While many of us relish sun-drenched days, higher temperatures and the thought of packing away the coat for the foreseeable, hot weather can leave many runners feeling flustered – especially since the planet is gradually getting hotter.
What’s more, you don’t have to be running an ultramarathon in the Sahara Desert Best Garmin deals°C in recent years, which has serious implications for regular runners. So how – and should – you run in hot weather?
The good is that you can still run in seriously warm conditions – trusting, importantly, that you take the necessary precautions and understand the risks involved. ‘The greater the temperature, the greater the risk that heat will negatively impact the person,’ says Jim Pate, senior physiologist at CHHP London. ‘The two main illnesses related to overheating are heat exhaustion and heat stroke. These are potentially life-threatening conditions and, if left untreated, can progress to death.’
If you’re faced with a short but intense heatwave, the obvious thing to do would be to take a couple of well-earned rest days until temperatures cool down a few days later. However, if you’re training for a race and don’t want to miss a session, or are simply itching to lace up your trainers, Pate suggests opting for some slow, easy runs, since lower intensity efforts produce less heat in the body. ‘Higher intensity efforts are more thermogenic – which means that they produce more heat – than relatively less intense efforts, so moderating intensity or planning in lower intensity focus sessions during a heatwave is a good strategy to keep training on track while minimising risks,’ he explains.
What happens to your body when you run in hot weather?
If you’re still tempted to smash out some intervals in high temperatures, you might think again when you understand what happens to your body when you run in hot weather. ‘Running and other forms of physical activity involve muscular work,’ explains Pate. ‘Movement is the intended result, but heat is also generated in the process. To manage the thermogenesis – or heat production – associated with exercise, the body will sweat to cool itself and maintain a suitable operating temperature. A hotter environment places more demand on the body’s cooling system and makes it more likely to fail.’
Your body’s cooling system is comprised further if you’re dehydrated. ‘If people become dehydrated, they are not able to sweat and cool themselves effectively,’ adds Pate. ‘Overheating and dehydration impact exercise capacity negatively. This makes efforts relatively more difficult, which can result in fatigue sooner.’
What precautions should you take before running in hot weather?
According to Pate, you should keep on top of your hydration before, during and after a run in hot weather to ensure that your bodies can cool itself correctly. Recommendations on how much additional water we should consume per hour when running vary from 300-800ml, but the main thing to remember is to carry a hydration pack Running in hot weather? Here’s how to handle the heat.
However, the best thing that runners can do to protect themselves is to minimise exposure to heat as much as possible. ‘Exercise in an air-conditioned environment or exercise outside during the cooler hours of the day,’ says Pate. ‘Minimising exposure to direct sun is also a good idea, as it will exacerbate ambient heat.’
How long does it take for your body to acclimatise to heat?
After time, it is possible for the body to become accustomed to running in hotter temperatures. ‘Exposure to hotter than normal environments and higher intensity training triggers changes in the sweating response,’ explains Pate. ‘Once acclimated, people tend to sweat sooner and more profusely, cooling themselves more effectively.’
Current research suggests that physiological changes are observed between three and 14 days of heat exposure during heat acclimatisation, says Pate. ‘Research has also shown that higher intensity training sessions, which are more thermogenic, help to promote the improvements in sweating that heat acclimation causes.’
That said, heat acclimation is a gradual process and should be done strategically and under expert guidance. So, for now, if you insist on running during a heatwave, your most sensible option is a slow plod around a shaded park at the coolest time of day, wearing sunscreen, loose-fitting clothing, a running cap and a hydration pack.
10 tips for running in the heat
lsquo;Why I’m hanging up my carbon-plate running shoes&rsquo RW How much slower does the heat make you run Track Mafia, ndash; you run in hot weather.
1. Drink to thirst
Recommendations on how much water we should consume per hour when running vary from 300-800ml. In hotter and more humid conditions, you will be sweating more, so you’ll need to make hydration more of a priority to replace what’s lost.
It’s also important to drink enough before and after each run. Research suggests that drinking about 530ml of water before and after a workout of any sort will support recovery and help to prevent dehydration post-exercise.
