibition of thirst that occurs after moistening the mouth with a beverage, the uncomfortable sensation of fluid in the stomach, poor access to beverages during exercise, poor quality of available beverages and a lack of education about the need to drink during exercise

Dehydration and Rehydration After becoming dehydrated, elderly individuals tend to drink less than their younger counterparts Athletes can be trained to become better drinkers before, during and after exercise Improving the flavour of a beverage can dramatically increase the consumption of fluids during exercise Although athletes will drink more of a cool beverage than a warm one, the temperature of the drink has no important effect on core body temperature.

Drinking behaviour The drinking behaviour of humans is very complex. Many athletes avoid rehydration even though they are aware it is likely to improve performance. The volume and frequency of drinking in humans is determined not only by the physiological signals in our bodies that tell our brains when it’s time to start or stop drinking but also by psychological factors as well: · Types of beverages · Location of beverages (if they are close the athlete drinks if they are far the athlete will pass) · How athletes are educated · Flavour of beverages

Voluntary Dehydration Voluntary Dehydration can be explained by the various drives our body has to start and stop drinking. Part of the drive to drink arises from low blood volume. A hormone is released vasopressin. Once someone begins drinking, neural receptors in the mouth and pharynx trigger reflexes that begin to suppress the release of vasopressin and this in turn reduces thirst drive. This helps someone from drinking too much too fast causing low sodium levels (hyponatremia) Also athletes may stop drinking before they are rehydrated. By the time this thirst drive is felt the athlete is already in a state of dehydration.

Tips on Drinking During Exercise Here are some ideas that can help improve your fluid intake during exercise: Determine your typical “fluid shortfall” during exercise by measuring your body weight before and after practices and competitions with your normal fluid intake (Measure your fluid intake too). For each pound of weight you lose during the exercise period, your fluid shortfall is about 16 oz. For example, if you lose 3lbs during a 2- hour training session you have sweated away 3lb x 16= 48oz more of fluid than you have consumed. Your body can adapt to increase fluid intake, so during future training sessions, gradually increase your fluid intake- even if you don’t feel thirsty- until you can replace at least 80% of your sweat losses during exercise Use an alarm wristwatch or some other method to remind you when it’s time to take a drink Ask athletic trainers, teammates, or friends to have drinks available at appropriate places and times during training and competition

Tips on Drinking During Exercise · Experiment with different beverage containers to determine which ones makes it easier for you to drink while exercising. Some athletes may do better with squeeze bottles others with wide mouth · Drink smaller volumes more frequently to minimize stomach discomfort · Choose a beverage that tastes good conatins carbohydrates plus a small amount of sodium chloride. The carbohydrate can help improve performance and the sodium is important to minimize dehydration and maintain body sodium balance. · Drink more spit less

Indicators for dehydration Urine: colour and frequency Darker colour is a dehydration indicator the darker the worse the dehydration Low frequency is also an indicator the lower the frequency the worse the dehydration Hydrated= clear urine over the course of a number of times in the day 3-5x’s

Serious Problem Indicators: Heat Illness Dizziness Lightheaded Loss of motor skill Body temperature rise Dry mouth Heart rate Loss of bodily function Vomitting

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