Thermoregulatory responses during competitive marathon running

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Sports Science

Background:

• Thermoregulation is critical for endurance athletes.
• Understanding heat balance during marathon running is essential for performance and safety.

Purpose of the Study:

• To investigate thermoregulatory responses in runners during a competitive marathon.
• To analyze core and skin temperature changes and their relation to heat balance.

Main Methods:

• Measured rectal (Tre) and skin temperatures in two runners during a marathon.
• Recorded race times and total body water loss.
• Utilized partitional calorimetry to estimate heat exchange.

Main Results:

• Rectal temperature plateaued early but showed a secondary rise in one runner.
• Runner 1 experienced a rapid Tre increase (40.9-41.9°C) between 113-119 min.
• Despite high Tre, runner 1 maintained pace and showed no signs of heat illness.

Conclusions:

• Thermoregulation remained intact in both runners despite significant thermal strain.
• Decreased sweating may have contributed to the rise in core temperature in one runner.
• Individual thermoregulatory capacity varies even under similar race conditions.