As an athlete and a human being it is essential that we keep the body hydrated via the intake of fluids. Water is arguably the most important of all the nutrients we need, not least because around 60% of our body is water. It also aids many other vitamin functions in the body.

          Water is the transportation system around the body. It takes nutrients, oxygen, vitamins and minerals to where they are needed and takes waste products to excretory organs.

          Water is needed constantly by the body, so much so, that the balance within the body must be kept constant between very narrow limits in order for body metabolism and other functions to remain efficient.

          A loss of 2% body weight as water will seriously compromise your performance. A loss of 5% can be fatal. Water is constantly lost from our body throughout the day through breathing, sweating and as urine. As swimmers we must also remember that we still sweat in the water.   Therefore uptake of water is vital. Take for example a 60kg person (9st4lbs), 2% of that weight is 1.2kg. A litre of water weighs 1kg therefore that equates to a fluid loss of 1.2litres or 1200mls. Remember water loss at this level will mean slower metabolism therefore energy production to the muscles will become inhibited, lowered blood pressure leading to possible lack of sufficient blood flow to the brain which could materialise in poor concentration and tiredness. In general drastically reduced sub-optimal performance.

          An average human body will lose, at rest, between 2 ~ 2 .5 lites of water per day. An hour of exercise dependant on its intensity and conditions could be responsible for another 1 ~ 2 litre loss. It has been estimated that we can replace approximately 1 ~ 1.5 litres of water through the food we eat i.e.   fruit and vegetables for example, so it is not difficult to see that some active individuals i.e. Swimmers may have water needs of around 4 to 5 litres a day.  

          Water/ fluid levels can drastically be improved overnight, unlike a change in eating habits which would take a prolonged gradual approach. So now is the time to top up, drink and replenish at every opportunity (even whilst reading this document!). Regular toilet stops will be encountered but soon your body will adapt to the increased volume.

          Another point to bear in mind is the type of fluid we put into our body. Many believe their fluid intake is sufficient, but types of drinks could be making matters worse. For example coffee, tea, alcohol (not my swimmers) and many soft drinks, particularly those containing caffeine and aspartame, are diuretics (actively encourage water loss) and act directly in this way. Many pure fruit juices, although excellent in nutrient needs have too high a concentration of sugar in them to aid water absorption as they are hypertonic (more concentrated than the blood). This would force water to leave the blood and enter the gut by the process of Osmosis. For any drink to be useful as a re-hydrator it should be at least Isotonic (same concentration as the blood) or Hypotonic (lower concentration than the blood). To fulfil this criteria any sugary drink should not contain more than about 6gms of glucose per 100mls of fluid. This does not mean do not drink fruit juices, just think about watering them down.

          Lastly be aware that thirst is not a good indicator of fluid status and it is a response to dehydration, by the time you feel thirsty it is usually too late. It is also likely that when you drink your thirst value will be fulfilled long before you have re-hydrated fully.

          The bottom line here by far, water is your best fluid to drink and there are no advantages for hydration purposes of drinking commercially prepared bottled water as opposed to regular tap water. My advice, drink regularly throughout the day until you have reached the quota your body requires.     

 

Gary McCaffery

 

Head Coach ~ Buxton Swimming Club