A Comparison of 2 Practical Cooling Methods on Cycling Capacity in the Heat.

Context: Cooling the torso and neck can improve exercise performance and capacity in a hot environment; however, the proposed mechanisms for the improvements often differ.

Objective: To directly compare the effects of cooling the neck and torso region using commercially available devices on exercise capacity in a hot environment (temperature = 35°C ± 0.1°C, relative humidity = 50.1% ± 0.7%).

Design: Crossover study.

Setting: Laboratory.

Patients Or Other Participants: Eight recreationally active, nonheat-acclimated men (age = 24 ± 4 years, height = 1.82 ± 0.10 m, mass = 80.3 ± 9.7 kg, maximal power output = 240 ± 25 W).

Intervention(s): Three cycling capacity tests at 60% maximal power output to volitional exhaustion: 1 with no cooling (NC), 1 with vest cooling (VC), and 1 with a neck cooling collar (CC).

Main Outcome Measure(s): Time to volitional exhaustion, rectal temperature, mean skin temperature, torso and neck skin temperature, body mass, heart rate, rating of perceived exertion, thermal sensation, and feeling scale were measured.

Results: Participants cycled longer with VC (32.2 ± 9.5 minutes) than NC (27. 6 ± 7.6 minutes; P = .03; d = 0.54) or CC (30.0 ± 8.8 minutes; P = .02; d = 0.24). We observed no difference between NC and CC (P = .12; d = 0.31). Neck and torso temperature and perceived thermal sensation were reduced with the use of cooling modalities (P < .001), but no other variables were affected.

Conclusions: Cycling capacity in the heat improved when participants used a commercially available cooling vest, but we observed no benefit from wearing a commercially available CC. The vest and the collar did not alter the heart rate, rectal temperature, skin temperature, or sweat-loss responses to the cycling bout.