Liquid Assets

What is 65-75% water? You are!  In terms of performance enhancing capacity, this means a lot. Water is perhaps the most underestimated nutrient when it comes to proven performance benefits. As little as a 3% loss in body water can cause a 6% reduction in speed! Translated to runner jargon, that could mean the difference of a sixty minute- 10km time or a 56:30 finish (when in fine hydrated form).

How do we become dehydrated? The human body loses fluids through sweating, breathing, and urination. The more miles you log, the more your water stores become depleted , and the less your body is able to sweat and regulate body temperature. Much like a low coolant level in a car - you risk overheating which could lead to heat illness if you don't drink enough fluids.

Sweat rates can vary from 0.5L/hour to 2.5L/hour. Environmental conditions, genetics, body size, fitness and exercise intensity all influence fluid balance. Every runner is unique in their fluid requirements and thus, determining your personal hydration needs is crucial for optimal health and performance.

Lavatory laboratory: Match fluid intake with sweat losses

Weigh yourself before and after a workout (before drinking, eating and urinating), and subtract the weight of any fluids ingested while exercising:

SWEAT RATE (Liters) = *weight before workout (in Kg) - *weight after workout (kg) + volume of fluids consumed (kg) (2 cups or 500ml = 0.5kg)

*To convert pounds to kilograms, multiply by 0.45

From field to practice: During runs strive to keep weight loss to less than 2% by drinking at a rate that is close to sweat rate. For every 0.5 kg of weight loss, drink 2-3 cups of fluid by taking small sips throughout your run. In most cases, plain water is fine for runs less than 1 hour. For longer runs, ingesting 20-60 grams of carbohydrate per hour and replacement of electrolytes may be needed.

Fluid overdose? Attention water guzzlers: more is not better! Over-occupying the port-a-potties is not the only implication of pounding back fluids. Of greater concern is that excessive drinking could pose serious health risks. Stick to drinking at a rate that matches sweat losses and hence limits body weight loss.

Whether seeking a spot on the podium, or running just for fun, avoid leaving yourself high and dry by ensuring your fluid needs are met for optimal performance, and possibly even a faster finishing time!