On the surface it might appear that this topic does not have a lot to do with statistics and science. This however changes when you take a closer look. It has a lot to do with food science and human nutrition, although hydration is still part of psychological research. Therefore I encourage you to carry on reading.
The water makes up to 60% of the human body weight (Guyto ,1976). Therefore it is extremely important to keep the fluid level in the body at a right level. Only 1% of dehydration (1), can cause performance to drop by even 10%. This includes decreased physical and mental performance, decreased concentration, headaches, increased heart rate, increase/ decrease of body temperature and discomfort. People who exercise while dehydrated put themselves at risk of different kinds of injuries.
Other than general well being water also have some long term impact on human body’s. The most obvious is that it filtrates the body, especially the kidneys. It is a perfect way for the organism to get rid of wastes and bacteria that can cause different diseases. It has been shown that regular consumption of water helps to prevent cancers (2). On top of this water plays a key role in the digestion system. Keeping the right level of fluid in the organism will make the digestion system to work better, will decrease the feeling of hunger (which will result in eating less undesirable food), and
There is also a downside to drinking water. One of them is having to visit toilet frequently (which is a real pain because I need to make a brake every 20 minutes when writing this blog after I had 5 liters of water so far today…), and the other one is a condition called hyponatremia. It is a result of drinking too much water, which causes the sodium in the body to become diluted, and causes the cells to start swelling.
In their study, Ciab et. al, tested 8 healthy endurance trained men. Their conditions were: euhydrated (normal state of body water content), dehydrated (up to a weight loss of 2.8%), and hyperhydrated (with a solution containing glycerol having ingested volume equal to 21.4 ml/kg of body weight). The subjects were assigned to a pedaling exercise and were administered psychological testing of psycho-motor skill, perceptive discrimination, fatigue, memory and mood. The dehydration conditions impaired cognitive abilities. After an arm crank exercise, further effects of dehydration were identified for tracking performance. Also long term memory was impaired in hydration and control situations, but no decrement in performance in hyperhydration group.
There are countless benefits of drinking water however I am a little restricted by time, and the number of words I put in this blog, as nobody would probably read it. The simplest conclusion for this topic therefore is: Want to feel better? Drink 2 to 3 liters of water a day.
Guyton, Arthur C. (1976). Textbook of Medical Physiology (5th ed.). Philadelphia: W.B. Saunders. p. 424.
‘Foods, Nutrition and Sports Performance,’ ed. C. Williams and J.T. Devlin (1994), pp 147-178
‘Clinical Sports Nutrition,’ ed. L. Burke and V. Deakin (1994), pp 333-364
E.F. Coyle (1994). ‘Fluid and carbohydrate replacement during exercise: how much and why?.’ Sports Science Exchange, 50, vol. 7, no. 3
Maughan, Leiper & Shirreffs (1996). ‘Rehydration and recovery after exercise.’ Sports Science Exchange, 62, vol. 9, no. 3
C. Cian., N. Koulmann., P. Barraud., C. Raphel., C. Jimenez., B. Melin,. (2000)., Influences of variations in body hydration on cognitive function: Effect of hyperhydration, heat stress, and exercise-induced dehydration. Journal of Psychophysiology, Vol 14(1), 2000, 29-36. doi: 10.1027//0269-8803.14.1.29