| Summary: | Background: Competitive rowers among other athletes, compete in relatively cold environmental conditions. A warm-up is a standard procedure in all sports, and athletes complete it in order to increase body metabolism and tissues. Delays that occur before races can force rowers to be constrained to their boat and lose the effects of the warm-up. Quick racing starts following long delays do not allow time for additional warm-up; therefore, performance during the race may be affected, which is important since rowers perform supramaximally for about 6 to 8 minutes. This combination of intensity and duration does not give the body enough time to benefit from gradual warm-up effects that occur during the first few minutes of exercise at a lower intensity. Purpose: The purpose of this study is to examine the effects of varied durations of post warm-up periods on the metabolic, thermoregulatory, and performance responses during subsequent high intensity rowing or running in a cold environment. Method: Five experienced rowers (1 female; 4 male) and five trained runners (2 female; 3 male) completed four trials consisting of a standardized warm-up followed by: 5 minutes of rest in room temperature (5-R); 5 minutes of rest in the cold (5°C) (5-C); 30 minutes of rest in room temperature (30-R); 30 minutes of rest in the cold (30-C). After the resting period, rowers performed a 2000 meter time trial on a rowing ergometer and runners performed a 1.5 mile time trial on a treadmill. Blood samples were collected pre-exercise, post-warm-up, pre- and post-time trial and 3 minutes post-time trial and were analyzed for lactate concentration in all participants, and pH and bicarbonate (HCO3-) in the rowers. Core temperature (Tc) was measured via an esophageal probe, skin temperature (Tsk) was measured via surface probes on four sites of the body, and heart rate (HR) was measured via a Polar monitor. These variables were measured every five minutes during the warm-up and resting period, and every quarter of the time trial. Results: In performance times, there were no interactions found between conditions; however, there was a tendency for slowest times to be completed in 30-C and the fastest times in 5-R. Statistical analysis could not be performed for pH and bicarbonate responses due to the lack of complete data. These variables both returned to pre-exercise values after 30 minutes of rest and the smallest changes after the time trial occurred in 5-R. No significant interactions were found in blood lactate concentrations; however, there were increased rates of clearance following 30 minutes of rest, smaller changes after the time trial in 5-R, and slightly lower concentrations in the cold trials. A significant rest time by environment by time point interaction was found for Tc (p=0.00). At the end of rest, average Tc was significantly greater in 5-C and during performance, peak Tc was significantly lowest in 30-C, both compared to all other trials. A similar interaction was found in Tsk (p=0.00) and during warm-up, Tsk significantly decreased in cold trials compared to room temperature. Also, at the end of rest, Tsk was significantly lower in 30-C compared to the rest of the trials and remained lower throughout the time trial. HR was significantly lower after performance in 30-C compared to all other trials (p < .05). Summary: We found significantly colder core and skin temperatures during the trials in the cold and significant differences in variables when comparing 30 minutes of rest to 5 minutes. Even though performance was not significantly slower in 30-C, it would seem that there was a combination of physiological events due to temperature and prolonged rest time that may have affected performance. From the results, we can conclude that performing an adequate warm-up and maintaining core temperature, especially in the cold, is important for preparation before a high-intensity bout of exercise, and that athletes should consider this information when performing in colder environments.
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