A study by Zhao et al. in 2013 explored the effects of three different environmental conditions on aerobic and anaerobic performance. There were nine Chinese, male, trained track and field athletes, with the average age of 21.6 ± 1.2 years and similar anthropometrics. The study was in the spring to prevent any natural heat acclimatization that would skew the results of the testing. Before testing there was one week of training to familiarize the athletes with the study’s protocols. After, the VO₂ max test and anaerobic Wingate test were performed by the athletes in in an environmental chamber under three different conditions. The conditions were—21 °C/20% R.H. (control), 33 °C/20% R.H. (hot–dry), 33 °C/80% R.H. (hot–wet).
The measured factors in each environment were, core temperature, skin temperature, RPE, venous blood samples, and exercise time. Oral temperature was taken with a thermometer to obtain core temperature after warm up and after completion of the tests. Thermocouples were placed on different sites of the body to measure skin temperature continuously throughout the testing.
It was hypothesized that VO₂ max would be hindered in both hot-dry and hot-wet environments more than in the control, and the hot-wet conditions would be the most detrimental to VO₂ max out of them all. Furthermore the Wingate anaerobic test was expected to not be affected by either change in heat or humidity.
VO₂ Max Results: Table 1
| Control | Hot–dry condition | Hot–wet condition | |
| VO2max (mL min−1) | 3779.0 ± 234.3 | 3528.2 ± 467.4* | 3595.9 ± 274.6* |
| VO2max (mL kg−1 min−1) | 54.3 ± 5.4 | 50.1 ± 7.2* | 50.8 ± 4.3* |
| Exercise time (min) | 12.62 ± 1.68 | 11.12 ± 1.39* | 10.79 ± 0.91* |
| HRmax (bpm) | 195.7 ± 10.7 | 197.5 ± 6.9 | 200.7 ± 15.5 |
| RPEmax | 15.7 ± 2.1 | 16.8 ± 1.7* | 17.4 ± 1.7** |
| Oral-to-skin temperature gradient (°C) | 2.2 ± 0.5 | 1.8 ± 0.7* | 1.6 ± 1.0* |
Conclusively, study showed that both hot-dry and hot-wet conditions hindered VO₂ max, with very little difference between each other (p > 0.05), in comparison to the control group. RPE was also affected, going up, almost equally in both hot-dry and hot-wet conditions. Furthermore, the extra humid conditions in the hot-wet environment did not seem to elicit more detrimental results than the hot-dry. Also the oral to skin temperature gradient and the exercise times were lower in both hot-dry and hot-wet conditions than in the control. Lastly, as expected, the anaerobic Wingate test was not significantly different under either of the hot conditions.
Source: Zhao J, Lorenzo S, An N, Feng W, Lai L, Cui S. Effects of heat and different humidity levels on aerobic and anaerobic exercise performance in athletes. Journal of Exercise Science & Fitness. 2013; 11(1):35-42.
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