Cooling the neck region during exercise in the heat

Cooling the neck region can improve the ability to exercise in a hot environment. It might improve performance by dampening the perceived level of thermal strain, allowing individuals to override inhibitory signals.

To investigate whether the enhanced ability to exercise in a hot environment observed when cooling the neck region occurs because of dampening the perceived level of thermal strain experienced and the subsequent overriding of inhibitory signals.

Crossover study.

Walk-in environmental chamber.

Eight endurance-trained, nonacclimated men (age  =  26 ± 2 years, height  =  1.79 ± 0.04 m, mass  =  77.0 ± 6.2 kg, maximal oxygen uptake [V˙O(2max)]  =  56.2 ± 9.2 mL·kg(-1)·min(-1)) participated.

Participants completed 4 running tests at approximately 70% V˙O(2max) to volitional exhaustion: 2 familiarization trials followed by 2 experimental trials (cooling collar [CC] and no collar [NC]). Trials were separated by 7 days. Familiarization and NC trials were performed without a collar and used to assess the test variability.

Time to volitional exhaustion, heart rate, rectal temperature, neck skin temperature, rating of perceived exertion, thermal sensation, and feeling scale (pleasure/displeasure) were measured.

Time to volitional exhaustion was increased by 13.5% ± 3.8% (CC  =  43.15 ± 12.82 minutes, NC  =  38.20 ± 11.70 minutes; t(7)  =  9.923, P < .001) with the CC, which reduced mean neck skin temperature throughout the test (P < .001). Participants terminated exercise at identical levels of perceived exertion, thermal sensation, and feeling scale, but the CC enabled participants to tolerate higher rectal temperatures (CC  =  39.61°C ± 0.45°C, NC  =  39.18°C ± 0.7°C; t(7)  =  -3.217, P  =  .02) and heart rates (CC  =  181 ± 6 beats/min, NC  =  178 ± 9 beats/min; t(7)  =  -2.664, P  =  .03) at the point of termination.

Cooling the neck increased the time taken to reach volitional exhaustion by dampening the perceived levels of thermal strain.