“An ounce of prevention is worth a pound of cure”
1. Hydration for Health and Performance
“Water is the athlete’s most important nutrient”
The heading says it – Once the athlete, parent, and coach determine the fluid needs of the individual, they have accomplished the single most performance-enhancing aspect of sport nutrition.
Even a 1-2% fluid loss can cause significant performance deterioration by increasing core body temperature and causing early fatigue. A 3-5% fluid loss increases stress on the heart and decreases the ability to dissipate heat. By 7% collapse is likely, and the signs and symptoms of heat illness will be evident and the risk of heat stroke and catastrophic complications can follow.
It is not uncommon for players to dehydrate 2-6% during practice in the heat.
While training in Libya the players observed the Muslim belief in abstinence during Ramadan. During this time, they neither eat nor drink during the day. Professional soccer training is intense and during some of our two a day practices I could see many of the players lose coordination, speed, ball touch and intensity. At times even their speech became somewhat slurred. When they broke the fast with water, milk and dates it was like lifting a veil of haze away from the players. Their eyes became clearer and their ability to focus improved noticeably within just a few minutes. I was amazed at the profound effects dehydration and lack of fuel during the day had on the body during soccer training.
Rehydration with water alone may not be enough for the soccer player. Electrolytes play a role in the distribution of water throughout the body and also with muscle contraction and nerve conduction. Electrolytes are essentially tissue salts such as sodium, potassium, chloride and magnesium. Carbohydrates are sugars that the body requires for fuel during activity. Research shows us that the amount of carbohydrate in the drink has an effect on how quickly it is absorbed by the body.
In the 1970’s, an English physiotherapist gave his team either water or a sport drink with a crazy amount of carbohydrate (46% concentrated glucose syrup). He found that when the team drank the supplement rather than just water, they scored more goals, gave up fewer goals, and had more ball touches and more shots on goal, especially in the last one third of the game.
Twenty players from the Sao Paulo Futebol Clube were divided into two groups – one group played a soccer game without ingesting any additional fluids (as was their normal practice) and the other half drank a sports drink with 6% carbohydrate-electrolyte mix every 15 minutes throughout the game. The group who drank lost less body weight and performed more sprints than the non-drinking group. The group who drank also had lower body temperatures and lower heart rates than the non-drinking group although these values were not statistically significant.
In a smaller study, 9 players drank either a sport drink (6.9% carbohydrate) or a placebo. The players drank 5 ml of fluid for every kg of body weight, and another 2ml/kg every 15 minutes afterwards. Players did performance tests 7 days apart: when they consumed the carbohydrate beverage they ran 33% longer than when they drank the placebo. Another study showed a 37% improvement in time to fatigue during running, a faster 20 m. sprint during the last 15 minutes, improved motor skills near the end of exercise, and a lower perception of fatigue.
Signs of Dehydration:
- Reduced endurance
- Earlier onset of fatigue
- Less alert or difficulty with concentration
- Muscle cramps
- Heavy sweating
- Increased heart rate
- Decreased skin elasticity
- Player’s urine darker than a pale yellow
Prevention is better than cure as the saying goes. A soccer player should ensure proper hydration of the body begins at least 24 hours before training or game day.
If your player does become dehydrated or starts getting muscle cramps then get them off the field and try to rehydrate them with a sodium containing fluid, plain water, or a very diluted sports drink. Usually, by the time muscle cramps begin, the player is pretty far gone and will often have recurring cramps until removed from the field and rehydrated.
After dehydration, and depending on conditions, heat exhaustion can occur. This is a more serious matter (details in Chapter 8).
How Much Should the Athlete Drink?
The simplest way to evaluate an athlete’s hydration status is to monitor the color of his or her urine. A pale yellow color indicates adequate hydration while a darker color similar to apple juice indicates dehydration. This should be monitored well before the day of competition to determine one’s individual hydration requirements. After a few weeks the athlete can note a pattern and approximate sweat rate per hour.
The preferred method of determining an athlete’s hydration needs is to weigh the athlete before and after a practice or game. Sweaty clothes should be removed before weighing. The Sports Medicine Committee for US Soccer recommends that athletes should aim to drink enough fluid so that their body weight after the workout is within 1 kg (2.2 lb) of their starting weights.
To replace the water, drink one pint of fluid for every pound lost. (One pint = 16 ounces = 500 ml = 0.5 liters). It is critical to replace the water loss as quickly as possible. Before the next workout, bodyweight should be back up to the baseline level.
There is a formula for fluid ingestion although it is always better to determine individual needs. The general formula for daily water intake is as follows:
• 1/2 ounce of water per pound body weight (normal activity)
Or
• 2/3 ounces of water per pound body weight (for athletic individuals)
Remember that fluid requirements will go up further as the relative humidity and temperature go up, as exercise intensity increases, in windy conditions, at altitude, and if the athlete wears additional layers of clothing; relatively unfit individuals will require more fluids than fit individuals. It is also important to remember that most foods contain water and all drinks contain water (Sport drinks are 94% water, milk is 90% water, juices are about 89% water). Once again, water is the athlete’s most important nutrient.
The Young Athlete
Proper hydration is essential for the safety of active children. A child's body surface area makes up a much greater proportion of his overall weight than an adult's. Children do not regulate body temperature as efficiently as do adults. Therefore, active children are more susceptible to heat stress and illness. Heat injury, usually complicated by dehydration, is one of the most common sports injuries among kids, but is the most preventable.
