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.