Lower core temperatures reduce the burden on the cardiovascular system. This is because as body temperature rises, more blood is directed to the skin for cooling, which increases heart rate. By maintaining a cooler core temperature, the body can maintain a steadier cardiac output and reduce the compensatory increase in heart rate. (*63), (*64)
There are several scientific studies that explain the benefits of a lower heart rate for endurance athletes:
- A lower heart rate during exercise allows endurance athletes to operate within their aerobic thresholds longer, delaying the buildup of lactate. This adaptation, helps reduce muscle fatigue and extends time to exhaustion. In addition a lower exercise heart rate helps manage physiological stress over prolonged periods, which plays a role in delaying central and peripheral fatigue, both critical factors in endurance. (*46), (*47)
- With lower heart rates during exercise and faster post-exercise heart rate recovery, trained endurance athletes are better able to perform multiple sessions at high intensity. (*48)
- When endurance athletes can maintain a lower heart rate, they can sustain higher intensities for longer periods. At a given intensity this reduces cardiovascular strain and maximizes the time they can perform near their VO₂ max. (*49)
These studies collectively illustrate how endurance athletes benefit from a lower heart rate by delaying lactate buildup, manage stress better, recover faster and sustain performing near VO₂ max longer.
In conclusion: it is beneficial to keep core temperature lower DURING sports in order to keep the heart rate lower.