Effect of Hydration Status on High-Intensity Rowing Performance and Immune Function

Purpose: This study determined the effect of dehydration and rehydration (DR) on performance. immune cell response. and tympanic temperature idler high-intensity rowing exercise. Methods: Seven oarswomen completed two simulated 2000-m rowing race trials separated by 72 h in a random, cross-Over design. One trial was completed in a euhydrated (El condition and the other using a DR protocol. Results: The DR condition resulted in a 3.33 +/- 0.14% reduction in body mass (P<.05) over a 24-h period followed by a 2-h rehydration period immediately before the simulated rowing race. There was a greater change in tympanic temperature observed in the DR trial (P<.05). There were increases in the blood concentration of leukocytes. lymphocytes. lymphocyte subsets (CD3(+), CD3(+)/4(+), CD3(+)/8(+), CD3(-)/16(+), CD4(+)/25(+), P<.05) and decreases in lymphocyte proliferation and neutrophil oxidative burst activity immediately following the simulated race (P<.05) in both trials. Blood leukocyte and neutrophil concentrations were greater after exercise in the DR trial (P<.05). Whereas most immune measures returned to resting values after 60 mm of recovery in both trials, lymphocyte proliferation and the concentrations of CD3(+)/4(+) and CD4(+)/25(+) cells were significantly lower than before exercise. Blood leukocyte and neutrophil concentrations were significantly higher before and after exercise in the E trial. Conclusion: The effects of dehydration/rehydration did not negatively influence simulated 2000-m rowing race performance in lightweight oarswomen but did produce a higher tympanic temperature and had a differential effect on blood leukocyte. neutrophil, and natural killer (CD3(-)/16(+)) cell concentrations after exercise compared with the euhydrated state.