During
performance
During
performance nutrition needs to be focused on maintaining energy levels.
Endurance events and events in hot and humid conditions can have a significant
impact on the body's fuel and fluid supplies. The need for carbohydrate and electrolyte 
replacement depends on a number
of factors including intensity, duration, humidity, and individual sweat rates.
In the case
of moderate to high-intensity activities lasting longer than 60 minutes
(including individual or team-based sports of an intermittent nature)
additional fuel in the form of carbohydrate supplementation is needed to avoid
glycogen depletion. Appropriate liquid carbohydrate supplements (e.g. some
sports drinks) can delay glycogen depletion by up to 30 minutes at exercise
intensities above 75% of aerobic capacity. Liquid carbohydrate is not necessary
for low intensity, short-duration exercise. Sports gels and bars are being used
more increasingly by athletes as these are easy to consume and digest quickly
providing a quick release of energy for the athlete as well as reduce the risk
of gastrointestinal problems. Care should be taken that these products are well
researched and used appropriately.
Adequate
hydration by regular fluid intake must be maintained and needs to the body's
requirements and the exercise duration and intensity. 200-300 mL of fluid is
recommended to be consumes every 15-20 minutes during exercise. An athlete
should not use thirst as an indicator of dehydration as hydration levels may be
well depleted by that time and performance may already be affected. Dehydration
of even 2% can have a detrimental effect on an athlete's performance.
For further
reading on nutritional considerations during performance can be found on the
following websites:
- Sports Dietitians Australia -
Eating and drinking during and after sport.
- Australian Institute of Sport - Factsheets: Fluid - who
needs it.
- Australian Institute of Sport - Factsheets: How much do
athletes sweat?