Precompetition weight loss and changes in vascular fluid volume in NCAA Division I college wrestlers

This study examined the effect of pattern of weight loss on plasma volume in NCAA Div. I college wrestlers preparing for a tournament. Twelve subjects lost an average of 6% body weight (BW) by thermal and exercise-induced dehydration, but at varying rates during the week of the experiment. After 15 hrs of rehydration, BW was still below baseline, indicating that the wrestlers did not replace all BW loss during the night after a weigh-in. Subjects were grouped into gradual (G), moderate (M), and rapid (R) weight loss patterns by their change in BW from Days 1 to 6. G, M, and R had -1.77, -0.54, and 1.05% Δ in BW, respectively. There was a significant (p ≤ 0.05) correlation between pattern of weight loss and total %Δ BW, with G incurring greater loss in BW. Status of vascular fluid was assessed by measuring blood volume (BV), plasma volume (PV), red cell volume, osmolality, and total protein concentration ([TP]). Weight loss had no effect on precompetition osmolality or [TP], but significantly reduced pre-weigh-in BV and PV for all 3 groups. All 3 groups had a similar reduction in PV (∼400-500 ml; 11%) following dehydration. Differing weight loss patterns compromise PV equally; thus the rate of weight reduction the week prior to weigh-in has little effect on an elite college wrestler's BV and PV. Yet the negative effects of weight loss practices remain.