Last summer, I set out for a midday run, brimming with confidence, only to find myself dizzy and drenched in sweat just 20 minutes in, my body screaming for relief from the scorching heat.
It was a wake-up call—running in hot weather isn’t just uncomfortable; it can lead to dehydration, heat exhaustion, or even heat stroke if you’re not prepared. But don’t let the rising temperatures sideline your running routine!
With the right strategies, you can safely navigate the heat and maintain your performance on track. In this post, I’m sharing 15 expert-backed tips to help you run strong, stay cool, and avoid injury or heat-related risks, so you can enjoy every step, no matter how high the mercury climbs.
Dangers of Running in the Heat
Heat Cramps
When you run under the scorching heat of the sun, your body’s electrolyte storage suffers from imbalances or deficiencies due to sweating. This is what causes the sharp and stabbing muscle cramps, particularly in your legs.
Cramps are rarely able to work themselves out on their own. While cramps do become less frequent with regular training in the heat, for individuals not accustomed to extreme heat conditions, maintaining sufficient hydration and a proper balance of electrolytes can be challenging, making it difficult to avoid developing them.
To get rid of a cramp that pops up while you’re running in the heat, stop running, drink fluids that contain electrolytes, cool down your body as much as you can, and immediately find shade or somewhere inside to sit.
Severe dehydration
Dehydration is a common experience among those who exercise. A 4% fluid loss is considered safe, but anything more than that can make you feel dizzy, tired, and mentally disoriented.
Even if you are running in moderate heat conditions of 80 degrees, you can easily become progressively dehydrated. While you’re running, as your metabolic rate increases and your body produces a lot of heat on its own, your core temperature can increase to a dangerous level.
When you’re exercising in the heat, your body has to deal with the heat in the air and the heat that is being produced by your muscles. 80% of the energy that your muscles generate turns into heat.Â
If you are running in cold weather, that inefficiency keeps you warm. However, because your body has to get rid of this heat if you are running when it is hot outside, the heat from your muscles will make you even more uncomfortable because it will remain in your immediate atmosphere.
One of the body’s reactions to this is to send additional blood to the skin to help it cool down. However, this leaves your muscles with less oxygen-rich blood to use.Â
With less blood available to your muscles, which are working to make you run, your performance will be compromised. You will also start to sweat, which is your body’s way of getting rid of heat through evaporative cooling, which means your body is losing water, and you are progressively becoming more dehydrated.
To prevent dehydration, you have to ensure that you are well-hydrated before you go out for your run. To know if you are well hydrated or not, check and see if your urine is clear or has a light color. It is best to drink about a pint of water two hours before going for a run to help ensure your body is adequately hydrated and to give your body enough time to excrete any excess fluids.
Heat exhaustion
This is a combination of dehydration, severe headaches, vomiting, and high body temperature. Heat exhaustion is the result of excessive fluid loss and electrolyte imbalance without adequate replacement.
When suffering from heat exhaustion, you may experience weakness, goose bumps, and a lack of coordination. Your heart rate will likely increase, and because you feel fatigued, your running performance will be compromised. Even if you are well-trained in the heat, you may suffer from mild heat exhaustion after a long run in the sun.
If you are having symptoms of heat exhaustion, stop running and get out of the sun so your body can cool down. Drink fluids that contain electrolytes, and try to lie down with your feet elevated a few inches above your heart. Because heat exhaustion can quickly turn into heatstroke, it is essential to seek medical attention as soon as possible.
Heatstroke
This is an extreme case of heat exhaustion, where your core body temperature rises above 105 degrees Fahrenheit. Heatstroke is a severe, untreated form of heat exhaustion.
Heatstroke is a life-threatening situation that needs to be properly treated immediately. While untreated heat exhaustion can quickly progress to heatstroke, heatstroke often occurs without any warning. When having heatstroke, people often experience lethargy and muscle weakness, confusion and abnormal behavior, and may become unconscious.
Because heatstroke involves the body’s inability to regulate its temperature, sweating stops, causing the skin to become hot and dry. You may have convulsions or seizures as your brain starts to shut down, which may also lead to coma or death.Â
Heatstroke is considered a medical emergency that requires immediate attention. While waiting for emergency services to arrive, the person experiencing heatstroke needs to be removed from the sun and immersed in ice or cold water.
How to Run in the Heat
1. Head out earlier than usual.
Avoid running under the heat of midday, and instead head out during the early hours of the morning. Summer mornings have the lowest temperatures, since there is less ozone in the atmosphere during this time of year. The sun is the Earth’s only significant source of heat, so when the sun goes down at night, that source of heat is temporarily lost, and the air and ground start to cool down. The longer they are not exposed to the heat of the sun, the colder they get.
