Running in Hot Weather

If you enjoy running then you’ll always have to contend with a variety of weather, and one that can be the most challenging to run in, for both seasoned and novice runners is hot weather.

What happens to your body in the heat?

When running in the heat, your body undergoes several physiological changes to regulate its temperature and cope with the increased demand. Here’s what happens to your body when you run in hot weather:

  1. Increased sweat production: Your body produces sweat to cool down. As the ambient temperature rises, your sweat glands become more active, leading to increased perspiration.
  2. Elevated heart rate: Running in the heat places additional stress on your cardiovascular system. Your heart rate rises to pump more blood to the skin’s surface for cooling, as well as to the working muscles.
  3. Dehydration risk: Sweating leads to fluid loss, which can quickly deplete your body’s water and electrolyte levels. Dehydration can impair performance, reduce endurance, and even pose a risk to your health.
  4. Decreased blood volume: Sweating causes a loss of plasma volume in the blood, reducing the overall blood volume. This can affect the delivery of oxygen and nutrients to your muscles, making your run feel more challenging.
  5. Increased core body temperature: Running generates heat, and in hot conditions, your core body temperature can rise significantly. Your body tries to dissipate this heat through sweating and increased blood flow to the skin’s surface.
  6. Risk of heat-related illnesses: Running in the heat increases the risk of heat-related illnesses such as heat cramps, heat exhaustion, and heatstroke. These conditions can occur when your body’s cooling mechanisms are overwhelmed, and you fail to adequately replace fluids and electrolytes.
  7. Decreased performance: The combination of increased heart rate, dehydration, and elevated core body temperature can lead to decreased performance. You may feel fatigued, experience reduced endurance, and struggle to maintain your usual pace.
  8. Increased perceived effort: Running in hot weather can feel more challenging due to the physiological stress placed on your body. The perception of effort may be higher, even at slower speeds or shorter distances.

Due to all these reasons it’s important to take precautions and adapt your routine to ensure a safe and enjoyable experience.

Time your runs wisely

Plan your runs during cooler parts of the day, such as early mornings or evenings, to avoid the highest temperatures and reduce the risks of heatstroke etc.


Drink plenty of water before, during, and after your run to prevent dehydration. It’s that simple. You will sweat and get dehydrated on a hot run, so do all you can to limit the effect it has on your body.

Plan your route

When running in the heat, choosing the right running surface can make a difference in your comfort level and overall experience.

Running in the shade can take a few degrees off the temperature.
Running in the shade can take a few degrees off the temperature.

Here are some of the best running surfaces to consider:

  • Shaded Trails: Running on shaded trails or paths with ample tree cover can provide relief from direct sun exposure. The shade helps to lower the ambient temperature, making your run more comfortable.
  • Grassy Parks: Grass surfaces have natural cooling properties as they absorb less heat compared to asphalt or concrete. Running on grass can provide a softer impact on your joints and offer a cooler surface to run on.
  • Dirt or Gravel Trails: Running on dirt or gravel trails can be beneficial in hot weather. These surfaces tend to retain less heat than tarmac or concrete, providing a cooler running experience. They also tend to be more forgiving on your joints.
  • Coastal or River Paths: Running near bodies of water, such as coastal paths or lakeside trails, can offer a refreshing breeze and a cooler microclimate. The presence of water helps to moderate the temperature, making it more pleasant for running.
  • Urban Areas with Tall Buildings: In urban environments, running along streets with tall buildings can provide some shade and block direct sunlight for portions of your run. However, be mindful of increased heat trapped between buildings.
  • Indoor Running: When the heat is particularly intense, consider running indoors on a treadmill or using indoor tracks. These controlled environments offer air-conditioned or climate-controlled settings, ensuring a more comfortable and safer running experience.

Ultimately, the best running surface in the heat will depend on your location, personal preferences, and availability of different options

Running on tarmac
You can feel the heat coming off the tarmac and there is zero shade on this run of mine.

Reduce your distances and pace

In the heat you will struggle to maintain your usual pace due to the increased exertion on your body so accept that you will not be able to run the distances you would like and that your pace will be slower too.

This doesn’t mean you have to drastically cut your runs, but just be aware that knocking a few km off your total distance isn’t a bad thing and will help your recovery so you can fight enough day.

Wear sunscreen

Wearing sunscreen when running in hot weather is crucial for protecting your skin from the harmful effects of the sun. Here are the key reasons why wearing sunscreen is important:

  • UV Protection: Sunscreen acts as a barrier between your skin and the sun’s ultraviolet (UV) rays. It helps to absorb or reflect these rays, reducing the risk of sunburn and protecting your skin from damage.
  • Skin Cancer Prevention: Prolonged exposure to the sun’s UV rays can increase the risk of developing skin cancer.
  • Sunburn Prevention: Sunburn is not only uncomfortable but also damages your skin.
  • Premature Aging Prevention: Sun exposure can accelerate the aging process of your skin, leading to wrinkles, fine lines, and age spots.

Wear a hat

Wearing a hat when running in hot weather can provide several benefits and help enhance your comfort and safety. Here’s why wearing a hat is recommended:

  • Sun Protection: A hat acts as a shield against direct sunlight. It helps protect your face, scalp, ears, and neck from harmful ultraviolet (UV) rays, reducing the risk of sunburn and long-term skin damage.
  • Temperature Regulation: A hat provides shade for your head, which helps to regulate your body temperature. It prevents excessive heat from directly impacting your head and helps to keep you cooler during your run.
  • Sweat Management: Wearing a hat helps to absorb and manage sweat. It prevents sweat from dripping into your eyes, which can be distracting and uncomfortable. The hat’s brim can also help redirect sweat away from your face.
  • Eye Protection: A hat with a brim or visor can help shield your eyes from the sun’s glare. This improves visibility, especially on bright and sunny days, reducing the strain on your eyes and enhancing your overall running experience.
  • Comfort and Focus: A hat can help keep your hair in place and prevent it from getting in your face during your run. This allows you to maintain better focus and concentration on your running form and performance.
  • Insect Protection: Wearing a hat can act as a barrier against insects like mosquitoes or flies. It reduces the chances of them coming into contact with your head or face while running in areas where insects are prevalent.

When selecting a hat for running in hot weather, choose one made from breathable and moisture-wicking materials to allow for proper ventilation and sweat evaporation.

Adem wearing a running hat
Here’s a terrible photo of me wearing my running hat. It’s aint pretty but it does the job.

Prevent Chafing

In hot weather, sweating can increase friction leading to chafing. Use an anti-chafing product in problem areas before your run.

Acclimatise Yourself

When the hot weather rolls in it can feel almost impossible to do any exercise, but know that your body will acclimatise, and you will feel the effects less as time goes on. Begin with short runs and gradually increase your distance as you adapt to the heat.

I know I feel this way, both shifting into summer but also into winter.

Know when to DNF

Running in hot weather requires careful planning and a mindful approach and hopefully these tips will help you out but remember to prioritise your health and wellbeing over running goals.

If it’s too hot, or you’re starting to not feel well then there’s no harm in cutting a run short, whether that’s on a social run or in a race. It’s best to DNF, stop, and now you’ll be okay to run next time, rather than doing some serious damage and being out for a sustained period of time.

Just remember that cold weather is never too far away and you’ll soon be layering up!

Adem Djemil
I only started running at the age of 37, completing the Couch to 5k course, and since then I've been hooked, running 4 times a week and even completing several marathons and an ultra!