Effect on Metabolic Rate

Drinking 500 ml of water increased metabolic rate by 30% in healthy, normal-weight subjects. The increase of metablic rate occurred within 10 min and reached a maximum after 30-40 min. About 40% of the thermogenic effect originated from warming the water from 22 to 37 C. The total thermogenic response was about 24 Calories. It was estimated that drinking 2 liters of water per day would augment energy expenditure by approximately 96 Calories.

Boschmann M, Steiniger J, Hille U, Tank J, Adams F, Sharma AM, Klaus S, Luft FC, Jordan J. (2003). Water-induced thermogenesis. J Clin Endocrinol Metab. 88(12):6015-9.

Recommended Consumption

There is no magic number in prescribing the amount of water to consume throughout the day. The optimal amount varies according to body size, activity level, enviornmental factors, and diet. Drink just enough water thoughout the day so your urine is clear. Drink extra water before, during and after phyical activity or being exposed to higher temperatures. The goal is to drink before you get thirsty.

Effects of Dehydration

Dehydration of 3% of bodyweight can cause a 10% strength loss and 8% speed loss.

Fact or Fiction?

It has been theorized if not enough water is consumed, the kidneys do not function optimally, the liver takes over some responsibilities. The kidneys metabolize fat at half throttle.

Sports Drinks

If physical activity last longer than 90 minutes (eg: sports competition), choose a sports drink with electrolytes. For even longer durations, consider a beverage with electrolytes, carbohydrates and protien or amino acids.

Cold water is absorbed faster in the body; sugar slows absorption.

Water Intoxication

Hyponatramia, or water intoxication is a potientially fatal condition caused by consuming too much water. Excessive water consumption causes low sodium levels in the blood. Symptoms may include nausea, muscle cramps, comma, and even death. A runner died from the condition following the 2002 Boston Marathon. Another runner was in a comma for 4 days following a marathon in Jamaica.