Running in the Heat: Essential Safety Tips and Considerations

With the current heatwave, I've had lots of questions about how I can even run in the heat but also how others can run safely in hot weather. While these temperatures are more intense than we're typically used to, I personally don’t avoid running in warm conditions all together. I’ve done a few desert marathons, I know my health status, my body, take lots of precautions, and adjust my pace and expectations accordingly.

Whether you're out on coastal routes with a welcome sea breeze or tackling inland trails or beach running like me (though nothing quite compares to the sand levels of Wadi Rum in Jordan!), running in heat requires careful consideration and preparation.

Running in the heat

If you are thinking about heading out for a run in the heat, here are some essential things to consider:

Before you even go out of the door…

Ask yourself: Do you really need to run in the heat? If you're not used to it or haven't done it before, or don’t need to do it, now is not the time to start. Running in the heat isn’t just about mental grit — heat acclimatisation takes time and should be built up gradually.

Consider timing. Could you go out early when it's cooler? Dawn runs not only avoid the peak heat but often provide the most beautiful, peaceful running conditions. Generally you should avoid the middle of the day.

Start prepared. Always begin well hydrated and having eaten. Your body needs fuel and fluid reserves to cope with the additional stress of heat.

What to Wear

Sun protection is non-negotiable. Apply sweat-resistant sunscreen (SPF50 or higher) before heading out and reapply if you're running for over an hour and/or sweating heavily.

Choose your clothing wisely. Wear the shorts – please don’t run in leggings or long sleeves (unless its for cultural reasons of course) If you do, opt for lightweight, breathable, moisture-wicking fabrics to help keep you as cool as possible. I also choose clothing with UPF protection built in and go for lightweight vests and shorts in the heat.

Protect your head and eyes. Wear a hat or visor to keep the sun off your head and face, plus sunglasses. You need to protect your corneas in the sun, and psychologically it helps you feel cooler too.

Desert running gear

Hydration and Nutrition

Carry more than you think you’ll need. Heat increases fluid loss rapidly — you can lose 1–1.5 litres of sweat per hour in hot conditions. Dehydration also increases heart rate and perceived exertion.

Put 1 -2 small soft flasks in the freezer the night before. If you are wearing a race vest or waist pack it will defrost as you go plus keep you cool too.

Plan your refueling strategy. On longer runs, consider routes that pass shops or cafes where you can top up your fluids.

During Your Run

Listen to your body. If you don't feel 100%, stop and turn back. Heat exhaustion symptoms can develop quickly and aren’t something to push through.

Alter your pace dramatically. Research shows performance drops by 6–26% in non-acclimated runners under hot conditions. Unless you're a multiple winner of Marathon des Sables like Rachid El Morabity, this is not the time for speed—slow down, walk when you need to, and keep hydrated.

Choose your route wisely. Shade, breeze, and trail surfaces matter. Avoid tarmac where possible—it radiates heat so you will feel hotter! Stick to shaded trails or areas with breeze exposure if you can. Pick well served routes where you can access additional water, food and transport sources in case you need them.

Safety First

Let someone know your plans. Always take a fully charged phone with you, tell someone your route and expected return time, and carry money or a payment method in case you need to cut things short or get transport home. Even if you are running with a friend, this is good practice. Don’t assume your friend is carrying a phone and/or its charged!!

Know the warning signs ( the NHS guidance on this is referenced below). Watch for symptoms of heat exhaustion: heavy sweating, dizziness, nausea, confusion, or cessation of sweating. If any of these occur, stop immediately, find shade, cool down, and seek help if needed.

Building Heat Tolerance

Heat tolerance doesn’t happen overnight. It takes roughly 7–14 days of consistent exposure for your body to begin adapting to the heat. Start with shorter runs or walks (20–30 minutes) in mild heat and gradually build duration and intensity. Key adaptations include improved sweat response, lower heart rate, and better fluid retention.

Research has shown that running 60–90 minutes per day in hot environments over 5–10 days improves performance, reduces perceived effort, and enhances core temperature regulation. These gains can help make summer training safer and more effective—but only if introduced gradually and sensibly.

Ready to Improve Your Running?

If you're looking to improve your running performance, support for running in warmer climates or train for longer distances, I'd love to help you develop a plan that works with your lifestyle and goals. Whether you're preparing for your first 5K or training for an ultra-marathon, proper guidance ensures you progress safely and effectively.

Book a consultation through the website to discuss how we can work together on your running journey.

Further Reading

• Périard JD et al. (2021). “Exercise in the Heat: Challenges and Adaptations.” Environmental and Experimental Physiology.

• Garrett AT, Creasy R et al. (2020). “Heat Acclimation Improves Performance: A Meta-Analysis.” Sports Medicine, 50(6), 1167–1177.

• Racinais S, Alonso JM et al. (2015). “Consensus Recommendations on Training and Competing in the Heat.” Scandinavian Journal of Medicine & Science in Sports, 25(S1), 6–19.

• Ely BR et al. (2020). “Running in the Heat: Performance Consequences and Hydration Guidelines.” Strength and Conditioning Journal.

• NHS (2024). Heat exhaustion and heatstroke. Available at: nhs.uk