Because early morning is the longest time since the sun has warmed up the earth, this is the coolest time to go for a run, before the sun begins to heat up the atmosphere again. If you’re not much of a morning person, you can also run in the evening when the temperature is low.
Either way, check the temperature for the following day when planning to go for a run and see when the temperatures will be the coolest. Also, check the humidity levels, as this is an essential factor in staying cool. If you can only exercise in the middle of the day in the peak of the heat, consider doing a different exercise, such as swimming or running inside on a treadmill.
2. Consider trail running instead.
It’s nice to get off the road sometimes and immerse yourself in the beauty of nature. Trails are usually shaded, making your run a bit cooler. Additionally, roads are made out of concrete and asphalt that absorb heat and then radiate it back to your body.
Ensure you get some trail running shoes specifically designed for these conditions, and remember to bring enough water to stay hydrated. Staying out of direct sunlight while running on a trail can significantly reduce your risk of developing heat-related health conditions.
3. Adjust your routes and look for shaded roads.
If you don’t have enough time to do trail running, then just be wise in choosing the right routes and roads—those that are completely (or almost entirely) shaded. Plan out running routes for hot days when you are out driving around so you can pick out the roads that provide a sufficient amount of shade.
If you live near any type of water, such as rivers, lakes, and oceans, these bodies of water often create an environment with lower temperatures and breezier conditions. Another benefit of running near water is that you can take a dip to cool off after you’re finished.
4. Run and work out mildly and slowly.
Your body needs to adjust to the temperature, so don’t start your summer with intense and strenuous training activities. If you start with high-intensity running, your heart rate may skyrocket, which can lead to heat-related illnesses.
When you start running in the heat, your body will quickly adapt to the conditions in many ways. After your first few slow runs, the volume of your blood plasma begins to increase, giving your body more fluid to sweat to help cool you down while running. The increase in plasma also makes it easier for your body to send blood to your skin to help cool you down without reducing too much blood flow to your muscles.
Also, you begin to sweat earlier in your run as your body becomes accustomed to anticipating the rise in your core temperature. You also sweat more profusely, but your sweat contains less salt than usual because your body is trying to conserve sodium. Your heart rate slightly decreases at whatever level you are running, allowing it to fill between beats and pump out more blood. Not only does this blood fuel your muscles, but it also helps your body regulate its temperature.
When you increase your effort gradually, your perception of how much effort you are putting forth while running in hot weather changes. You only need to do one to two weeks of heat training to adapt your body to the conditions. Make sure to start gradually so you don’t overheat, just as if you were going to ease into running at a high altitude.
5. Get updated on the weather.
Get yourself updated about the weather on your planned running day. The National Weather Service updates its website every day, so you can check there to help you prepare.
This will help you determine which time of day is the coolest and least humid. It will allow you to check for possible storms in your area. Knowing what time is best to go out will also help you when planning to pre-hydrate.
6. Feel the breeze and be one with the wind.
Running with the wind and against it provides a cooling effect. When you start your run, go against the direction of the wind so you will feel much cooler. Once you head back home, run back with the tailwind.
Feeling the wind against your skin will keep you cool for two reasons. First, the temperature of your skin is typically higher than that of the air around you, so if you stay still or there is no wind, your body will warm the immediate surroundings. However, if you continue to move through air that is cooler than your skin before it begins to warm, you will constantly be moving into cooler air, allowing forced convection to keep you cool.
Another way that wind cools your skin is by helping your sweat evaporate. If you stay still and there is no wind, as you sweat, the air surrounding your skin becomes more humid, and the water molecules will eventually stop leaving your skin. However, when you are in the wind, it pushes the moist air away from your body and replaces it with drier air.
7. Make sure you’re hydrated before you start your run.
Drink enough water throughout the day to stay hydrated, but consider drinking more water if you plan to run for longer periods. This means you have to drink fluids before, during, and after your run. Your body’s need for fluids varies with several factors, including exertion and the climate, as well as humidity and temperature.
Drink before going out for a run in the heat, and ensure you have access to fluids during your run if you plan to be out for longer than 30 minutes. If you are going for a long run, some of your fluid intake should include a drink that contains electrolytes to replace any lost salt and minerals in your body.
8. Keep yourself hydrated while you run.
As previously mentioned, if you are going out for longer than 30 minutes, it’s not enough to hydrate yourself before you run. You must also stay hydrated while running, and there are a few ways to do this if you prefer not to carry water bottles with you.
First, plan your route around places that have water fountains, such as parks, schools, and gas stations. If you can’t do this, consider stashing water bottles along your route so you know where to pick them up—just make sure to pick them up and then dispose of them properly. Drink often to avoid becoming dehydrated.
