Hydration status, sodium loss, and fluid intake during cycling and skating training.

Abstract

Introduction: Acute dehydration is not something to be
ignored, since it affects cognitive function and concentration,
especially when the athlete is exposed to hot environments,
at which time, by the way, the perception of exertion increases. Therefore, one way to prevent this type of dehydration is to measure the athlete’s hydration status and determine individual fluid needs.
Objective: Determine hydration status, sodium loss and fluid intake during cycling and rollerblading training.
Methods: The hydration profile of 75 athletes of both
sexes, 35 belonging to speed skating and 40 to elite level
track cycling, was evaluated. The hydration status was estimated for each one before training through urine specific
gravity (USG) with an ATAGO Pal10-S digital refractometer.
Similarly, sweat sodium concentration was determined during
the training session, using a LAQUAtwin-Na-11HORIBA
portable sodium meter. Finally, sweat rate was calculated
from differences in body weight, fluid, and food intake. The
tests were performed by sport at different times of the day,
with a duration of 1,9 ± 0,2 hours of training.
Results: It was observed that 28% of athletes start with
dehydration greater than 1,026 and it increases after training,
with a loss of body weight between 1,0 and 1,2%, showing a
significance level of 0,01 between weight, before and after
training. Regarding the sweating rate, it was between high
and very high, being higher in cyclists (with 77,5%) and in
skaters (with 54%). It should be added that the cyclists had
a sodium loss of 2 ± 1,2g higher than that of the skaters who
was 1,8 ± 1g. In terms of gender differences, men had a
higher sweat rate and greater sodium loss.
Conclusions: These results show that the greater the loss of
sodium, the greater the rate of sweating in athletes. In addition,
the findings of this study confirm the need to cover water requirements in training through drinks that provide sodium.