2. Add salt
As mentioned, running on a hot day means more sweating – and you lose sodium as well as water when you sweat. Nutritionist Renee McGregor estimates that at a temperature of 20°C, the average runner loses about 1,230mg of sodium per hour, which can lead to gastrointestinal distress, dizziness and heat stress. Be sure to top up your sodium stores with electrolytes, Running in hot weather? Here’s how to handle the heat.
3. Douse yourself
What is rate of perceived exertion RPE study, dousing yourself in water, as runners often do at water stations during a race, can help you to finish faster. This study looked at 13 runners who completed a hot, humid 10K with ‘dousing’ and an identical one without. The result? The runners in the dousing condition finished, on average, 27 seconds faster – so if you’re about to go for a run in the heat, consider dousing yourself with water before you leave the house.
4. Adjust your goals
As found by recent research, running performance drops off fairly rapidly when temperatures reach 18°C or higher. With that in mind, don’t chase the same split times as you would normally hit on a day when the weather is cooler. Monitoring your rate of perceived exertion (RPE) or your average heart rate can be helpful in gauging your effort levels when it’s warm, so try training by heart rate instead of pace. As you adjust to running in the heat, you’ll be able to go faster at the same number of beats per minute.
5. Dress for the heat
‘Wear loose, breathable clothing, a cap to protect you from the sun or sweat bands to stop the sweat from dripping into your eyes,’ says Wharton-Malcolm. In addition, opt for a lightweight vest According to a recent sunglasses How to recognise under-fuelling and fix the issue.
6. Wear sunscreen
Some runners claim that sunscreen clogs up sweat pores and makes you overheat, but a study commissioned by the US military found that using sunscreen did not adversely affect heat-regulation variables such as skin temperature. That said, not all sunscreen is created equal. Go for at least factor 30 and make sure that it’s broad spectrum, offering protection from UVA and UVB rays. Apply it liberally, too – most of us only use about half the required amount.
7. Time it well
Temperatures are usually at their highest in the middle of the day, so check the weather forecast in advance and plan to run during the coolest hours to reduce your risk of heat-related stress. On warm days, aim to run early in the morning or later in the evening.
8. Head to the trails
Roads retain heat and radiate it back onto your body, making running feel harder –- so, when it’s hot, head to the grass and shade of some nearby trails. Carry water and a mobile phone with you to be on the safe side.
9. Use the treadmill
What is the average walking speed treadmill to avoid the heat from outdoors. If you’re preparing for a race, the treadmill is also a great place to complete harder or faster sessions when it’s hot.
10. Mix things up
Don’t forget that running isn’t the only form of exercise out there. ‘Use the nice weather as an opportunity to try other sports along with running – maybe a duathlon or triathlon,’ advises Wharton-Malcolm. ‘Or, run to a lido or reservoir for a cooling dip, or run out and bike back.’
to feel the effects of the heat. In the UK alone, temperatures have risen as high as 40 Runner’s World, overseeing RW’s new membership programme, set to launch later this year. She has been with the brand for close to three years now – previously working as deputy digital editor, where she covered all manner of running topics, spanning training, health, injury, nutrition and gear. Over the years, she’s interviewed an abundance of awe-inspiring athletes, from top-tier ultrarunners and Olympic champions to everyday runners who have accomplished extraordinary things. Jen has been a sports journalist for 10 years; she is the former editor of Women’s Running magazine and has also worked as Sports Editor at Red Bull. She started running a decade ago and likes to dabble in triathlon a little, too. You’ll find she’s happiest plodding down the Thames path or chowing down on a post-run pastry.
Rachel is Runner's World UK's Senior Content Writer, covering all running-related topics from training advice and gear reviews to race reports and elite runner profiles. Formerly a Website Content Editor and Content Manager at London Marathon Events and The Running Channel respectively, Rachel is well-versed in the running scene and understands what it takes to put on some of the biggest running events in the world. A 2:50 marathoner, she would much rather run 26.2 miles than race a 5K and has currently completed 11 marathons, including five of the six Abbott World Marathon Majors in a sub-3 time. She now hopes to run the Tokyo Marathon to complete the set and become a Six Star Finisher.