9. Fill yourself up with vitamins and minerals.
The summer heat can mess up the number of vitamins and minerals your body can maintain. Thus, it is essential to supplement your diet with food rich in vitamins and minerals to replenish the ones you have lost. For example, sodium and potassium make up electrolytes, which become ionic conductors when they’re dissolved in fluids.
These minerals are beneficial because they help your cells send electrical impulses to each other. Because you lose electrolytes when you sweat during a hot run, it is important to fill your body up with them as soon as you can.
It is also important to supplement your body with magnesium. First, a magnesium deficiency can lead to increased sweating because it can cause anxiety. Also, because magnesium has a calming effect on your body, it can help you get a better night’s sleep to prepare you to take on the heat when you run.
Infographic: How To Run In The Heat: 15 Strategies To Survive In Hot Weather
Want to know how to run and survive in the heat? Check out this infographic below to learn how to withstand the scorching heat of the sun.
10. Don’t consume too much alcohol or medicine.
Chemicals in alcohol, antidepressants, antihistamines, and other substances can produce a dehydrating effect. As much as possible, avoid consuming too much of them to avoid the risk of dehydration.
Many medicines have a diuretic effect, meaning that they reduce the amount of fluid in your blood vessels. This is also one reason why alcohol is dehydrating to your body—it decreases your body’s production of anti-diuretic hormones, which your body needs to retain water.
Some other medications have a laxative effect, drawing water from the body to help move stool through the system. This prevents your body from retaining the water you drink, as it simply passes through your system. However, if you avoid alcohol and unnecessary medication, your body can retain its hydration much more effectively.
11. Use sun-protection skincare products and lotions.
Sunscreen will help you avoid absorbing the harmful rays from the sun. Check your sunscreen protection factor (SPF) to determine how long your sunscreen can protect your skin. There are different skin types, so make sure to choose wisely when choosing a sunscreen lotion.
Using a stick formulation for your face when you’re running is ideal because the sunscreen won’t run into your eyes as you begin to sweat. If you’re going to be out running for over two hours, you will need to remember to reapply your sunscreen during your run.
12. Wear the right outfit.
Wear as little clothing as possible. Clothes made from microfiber polyesters and cotton blends are best suited for the summer heat. Don’t do the layering technique if you’re running under the heat of a raging sun.
Also, ensure that your clothing is loose so you can feel the breeze underneath the material. It is great if you can wear a tank top and loose shorts while out for your run—just make sure that you are wearing enough sunscreen to protect your exposed skin.
13. Avoid wearing cotton or dark-colored shirts.
Choose shirts and shorts or pants that are not just lightweight, but also light in color. Dark colors absorb more heat. Light-colored clothing reflects the sun’s rays away from your body instead of absorbing them.
Ideally, loose-fitting, moisture-wicking fabrics are great for running in hot conditions. These will keep you dry as you start to sweat.
14. Learn to stop when you need to.
Once you start experiencing any of the previously mentioned symptoms from running in the heat, it’s time to stop and rest for a while. Look for a shaded place, and drink plenty of water.
It’s not worth pushing through hot conditions. If you run through these symptoms and become ill, you won’t be able to run for a while, so it will hurt your running routine. Listen to your body.
15. Feel the run, feel the moment.
This means that you should run by effort, and not by pace. Instead of following a strict timeline and trying to finish a certain distance at a given time, try to run with no pressure and just pure effort.
Running is something that you should enjoy doing. While it is great to push yourself while you’re running, you shouldn’t require yourself to run at a certain pace that makes you truly uncomfortable. Give your running your best effort, but don’t beat yourself up if you need to slow down.
Final Thoughts
Running in the heat can be both advantageous and disadvantageous. On the plus side, your body gets more efficient at cooling down your core temperature, and the process improves as you get used to it.
On the other hand, when the sweltering heat gets too dangerous, it becomes harder to exercise safely. As the temperature and humidity skyrocket, your electrolyte balance starts to disrupt, and it becomes more difficult for your body to cool down.
In this post, we’ve talked about the negative things that may happen if you run in the heat. We also gave you some tips on how you can avoid these dangers and survive the hot weather.
We hope that we were able to help you with this post. If you’re still a beginner and looking for a general guide on how to start your running routine, you might enjoy checking out this post.
Check out some more running tips:
- How to Run in Cold Weather: 10 Tips
- Exercises to Increase Your Lung Capacity
- Can You Run After a Leg Day Workout? (Our Answer)
- 8 Cardio Alternatives to Running When You’re Injured
- 7 Best Running Shirts for Hot Weather to Stay Cool (2025 Review)
- Which is Better for Your Knees: Running on a Treadmill or Outside?
