Home > Feature

How humidity affects your run

Any triathlete knows running in the heat is one thing, but running in high humidity is a whole other challenge. Around 60 per cent of the human body is made up of water. Release moisture up to skin level through sweating is how our systems cope with increased temperatures. When you go for a run in dry weather, the sweat you release evaporates into the air relatively quickly, so only a small amount of sweat is needed to keep cool. In humid conditions, there is so much moisture in the air it takes long for sweat to evaporate off skin. As a result, people sweat more in humid conditions while their bodies tries harder to cool down.

When you heat up too much, your circulatory system goes into survival mode, focusing on channeling blood flow to important organs at the expense of less critical ones such as the GI tract. This means it may be harder to absorb mid-run gels and sports drinks.

Generally, humidity becomes harder to deal with as you age. The body’s sweat reflex becomes less responsive. The larger an athlete is, the faster they heat up because of increased energy required to move their skeleton.

Breathing becomes shallower in humid conditions, which can lead to side cramps. While humidity is high, take it slower and focus on deep breaths. Extreme fatigue, nausea, headaches and dizziness are warning signs that heat stroke is approaching. If you begin experiencing any of these symptoms, it is time to abort the run.

Here are some tips if you’re heading out into the humidity:


1) Drink lots

This may seems simple. but you’d be surprised how many runners forget an extra glass pre-run on humid days.

2) Keep icy

Right before you head out the door, throw some ice cubes in your sports bra, shorts or hat, to keep your body cool for as long as possible.

3) Keep your water cool

Though it may be tempting to go nuts with the ice cubes, cool water, rather than cold, is faster absorbed by the body.

4) Wear light clothing

Loose-fitting gear allows for some airflow around the skin, keeping you cooler. Also opt for lighter colours. Black absorbs the sun’s rays, while light colours and white will reflect them.