If you were a spectator for a marathon and you thought the weather was perfect, it's likely it wasn't great for the runners. Perfect marathon-spectator weather is a 65° to 75° cloudless-day. For runners, these are brutal conditions. Runners in +60° conditions will likely experience heat exhaustion, dehydration, GI issues and become light-headed and/or pass out. Especially if the runners are participating in a spring marathon as those runners most likely trained through colder weather. Acclimating your body to hotter race conditions is essential and possible. Acclimate your body.
According to the CDC, it takes workers 1-2 weeks to acclimate to a hotter climate. And, according to the Gatorade Sports Science Institute, "Generally, about 1-2 wk of ~90 min daily heat exposures are required; but highly aerobic fit athletes can heat acclimatize." So unless you are an "highly aerobic fit" athlete, then you should consider the following before lining up on race day:
Sit the race out or drop out. You didn't train for the conditions. It's too hot and your truly not sure. Hot weather can sideline any athlete on race day. Play it safe and do the responsible thing and sit the race out. Humidity and high heat can make managing your internal core temperature difficult to manage and it's important to keep your core cool for optimal performance and survival. Know when to stop and seek medical attention.
Hydrate. Hydrate. Hydrate. Drink plenty of fluids leading up to race day. This doesn't mean chugging cups of fluid to the point of discomfort. Chugging isn't a good practice either. By drinking too much fluids at one time, you could over dilute yourself and end up pissing away (literally) essential vitamins and electrolytes that bind with water to help you retain and stay hydrated. Get out in front it and implement a hydration and nutrition regimen at the start of your marathon training. Also, learn to drink room-temperature fluids during training so that your body can efficiently process the fluids. This is because it can be absorbed without your body having to warm it up first, unlike cold water. On race day, drink a cold beverage as you head to the start line. This is to keep the core (your organs) as cool as possible before toeing the line.
Eat hydrating foods like fruits and vegetables and implement meal portion control. Grab up a smoothie, eat a vitamin rich salad, and avoid salty high preservative meals. We know pasta and meat sauce are the go-to pre-race meals (you should definitely have pasta) but substitute the side of fries with a side salad or snack with fruits and/or smoothie to get the vitamins and hydration all in one take. The days leading up to race day, avoid binge eating as you don't need to over-indulge on carbohydrates to fill your glycogen stores. The decrease in mileage and carbohydrate-focused eating will be enough to fill your glycogen needs. This will help minimize GI distress. That said, if you trained in much colder temps as compared to the race day conditions, you are still susceptible to GI issues. Also, eat the portion size of food you are comfortable eating. This will allow you to digest your food and may curb GI distress.
Simulate running in the heat. 2 weeks out from race day, you'll usually be able to get a sense of what the weather is going to be like and plan to adjust your training accordingly. Most gyms are 65° - 68°, so get on the treadmill (throughout training or 2-3 weeks out), bring some hydration with you and get your body ready for warmer temps. In general, get on the treadmill throughout your training cycle so that you've provided your body ample time to acclimate to varying race conditions.
Race day tactics and adjust your expectations. Wear lightweight, breathable and sweat wicking material. You're going to be sweating, a lot! Wear light reflecting colors (white, beige or light-grey) and stay away from dark materials. If you're doing a warm-up, keep it light and in the shade. While running the race, make sure to take advantage of any shade along the route. However, be mindful of other runners on the course and that you want to run the tangents. If you're really feeling the heat, don't hesitate to pour cold water over your head and neck. Make sure to lower your race performance expectations, if you're really feeling the heat.
Again, sit it out or drop out.
Know when to stop and/or sit out the race. If you haven't trained for the heat and humidity, take a rain check and consider the steps above to get your body and mind acclimated. If you become lightheaded, dizzy and/or just not able to handle the heat, walk off the course and get cool.
If you like what you see subscribe, comment and follow us on social below:
The information provided on Ardsley.org is for educational and informational purposes only and is not intended as medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on Ardsley.org. Reliance on any information provided on Ardsley.org is solely at your own risk. The owners, creators, contributors, and publishers of Ardsley.org  are not responsible for any errors or omissions in the content or for any outcomes related to the use of the information provided. Ardsley.org may contain links to other websites or resources for informational purposes only. We do not endorse or accept responsibility for the content or accuracy of these linked websites or resources.
Resources:
Centers for Disease Control and Prevention: https://www.cdc.gov/niosh/topics/heatstress/acclima.html
Gatorade Sports Science Institute - Heat acclimatization to improve athletic performance in warm hot environments: https://www.gssiweb.org/sports-science-exchange/article/sse-153-heat-acclimatization-to-improve-athletic-performance-in-warm-hot-environments