How much water is enough?
Although uncommon, it is possible to drink too much water. Hyponatremis is a condition when too much water is consumed over a short period of time and the kidney does not have time to filter out the excess. This leaves the sodium concentration in the blood very low and symptoms can include headache, confusion, muscle spasms, nausea or in severe cases swelling in the brain cells. Electrolytes can be used to replace lost sodium stores and there are plenty well-known brands on the market.
Not having enough fluid can be serious and the importance during exercise of replacing water cannot be over stated. At 3% dehydrated an athlete will have inefficient kidney function, dry mouth, headache and a measurable reduction in exercise performance; at 5% heat exhaustion will result and require medical assistance.
1 liter per 1000 kcal you expend = your daily water requirement
How to assess hydration levels?
It is important to drink before you feel thirsty. When you feel thirsty you are already dehydrated and performance will be affected. It takes time for water to be absorbed into your body and transported. A good indicator is the colour of urine:
Sports drinks are an excellent way of improving performance by improving hydration and glucose replacement. Isotonic drinks contain the same amount of glucose as the body and are absorbed by the gut quicker (4gramms/100ml).
One of my biggest inspirations in life is my Father. A retired General Practitioner and fitness fanatic, he taught me years ago how to make my own isotonic drink with half fresh fruit juice, half water and a pinch of salt to encourage me to drink more. It really does the trick and by far cheaper than the shop bought drinks. Give it a try after a hard session and see for yourself.