This article was originally written before the 2018 London Marathon, when we were due to have very warm weather. If you are running a very hot marathon, this advice can really help make the most of your race.
Some runners will cope better than others in the heat. Unfortunately we've had cold and wet winter, where most runners will not have had the chance to train for any length of time in warmer temperatures. To help you prepare for warm conditions, we have some last minute tips for race day
Be flexible with your race plan
You will need to slow down to prevent yourself from overheating. If you go off too fast, your heart rate will spike as it battles to keep your body cool at the same time as your muscles demanding oxygen.
A slower start might mean you don't run that Personal Best or goal time you were looking for, and it certainly takes a brave athlete to stand on the start line and make this decision. However if conditions aren't going to be favourable you have to respect them to run your best race possible in them. This is part of the draw of racing half and full marathons. You do months of training for one day of the year, and then have to deal with whatever is thrown at you.
Less is certainly more when it comes to clothes in the heat, make sure you aren't overdressed. Especially if it is a bit cooler at the start of the race, be mindful that you will warm up.
You can certainly accessorise to help yourself in the heat. A cap is a good way of keeping the sun off you (ideally it should be well ventilated). You can always take it off and cover in water before putting back on!
A 'buff' can also be soaked in water at times during the race, and put around your neck, wrists or even used as a headband.
Whilst sunglasses aren't going to keep you cool, they will stop you from tensing your face if the sun is in your eyes, this will help keep you relaxed. A tense face can easily translate to tense muscles elsewhere.
Be aware that your feet might swell up a bit more than usual in the heat. Lightweight running socks will certainly help here.
Drinking and electrolytes
Drink to thirst is still the best advice when racing. You don't need to drink at every single water station.
The problem with just drinking water is that it hardly contains any electrolytes in it (sodium and potassium to name two). When you sweat you lose these electrolytes along with water. Your body wants to keep these electrolytes in balance. If you are just drinking water, you aren't actually rehydrating yourself, you are just watering down that water to electrolyte balance.
By adding in an electrolyte tab into your water, you can help replenish the electrolytes you are losing. Most electrolyte tablets turn water into a pleasant soft drink, so shouldn't upset your tummy on race day. We'd certainly recommend trying some this coming week though and then using on race day.
Keep yourself comfortably cool before the start and then during the race. Wait or run in the shade whenever possible. Some water on the back of your neck will help and even some splashes on your legs. Watch out for some showers placed around the course on Sunday too. Running through them will provide some respite from the heat. Just be careful that you don't get your feet really wet as that can cause rubbing.