Practical neck cooling and time-trial running performance in a hot environment.

Area of Science:

• Exercise Physiology
• Environmental Physiology
• Sports Science

Background:

• Heat stress significantly impairs exercise performance.
• Cervical (neck) cooling is a potential strategy to mitigate heat strain and enhance endurance.
• The effectiveness of neck cooling may depend on the duration and intensity of exercise in the heat.

Purpose of the Study:

• To investigate the impact of a cooling collar on time-trial (TT) performance in hot conditions (~30°C).
• To determine if a pre-load exercise phase influences the effectiveness of neck cooling.
• To examine physiological responses (rectal temperature, heart rate, RPE) and hormonal markers.

Main Methods:

• Two studies were conducted: Study A (75-min submaximal exercise + 15-min TT) and Study B (15-min TT).
• Participants completed TTs with a cooling collar (CC), without a collar (NC), or with an uncooled collar (C).
• Measurements included TT distance, rectal temperature, heart rate, RPE, and various blood hormone concentrations.

Main Results:

• In Study A, neck cooling significantly improved 15-min TT performance compared to uncooled or no collar conditions (P < 0.05).
• In Study B, 15-min TT performance was not significantly affected by the cooling collar (P = 0.351).
• The cooling collar did not alter rectal temperature, heart rate, RPE, or measured hormone levels in either study.

Conclusions:

• Neck cooling can enhance exercise performance in hot environments, particularly when preceded by a significant exercise bout.
• A threshold of thermal strain appears necessary to elicit a performance benefit from cervical cooling.
• The duration and potentially the intensity of exercise in heat are critical factors for the efficacy of neck cooling interventions.