Acute effect of thermoregulation on cardiovascular drift during aerobic exercise–a case study

Abstract

This laboratory study investigates the effect of cardiovascular oscillations in thermoregulation during 45 minutes of aerobic exercise at a constant speed at room temperature between 24 and 25 °C with no fluid replacement. The research objective was to analyze the behavior of body temperature, heart rate, blood lactate and blood pressure, taking into account the water loss during the race at a constant intensity (approximately 70% of anaerobic threshold speed). Thus, we selected an individual physically active, practicing triatlhon long distance for over two years, with a weekly circulation of at least three times and no associated pathology. For the data collection were two test sessions on a treadmill (0% incline). In the first session, a maximum test was done with oxygen gas analyzer equipment, heart monitor and blood lactate analyzer. In the second session, physiological changes were observed during the race for 45 minutes at a constant rate (71.4% of anaerobic threshold speed). The results show that despite having been found a linear relationship between heart rate and oxygen consumption to a certain point, the prescription of training for athletes seeking to improve performance doesn ́t have to be based in heart rate only. We conclude that even at ambient temperatures appropriate, the water loss in endurance training causes the cardiovascular system to perform major adjustments in order to maintain cardiac output.