Running in humidity is dreaded by just about every runner. For runners who live in a mild climate, humidity can take them by surprise when traveling. Runners who live in tropical climates or areas with changing seasons often despise running in the thick of summer.
Heat and humidity pose difficult conditions for runners of all ability levels. Running in high humidity can make a moderate or warm day feel absolutely miserable.
Why is it harder to run in humidity?
Humidity can be deceiving. Cool temperatures with high humidity can still make running feel difficult, and it often takes runners by surprise. Hot weather with high humidity is nearly impossible to navigate. So why is it so hard to run in humidity?
Ultimately, the higher the percentage of humidity, the more saturated the air is relative to the temperature. With more moisture in the air, it’s harder for sweat to evaporate. Breathing while running in humidity can also feel more difficult, as you’re taking in more moisture with the air.
Running in high humidity means that the body has to work harder to cool down. On days with high heat and humidity, heart rate can be anywhere from 10 – 30 bpm higher with the same level of exertion.
What is humidity?
In order to gauge how running in humidity can affect performance and training, it’s helpful to fully understand how humidity is measured.
Humidity refers to the amount of moisture in the air. In most weather apps and forecasts, humidity is recorded as a percentage. The percentage of humidity measures how saturated the air is with moisture.
The difficulty with humidity is that the measurement is relative to the temperature – the higher the temperature, the more moisture the air can hold. When the measurement is not absolute, it is difficult to compare. 90% humidity will feel entirely different in 50 degree temperatures as compared to 80 degrees.
Does running in humidity make it harder to breathe?
In many cases, running in high humidity can make it feel like it’s difficult to breathe. Some runners describe the feeling as trying to run through water, while others just struggle to catch the breath or settle into a rhythm throughout their run.
The reason it might feel more difficult to breathe in high temperatures with high percentages of humidity is because the air is more saturated with water. With each breath, you take in more water and less oxygen than on days with low humidity.
Will humidity slow down running pace?
Running in humidity may or may not slow down your pace, depending on a variety of factors. The biggest contributing factors are the percentage of humidity and the actual temperature. Conditions are considered “ideal” when humidity is between 30-50%. When humidity creeps above 50%, running might begin to suffer.
Humidity above 70% is sure to slow most runners down. According to Runner’s World, the average decrease is pace is about 30 – 90 seconds per mile when running in high humidity.
Runners who have already acclimated to a humid climate will find it easier to sustain their typical pace, whereas traveling runners who are thrown into humid conditions for a single run or few days will likely experience a decline in performance.
10 Tips for Running in Humidity
Running in humidity is not always a sentence to a miserable run. There are a few steps runners can take to proactively prepare for humid conditions and make their runs more enjoyable. In addition, suffering through high humidity for a few weeks or months will likely help your performance improve once it disappears.
Run early – beat the heat
The best way to navigate running in humidity during the hottest months of the year is to run early. The earlier you get started, the cooler the temperature will be.
Not only will cooler temperatures make it easier to manage humidity, but the percentage of water the air can absorb will be lower, and the sun won’t be nearly as intense.
Reduce your intensity
Accepting the fact that running in humid conditions is going to affect your performance will help make the necessary adjustments during training.
Rather than pushing yourself to the point of exhaustion, reduce your intensity to make running more comfortable. Remind yourself that the continued effort in humid conditions will pay off when the weather changes in the fall.
Wear appropriate gear
Since running in humidity makes it harder for sweat to evaporate, it’s important to dress appropriately. Dressing in light clothing that is loose fitting will give your skin extra room to breathe when it needs it most.
Aim for shorts and tank tops, or as minimal as you feel comfortable dressing, to keep your skin exposed in the air.
Try a visor instead of a hat
Speaking of giving your body room to breathe, an easy switch to make when it’s humid is to wear a visor instead of a hat. Hats keep air trapped at the top of your head, and dark colors can absorb heat from the sun.
Opting for a visor instead of a hat will provide protection from the sun on your face, without creating extra heat on your head.
Take time to acclimatize
The best way to navigate running in heat and humidity for a long duration of time is to acclimatize to the conditions. Giving your body plenty of opportunities to get outside in the conditions when resting or giving minimal effort will help it adjust and prepare for the harder effort of running.
Hydrate with cool water
It might sound counterintuitive – taking in more water when your body is unable to release much sweat – but staying hydrated is essential when it’s humid.
A simple way to help stay cool is to make sure your water is as cold as possible each time you go to take a drink. Try adding ice or freezing half of it to take on your run.
Take breaks when needed
Trusting your progress and listening to your body is key to maintaining peace of mind when running in humidity. Remember that the same amount of effort when it’s humid might result in a slower pace, but is still building the same amount of fitness.
If you’re struggling during a humid run, allow yourself to take a break. Stop completely or slow to a walk to give your body time to recover. It’s important to take breaks as needed to avoid any serious issues or complications from the heat.
Plan a route through shade
High humidity doesn’t always mean that it’s hot and sunny, but any extra heat can really increase the difficulty during a run.
Take the time to plan a route ahead of time that will take you through as many shaded areas as possible to ensure you avoid any extra exposure to the elements – which might make things even more miserable on the run.
Check the heat index
Being prepared is key to successfully navigating running in humidity. Checking the weather conditions ahead of time will allow you to make any adjustments to gear, route or timing.
Be sure check the heat index and ‘real feel’ temperatures as opposed to the actual temperature. These indexes are adjusted based on all of the conditions and will give you a more accurate representation of what to expect during your run.
Listen to your body
Above all, listening to your body is key when it’s humid. If you’re struggling to keep going, don’t ignore it. Educate yourself about the signs of heat stroke and any other conditions that could result from high heat and humidity.
Don’t be afraid to take it easy if necessary. Powering through humidity is not always the best choice – listen to your body and give it the space it needs.
Benefits of Humidity and Running
It might seem like there is no good that will come from running in humidity. However, enduring tough conditions almost always result in improved performance later on.
Here are some benefits that come from humidity and running – important reminders to keep in mind when things are starting to feel miserable and endless on the hottest days.
- Improved efficiency when the weather cools
- Build mental strength
- More physiological adaptions can occur
- Smaller runners have an advantage in humidity – optimal for those who want to race
Dangers of Running in High Humidity
Running in humidity is certainly not always enjoyable, but it’s important not to get so caught up in the fact that it always feels miserable that you miss a warning sign for something more serious.
In most cases, it is still safe to run in humid conditions. However, runners need to be aware of the warning signs that might indicate the beginning of a serious condition. Here are a few of which you’ll want to know.
- Overheating – goose bumps, feeling faint, dizzy or fatigued
- Heatstroke – hot skin, confusion, exhaustion, high body temperature
- Heat cramps – excess sweating, muscle spasms or twitches
- Heat exhaustion – confusion, weakness, headache, nausea
- Dehydration – lack of urination, thirst, light headedness, fatigue, dry skin
Some other less serious conditions that might result from pushing your body too hard in high humidity or heat are feeling nauseated, experiencing shallow breathing or even side stitches.
Much like running through any other adverse condition, education, preparation and adjustment are key to success. Running in humidity will likely require a few adjustments, but when done ahead of time, many runners find that they can successfully run through humid conditions – and still enjoy it.
Hot and humid conditions provide a great opportunity to run by feel and simply get outside for enjoyment. Powering through these tough conditions now will set you up for even bigger success in the future.