RESUMO
AIM: To assess the within-subject variation of thermoregulatory responses during 2 consecutive 15-km road races. Secondly, we explored whether gastrointestinal temperature (TGI) data from the first race could improve our previously established predictive model for finish TGI in the second race. METHODS: We measured TGI before and immediately after both races in 58 participants and determined correlation coefficients. Finish TGI in the second race was predicted using a linear regression analysis including age, BMI, pre-race fluid intake, TGI increase between baseline and the start of the race and finish TGI in the first race. RESULTS: Under cool conditions (WBGT 11-12°C), TGI was comparable between both races at baseline (37.6±0.4°C vs. 37.9±0.4°C; p=0.24) and finish (39.4±0.6°C vs. 39.4±0.6°C; p=0.83). Finish TGI correlated significantly between both races (r=0.50; p<0.001). The predictive model (p<0.001) could predict 32.2% of the finish TGI in the second race (vs. 17.1% without finish TGI in race 1). CONCLUSION: Our findings demonstrate that the use of previously obtained thermoregulatory responses results in higher predictability of finish core body temperatures in future races, enabling better risk assessment for those athletes that are most likely to benefit from preventive measures.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Corrida/fisiologia , Adulto , Feminino , Trato Gastrointestinal/fisiologia , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Modelos BiológicosRESUMO
Exercise-induced increase in core body temperature may lead to the development of hyperthermia (>40.0°C) and/or decreased performance levels. This study examined the effects of wearing a cooling vest during a 5-km time trial on thermoregulatory responses and performance. 10 male masters athletes (42±10 years) performed a 5-km time trial on a motorized treadmill in a climate chamber (25°C, 55% relative humidity) with and without a cooling vest. Split times, heart rate, core-, skin- and cooling vest temperature were measured every 500 m. Subjects also rated thermal comfort and level of perceived exertion. The cooling vest significantly decreased heart rate (p<0.05), decreased skin temperature (p<0.001) and improved thermal comfort (p<0.005) during the time trial. Time to finish the 5-km time trial and pacing strategy did not differ between the control (1 246±96 s) and cooling vest condition (1 254±98 s, p=0.85). Additionally, thermoregulatory responses, maximum core body temperature and level of perceived exertion were not different across conditions (p=0.85, p=0.49, p=0.11, respectively). In conclusion, we demonstrated that wearing a cooling vest during exercise improves thermal comfort but does not enhance performance or decrease core body temperature in male masters athletes under temperate ambient conditions.
Assuntos
Desempenho Atlético/fisiologia , Regulação da Temperatura Corporal/fisiologia , Vestuário , Exercício Físico/fisiologia , Adulto , Estudos Cross-Over , Frequência Cardíaca , Humanos , Ácido Láctico/sangue , Masculino , Pessoa de Meia-Idade , Temperatura Cutânea , TemperaturaRESUMO
BACKGROUND: Prolonged, moderate-intensity exercise training is routinely prescribed to subjects with obesity. In the general population, this type of exercise can lead to fluid and sodium imbalance. However, little is known whether obesity alters the risk of fluid and sodium imbalances. OBJECTIVE: This study examined physiological responses, such as core body temperature, fluid and sodium balance, in lean (BMI<25), overweight (25