Drink up

Friday, 27 November 2015 901 Views 0 Comments
Drink up

By Prachi Mandholia

Here’s how you can stay hydrated, spot signs of dehydration and choose between water or sports drink while on a long run

For a runner, hydration is directly proportional to performance. The evaporation of sweat through the skin’s surface is a natural cooling mechanism that helps to release any excess heat from the body. It is important that the fluids lost through sweat be replaced well in time and a runner must stay hydrated before, during and after the run. Hot weather makes a runner more susceptible to dehydration, so sipping water throughout the run is a great way to keep the body temperature normal.


Dehydration is the acute change in fluid levels that goes from normal to less than normal. Since the human body constitutes approximately 70% water, a significant decrease in fluid level will alter physiological functions. During high intensity activity, as exertion increases, there is an increase in sweat rate too. If fluids are not accessible at such times, dehydration occurs.

Warning Signs of Dehydration

  • General Discomfort
  • Headache
  • Weakness
  • Dizziness
  • Muscle Cramps
  • Chills
  • Nausea
  • Vomiting
  • Fatigue

It is important to remember that drinking excess fluids can cause over-hydration, a condition also known as hyponatremia, or low levels of sodium in the blood. It occurs when there is fluid overload and under-replacement of sodium. As sodium is also lost through sweat, it is important for the runners to get enough sodium before, during and after the run. Hyponatremia is more common among slow runners who drink excessively during the four hours of run.

Warning Signs of Over-Hydration or Hyponatremia

The symptoms of over-hydration are very similar to dehydration

  • Headache
  • Muscle Weakness
  • Nausea
  • Vomiting
  • Disorientation
  • Confusion

How Much Water Does A Runner Require?

To determine your unique fluid needs, estimate your sweat rate:

  • Do a warm-up run to the point where you start perspiring
  • Urinate if necessary
  • Weigh yourself without clothes
  • Run for 1 hour at similar intensity and conditions of the run
  • Do not drink any fluids during the run
  • At the end of the run, weigh yourself again without clothes
  • The difference in the weight (ounces) is your hourly sweat rate
  • It is the amount of fluid that should be replaced each hour of the run
  • Stick to the derived amount of fluid for longer runs
  • Drink at regular intervals of 15-20 minutes to keep up not more than 2% of the body’s water loss
  • A body weight loss of more than 2% will impair your performance
  • If you gain weight, it is a clear indication that you drank too much fluid

The crux of the process is to try and match your fluid intake with the fluid loss. Weighing yourself periodically before and after the run will give you a fair idea of the amount of fluids that need to be replaced.

Sports Drink Vs Water

Every fluid has a different absorption rate. Water is the most popular drink amongst athletes as it is absorbed most readily (hypotonic). It is followed by sports drink (isotonic) and fruit juice, which is the least absorbable (hypertonic) of all. Water quenches thirst and hydrates the body quickly, but does not replace the electrolytes lost due to sweat. It also does not provide any energy. Sports drinks contain water, electrolytes and carbohydrates. As they are isotonic, the good absorbability quickly replaces fluids lost during sweating and supply the required amount of energy for the run. One concern about sports drinks is that they contain extra calories. To balance that out, it would be wise to alternate between water and sports drink during the run.


Prachi Mandholia, M.S. , R.D. , is a registered Dietitian and a Certified Diabetes Educator. She is based out of Mumbai, India. She is a practicing Clinical Nutritionist and Columnist. Passionate about making changes in lifestyle. She is reachable at prachi.mandholia@gmail.com

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