Effect of Humidity on Athletic Performance

It's pre-monsoon and soon it'll be monsoon season in India, and in places such as Delhi in Northern India, the high temperatures (soaring above 40 degrees C) coupled with high humidity makes for a bizarre situation for runners and cyclists since the air quality is far better than winters and therefore you'd want to be outdoors more, but the climatic conditions for prolonged or HIIT exercise are totally non-supportive.

During the season, as the humidity arrives and progressively increases, there is a general phenomenon amongst runners and cyclists to reduce the intensity and/or duration of exercise since the weather (high humidity in particular) feels awful and, quite visibly, exercise attire gets drenched in sweat in a matter of minutes, due to lack of evaporation. 

When such feelings arrive, there is a common psychological tendency to reduce the duration and/or intensity of exercise since athletes become hyper-focused on the palpable humidity and their sweat drenched clothes, and blame the high humidity for their lack of performance, like blaming god for getting fired from a job.

On an average day, I reach home from work at a little before 10 p.m., so I usually end up running in the mornings at about 7-8:30 a.m. when both heat and humidity are high and I also regularly get the feelings to take it easy during workouts, but I usually (unless I'm hungover) do not take it easy.

Enjoy the customary random photo since I'm not narcissistic enough to put mine

So the moot question is, 'how much does humidity affect athletic performance?' I'll ignore heat since there is ample and cogent evidence on the interwebz which demonstrates that increases in environmental heat (other than during warm-ups) after a certain point is directly related to decreases in exercise performance. Hence, allow me to ignore heat as a factor in relation to exercise performance since I don't want to bore you or misuse my blog like a conman for spewing information which is common knowledge or which is already available with a single Google search click.

Effects of heat and different humidity levels on aerobic and anaerobic exercise performance in athletes (https://www.sciencedirect.com/science/article/pii/S1728869X13000087) is one of the first studies which was conducted in the year 2013 to systematically investigate the effects of a hot environment and different humidity levels on VO2max and Wingate anaerobic test performance in the laboratory.

As per the aforesaid study, the VO2max performance was impaired in the hot–dry (i.e. hot and low humidity) and the hot–wet (i.e. hot and high humidity) conditions in comparison to the optimal temperature-optimal humidity (control conditions/thermoneutral conditions), but there was no difference between the hot–dry condition and the hot–wet condition. The researchers found that humidity changes did not further affect VO2max. This means that you should not decrease the intensity and/or duration of your non-HIIT (i.e. long runs/tempo runs/steady runs/recovery runs workouts) if you feel that the humidity is high and your clothes (and maybe shoes too like it happens to me in this season) are drenched in sweat. It's not the humidity, it's just your brain playing tricks. You reverse-trick that fucker and complete your workout, drenched or not.

In addition, it was found in the aforesaid study that anaerobic performance using the Wingate test (i.e. peak power and anaerobic capacity) was not affected by the hot–dry conditions or the hot–wet condition, compared to the control environment (thermoneutral conditions).

Lastly, the study was conducted during the spring season to avoid any natural heat acclimatization from the summer in the test subjects. Therefore, if you reside and run in a hot and humid environment, then to a certain extent your body has already acclimatized to the then existing environmental conditions.

This means that you can keep doing your shorter intervals (like really short intervals since Wingate HIIT tests are such) without being affected by heat or humidity, especially considering that your body may have acclimatized to a certain extent. Again ignore the monkey brain which is making your take extra notice of the humidity and drenched clothes.

In conclusion:

1. Humidity will not decrease your VO2max, but heat will. So don't blame the humidity and hammer through your workouts in the high humidity season; and
2. Short interval training/short HIIT will not be affected by heat or humidity, so hammer through those too!

In the next blog, I'll tell you about boosting metabolism through heat training. 

Make gains in this weather and be outside more, because Delhi's polluted winters are coming soon. Cough cough! Ouch.

- Aman Yadav