how much do you really lose during a workout?

the TP performed below expectation for their IVP (inter varisty poly) race in late march due to dehydration. everyone complained that it was way too hot during the run.

heat and humidity is a very real problem in our climate. the langkawi ironman race that was completed recently seen more than 25% dropout, which is very high for an ironman race as most of the athletes came very prepared and most of them are suckers for pain. even they admit defeat in the face of 39 degrees heat and almost 100% humidity.

for the team who race under 1 hour, dehydration is not such a big problem yet as the chances of them getting heat stroke and other heat related conditions are low. but their performance can be severely compromised.
a loss of 3% of body weight can impaired performance of up to 10%.

as a test and preparation for the april national school events that will be held at 2pm, we conducted a almost mid day workout to monitor the amount of water lose and plan hydration and nutrition strategy accordingly.

in teh 5km or 30min run on the track at 11am, all the athletes lose 500g to 4kg of body weight. all the athletes go to toilet before they weigh themselves in the gym, and fill up their water bottle with knowledge of how much they drink during the run. after the run, they did not change out of their wet sweaty clothing (that may account for the little difference in the body as we did not account for the the heavier soiled gear we are in) and weigh themselves again on the same scale.

the difference in weight + water consumed = total water loss

some of the athlets lose only 500g or less, some lose 4kg but most lost more than 2% of body weight. taking into consideration that this test only account for 30mins of heavy workout and some may not workout as hard, the loss in 1 hour would be around 2 times or more what we witness.

all of us are individual and our body respond differently but one thing for sure, all of us drink way too little before, during or after. and we dont replenish enough electroyles or suitable carolies for our training and racing needs.

do you know how much you hydration and nutrition you actually need?