Nutrition strategies taken up by athletes should promote optimal performance. They should address all the factors that can cause fatigue and decreased output during the end of any performance. Some factors that can affect performance output of an athlete include dehydration, electrolyte imbalances, glycogen depletion, hypoglycemia, gastrointestinal discomfort and imbalance in acid-base ratio. Fluids or supplements taken before, during and after any sporting event can delay or prevent the attack of these factors.
Hydration Tips for Fluid & Electrolyte Balance
Staying hydrated is important for optimal health and exercise performance. Apart from every day fluid losses from respiration, gastrointestinal, renal and sweat sources, athletes need to take care of sweat losses that occur greatly due to performance in an event or while training. Sweating and dehydration though used interchangeably have a slight difference in meaning. Sweat is the by-product of muscular work (hypovolemia) aggravated by environmental factors while dehydration is the process of losing water content in the body resulting in hypohydration.
Apart from water, sweat contains major quantities of sodium with lesser amounts of potassium, calcium and magnesium. The fluid needs gain more prominence or less prominence depending on the athlete’s body type, type of exercise and the environment.
Different fluid deficiency ranges can affect different abilities:
Some athletes might be hypohydrated before exercise purposefully, due to longer training sessions or multiple events in a day that can affect their performance greatly. It is recommended that athletes consume fluids (or include sodium in pre-exercise fluids and foods) equivalent to 5-10 ml/kg BW some 2-4 hours prior exercising to get the pale-yellow coloration of urine. Some athletes try to hyperhydrate before exercising during hot weathers which can lead to ample sweat loss or sometimes, restrictions imposed on fluid intake can lead to fluid deficits. Athletes use glycerol and other plasma expanders for this purpose and this has been banned by the World Anti-Doping Agency.
Hydration While Exercising
Every person expels sweat at different rates based on exercise intensity, duration, fitness, heat acclimatization, altitude and other environmental factors as well. Book wise, athletes are expected to drink enough fluids to replace sweat losses and maintain fluid deficit to <2% BW. Sometimes, the athlete might be careless and ignore consuming fluids while exercising and at other times certain other factors may impair fluid availability or opportunity to consume them during exercise. Generally, when high caliber athletes train, sweat loss exceeds fluid intake. While the base rule of sweat loss remains the same for athletes, differences in drinking behavior and sweat rates of athletes can result in anything from dehydration to over-hydration.
A loss of 1kg BW represents 1L sweat loss. Normally, athletes should consume 0.4 to 0.8 L/h, but the quantity might be slightly high or low depending on the athlete’s tolerance, experience, availability of time for fluid consumption and benefits of consuming other nutrients in liquid form. Athletes can choose flavored cold beverages to increase self-induced fluid intake.
Earlier athletes used to reach fluid deficit rates over the course of training and during the past 2 decades, this scenario has changed. It has improved such that, some recreational athletes exceed their sweat loss rates and over-hydrate resulting in water intoxication and hyponatremia. This scenario is typically seen in recreational athletes compared to competitive athletes whose opportunity and belief to drink are greater. Athletes ending up with hyponatremia experience nausea, vomiting, bloating, puffiness, headache, confusion, weight gain, delirium, respiratory distress, seizures or even death, if left untreated.
Skeletal muscle cramps in athletes may be due to hypohydration and electrolyte imbalance. Athletes who have the tendency to sweat more, especially when sweat is laden with sodium are at a greater risk of cramping.
Most athletes near their end of training practice with fluid deficit and may need to restore euhydration during recovery. Rehydration generally includes drinking water and including sodium at a modest rate that minimizes urinary losses. Consuming sodium helps to retain ingested fluids and it is highly irrational to advise an athlete to restrict sodium intake post-workout schedules. Effective rehydration includes consuming greater volumes of fluid (125%-150%) than final fluid deficits. Also, excessive consumption of alcohol during the recovery period is not appreciated considering its diuretic effects.