As temperatures soar, many runners face a familiar dilemma. While sunny skies are a welcome sight, clocking miles in uncomfortably high heat can feel like an impossible task.With global temperatures on the rise, learning how to adapt is more important than ever.
So, how do you run safely when the weather heats up? From drinking effectively to dressing wisely, these top tips will help you to run sensibly in higher temperatures. Here is what the team of experts at Runner’s World want you to know about how to clock miles safely in hot weather.
What’s the best way to run in hot weather?
The good news 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, opt for some slow, easy runs, since lower intensity efforts produce less heat in the body. Moderating intensity or planning in lower intensity focus sessions during a heatwave is a good strategy to keep training on track while minimising risks.
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 better of it when you understand what this does to you physiologically. Running and other forms of physical activity involve muscular work. 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,’ says 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?
Pate says that you should keep on top of your hydration before, during and after a run in hot weather to ensure that your body can cool itself correctly. Recommendations on how much additional water you should consume per hour during a run vary from 300-800ml, so consider things like the temperature and humidity, how much you usually sweat and your level of thirst. To help you stay hydrated, run in a hydration pack or carry a water bottle with you so that you can sip water regularly.
If you’re running longer distances, you’ll need to be even more careful with your hydration and consume electrolytes to make that you’re replacing both the water and salts lost through sweat.
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. Minimising exposure to direct sun is also a good idea, as it will exacerbate ambient heat.
How quickly does your body to acclimatise to heat?
After time, it is possible for the body to become accustomed to running in hotter temperatures. 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.
Tips for running in the heat
Here are some more tips from Runner’s World columnist Cory Wharton-Malcolm, on how to run safely during the warm summer months.
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.
Add salt
As mentioned, running on a hot day means more sweating – and you lose sodium as well as water when you sweat. Leading sports dietitian 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, sports drinks and real food.
Douse yourself
According to a recent 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.
Adjust your goals
As research indicates, running performance drops off fairly rapidly when temperatures reach 18°C or higher, so don’t attempt to hit the same paces that you’d regularly hit when it’s cooler. Instead, monitor your effort level or train by heart rate instead of pace to make sure that you’re not overreaching when it’s warm. As you adjust to running in the heat, you’ll be able to go faster at the same number of beats per minute.
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 to keep you cool and a pair of sunglasses to keep the glaring sun out of your eyes.
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. Be sure to apply it liberally, too – most of us only use about half the required amount.
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.
Hit 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.
Use the treadmill
If you have access to an air conditioned gym, run inside on a 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.
Original article by Jenny Bozon & Rachel Boswell published on Runner’s World.
