International Journal of Exercise Science 9(5): 576-586, 2016. This study assessed 30 male and 20 female well-trained CrossFit (XF) athletes’ natural hydration statuses, fluid intake, and absolute and estimated sweat losses during training sessions lasting 30-47 min. Participants provided a pre-workout urine sample for assessment of hydration by urine specific gravity (USG). Nude pre- and post-workout body mass and fluid intakes were measured to determine sweat losses. To evaluate perception of total sweat loss, participants were asked to estimate their total sweat loss to compare against actual sweat loss. Mean sweat losses did not exceed 1% body mass for men (range = 0.31-1.58% body mass) or women (range = 0.53-1.34% body mass), but sweat rates were nearly double for men (1.663 ± 0.478 L/h) vs. women (0.886 ± 0.274 L/h). Pre-exercise USG indicated euhydration for the majority of participants (32/50 samples = USG < 1.020). Only one participant had a USG >1.030. Mean sweat loss (0.746 ± 0.305 L) and mean sweat loss prediction (0.655 ± 0.404 L) were not significantly different (p = 0.12), and accuracy did not differ (p = 0.44) between men (-9.5 ± 53.7%) and women (+4.3 ± 70.9). No relationship (r = 0.095) was found between sweat loss prediction and fluid intake. Despite high sweat rates, no athletes lost greater than 2% body mass during a strenuous workout. This data combined with consistently normal pre-exercise USG and high fluid intake during exercise suggests ad libitum fluid intake is sufficient to ensure euhydration in the majority of XF participants.
Cronin, Christina C.; O'Neal, Eric; Simpson, Jeffrey; Miller, Brandon L.; Green, Matt; Helm Allen, Jean A.; and Boman, Shelby
"Natural Training Hydration Status, Sweat Rates, and Perception of Sweat Losses During Crossfit Training,"
International Journal of Exercise Science: Vol. 9
Available at: http://digitalcommons.wku.edu/ijes/vol9/iss5/4