Hydration PDF

 HYDRATION: Hydration = The process of providing an adequate amount of liquid to bodily tissues. Dehydration = A condition that can occur when the loss of body fluids, mostly water, exceeds the amount that is taken in. Dehydration is when we are los...

 HYDRATION: Hydration = The process of providing an adequate amount of liquid to bodily tissues. Dehydration = A condition that can occur when the loss of body fluids, mostly water, exceeds the amount that is taken in. Dehydration is when we are losing more fluids than we are taking in. We don't say 'drinking' because you also hydrate yourself with the foods you eat. There is water in fruit etc and the body absorbs that. Thermoregulation, Exercise, and Thirst: Definition: Thermoregulation is the way in which the body is able to maintain a consistent internal temperature, regardless of changes in external temperatures caused by the environment. 'Thermo' relates to temperature and 'regulation' relates to keeping control. The body to work efficiently needs to maintain a certain temperature of all the internal organs. Even if we were to go to the north pole where it is freezing, the internal temperature of the body needs to stay the same and the body will react and do things to make it happen for example when we are cold, we start shivering. By shivering your muscles are activated to try and warm you up. Thermoregulation is an involuntary function. We have no control of what happens inside our body with regards to maintaining its temperature. Exercise impacts on the body's ability to control temperature. This affect will vary depending on conditions like heat or humidity. When we exercise, we get warm, our body temperature goes up. If we exercise on a really hot day, then our body temperature will go up even more and so the body then reacts to try cool you down e.g sweating. Thirst is normal. All humans, when their fluid levels are low, will crave water or other fluids. The thirst mechanism cannot be shut down. It is automatic. A person cannot survive for more than 3 or 4 days without water, although they may survive as long as 30 days without food. The thirst mechanism does not activate until the body supply of water is depleted by approximately 500ml. Of the water consumed daily in various forms, a sedentary person will eliminate 1,500ml as urine, 500ml through evaporation and perspiration, 300ml through the lungs and 200ml through the digestive and other gastrointestinal processes. An athlete involved in a demanding workout or who is active in warm weather may lose between 1-4 litres of fluid through perspiration in less than 90 minutes of activity. The fluid losses outpace the thirst mechanism, putting athletic performance and athlete health at risk. This means that they are losing water too quickly and the whole mechanism in the body that detects dehydration and body temperature can't work fast enough - so fluid loss (sweating) outpaces (is faster than) the thirst mechanism. An athlete can begin to feel the effects of dehydration, which include impaired cardiovascular function, impaired muscle function, and loss of coordination and motor control, before the thirst mechanism has even been signaled. If an athlete relies on the thirst sensation to determine hydration, the athlete will often begin the activity in a mildly dehydrated state. Because the thirst mechanism is an unreliable indicator of the body's thermoregulatory condition during exercise, an athlete must develop a fluid replacement/hydration strategy that ensures optimal function regardless of the thirst sensation. Athletes need to plan when they are going to drink and what - just like they plan their training session. Drinking water before, during and after the performance is important. When the athlete is exercising for longer than 1 hour, drinking sports drinks that maintain the sodium level is important. Sodium is an important factor in how the body maintains fluid levels. Why? - Fluid loss decreases plasma volume (The blood that is liquid). - The decrease in plasma causes a decrease in BP. - The decrease in BP reduces blood flow to the muscles and skin. In order to overcome this, heart rate increases. Because less blood reaches the skin, heat dissipation (lose heat) is negatively affected and so the body retains more heat. The muscles need more oxygenated blood and if the blood isn't flowing fast enough then the heart needs to beat faster to push more blood out. The heart is already beating fast when you exercise and now it needs to beat even faster than that. And because of this less blood is now going to the skin to try and cool the body down and the athlete gets hotter and sweats more and loses more fluid and so the cycle continues. In warm weather when dehydrated, drinking water without proper sodium levels, can lead to a state where the water will not be absorbed into the body because the involuntary systems try to maintain a sodium balance with the sodium remaining. When exercising a lot the athlete needs to drink something with sodium in it to replace what was lost while sweating. An imbalance within the body means that if the athlete drinks just plain water it won't be absorbed so the athlete isn't benefiting. This condition is called hyponatremia, a state of water intoxication - they have too much water in the body. Hyponatremia: Exercise hyponatremia is the result of: - Overconsumption i.e, drinking too much. - Under-replacement of sodium losses i.e. not drinking or taking in sodium. - Or both i.e. drinking too much water but not taking in sodium. This is still a fairly new condition and not enough research has been conducted. The first cases were only reported in the 1980's and only a small number of cases have been reported. Symptoms of hyponatremia: - Bloating - Vomiting - Nausea - Headache - Brain swelling (Cerebral Edema) The ideal way to prevent hyponatremia is to replace water at the exact rate that it is lost or to add sodium in the fluid being drunk. An athlete needs to drink an energy drink with sodium in it or if they are drinking water only then they need to drink the exact amount of water that they are losing. No-one can work this out while playing sport so rather drink an energy drink with sodium in it. One problem is that sports drinks don't contain enough sodium. It differs from drink to drink. Energade - 32mg per 100 ml Powerade - 31mg per 100ml Lucozade - 24mg per 100ml And that's why top Comrades marathon runners will mix their own drinks and have someone along the road to give it to them. Hydration is such an important aspect of performance that it must be planned, rather than just being an afterthought - Pre-hydration is the period leading up to an event. A healthy person will consume approximately 1,8 litres of fluids daily. An athlete may adjust this as the event approaches. Pre-hydration will also include the fluid consumed on the day of the event prior to competition. - Hydration means consuming fluid during the competition, using either water or sport drinks with electrolytes or carbohydrate elements.