Children should be encouraged to drink fluids frequently during activity – even though they may not be thirsty. A general guideline is that kids under 90 pounds should drink 3-6 ounces of fluids 1 hour prior to activity and 3-5 ounces of fluids every 20 minutes during activity. Kids greater than 90 pounds should drink 6-12 ounces an hour before and 6-9 ounces every 20 minutes during the activity. After activity, the young athlete should drink 16 ounces (1 pint, or 0.5L) for every pound of body weight that is lost. Again the important message here is that pre- and post-workout body weights or urine observations should be considered early on so that individual fluid needs can be assessed.
Don’t Rely on Thirst
Athletes do not drink enough fluid when they rely solely on thirst. This phenomenon is called voluntary dehydration and although it is not totally understood why the thirst mechanism does not keep up with demand, it is clear that performance suffers if the athlete is allowed to dehydrate during activity
A regular hydration schedule should be implemented for all teams so that athletes fall into the hydration habit.
Is There Such Thing As Too Much Water?
Hyponatremia means a low concentration of sodium in the blood. This is a relatively rare condition where sweat (water and salts) is replaced by water (no salts), causing an eventual decrease in salt concentration. This condition is probably most often seen in ultra endurance events such as triathlons and marathons. One estimate places 30% of Hawaii Ironman finishers as being both dehydrated and hyponatremic. This is one of the foundations for athletes taking sport drinks as their method of rehydration.
Symptoms of hyponatremia may include: muscle cramps, swelling of the hands and feet, nausea, disorientation, confusion and slurred speech. Progression can be life threatening. These symptoms are similar to heat stroke and simply drinking water can actually worsen the condition. The main difference between the two conditions is in core body temperature which will be elevated during heat stroke (> 40°C or 104°F) while is less than 40°C during hyponatremia.
Sport Drinks
Depletion of the body's carbohydrate stores and dehydration are the two main factors that will limit prolonged exercise. The higher the carbohydrate levels in a drink the slower the rate of stomach emptying. Isotonic drinks with a carbohydrate level of between 6 and 8% are emptied from the stomach at a rate similar to water. Electrolytes, especially sodium and potassium, in a drink will reduce urine output, enable the fluid to empty quickly from the stomach, promote absorption from the intestine and encourage fluid retention.
According to Carol Rodgers of University of Toronto’s Faculty of Physical Education and Health, these people may have the right idea. "Sports drinks do help to delay fatigue symptoms." Sports drinks were originally formulated to enable people to rapidly replenish the fluids and electrolytes lost through sweating during activity, she says. "So, the most common sports drinks on today's market contain a combination of electrolytes such as sodium, chloride, potassium and magnesium, various forms of sugars at a five to eight per cent concentration, and flavoring."
For energy replacement, it is the sugar, or glucose component of the drink, that is the most important. "Glucose is the primary source of energy for the brain, red blood cells and parts of the central nervous system," she says. "If glucose is low, it can cause dizziness, fatigue and mood changes." But in exercise, she notes, glucose is taken up from the blood plasma into the working muscles, forcing the liver to then break down its stored glucose (glycogen) and release it into the plasma.
Eventually, as the liver's glycogen stores become depleted, fatigue sets in and there is a decrease in the ability of the individual to continue exercising. "Glucose from sports drinks raises the blood glucose level of the body, in turn helping to maintain liver glycogen stores and preventing fatigue."
Rodgers also notes that while sports drinks were originally thought to benefit only those involved in activities of a long duration (where there would be sufficient decreases in liver and muscle glycogen), recent research suggests that the drinks may also help to maintain exercise intensity during short-term and "stop-and-go" activities. "Consuming a sport beverage during team activities such as basketball, hockey and soccer may help athletes to perform at a higher intensity after breaks as well as possibly result in a greater overall level of performance.
However, Rodgers warns, sports drinks are not a good replacement for plain water when athletes are overheated and dehydrated. "During activity in hot environments - when fluid replacement is essential to ensure that dehydration does not occur - consuming water or a diluted sports drink is your best choice."
Rodgers offers some tips for first-time sports drink consumers. "First-time users of sports drinks often find them too sweet, so it's good to dilute them by 30 or 50 per cent. A diluted drink still provides some of the energy benefits as well as more flavor than water alone."
Homemade Isotonic Sports Drink Recipes
Drink one: No Frills
- 5 tablespoons of table sugar
- 1/3 teaspoon of salt
- 1 liter of water
Drink two: Fruit Academy
- 200ml ordinary concentrated fruit juice
- 800ml water
- A pinch of salt
Drink three: Sport Academy Thirst Burst
- 500ml unsweetened fruit juice (orange, apple, pineapple)
- 500ml water
- Mix them all together in a jug and cool down in fridge.
Conclusions and Recommendations:
- Once the athlete and coach determine the fluid needs of the individual athlete, they have accomplished the single most performance-enhancing aspect of sport nutrition.
- Begin prehydrating the body at least 24 hours before the activity begins. Continue prehydration by drinking 5 ml. per kg body weight 1-2 hours before the game.
- Establish a hydration schedule for regular fluid replacement during games and practices. If possible 5-6 sips (or 2 ml/kg) every 15 minutes is ideal.
- After the game replenish lost fluids, electrolytes, and carbohydrates as quickly as possible.
- Weigh athletes before and after activity to determine individual fluid replacement needs.
- For every pound lost during activity, drink 1 pint or 500 ml. of fluids.
- Keep water bottles and/or sport drinks close by so athletes can easily hydrate during activity or competition.
- Educate athletes and coaches regarding the prevention, recognition and treatment of dehydration and heat related illnesses.
|
