NUTRITION
A new study underlines the importance of being hydrated before a race or workout
IN THE HOURS before a key running session, many thoughts fill the runner’s head. ‘Why am I doing this?’ ‘Is it a bit nippy for a vest?
‘Should I take a gel?’ But the question of whether you’ve drunk enough water often falls off the list – and the consequences are significant.
A recent study* had participants complete 72 minutes of running on a treadmill. One group of runners were given so little fluid during this time that they lost 2.2% of their body weight.
The other group received enough fluid so that they lost only 0.5% of their body weight.
Then both groups were asked to complete a 3000m time trial (also on a treadmill).
The result? The dehydrated subjects were significantly slower – an average of 55 seconds, which amounted to a 6% difference. This led the researchers to conclude that, ‘Exerciseinduced hypohydration [the uncompensated loss of body water] of approximately 2% body mass impaired 3km running time-trial performance.’ This, they thought, was likely due to ‘increased cardiovascular strain (indicated by increased heart rate and decreased plasma volume) and thermal strain, which altered the perception of effort’. What’s interesting is the temperature inside the laboratory was only ‘temperate’; had the temperature been hotter, the decline in performance might have been greater still. So, make sure you’re fully hydrated before your next race or key session – and drink in the benefits.
