One Ultrarunner’s Guide to Heatstroke and Heat Illness

As an experienced ultrarunner and a professional coach, I though heat illness was something that would never happen to me. Despite being fit, having a solid race plan, and knowing the warning signs, I suffered heatstroke during the Full Moon 50 Miler. I want to share my story so you can learn from my experience. The biggest lesson here is to take heat exhaustion and heatstroke very seriously, regardless to your age, fitness, training history, or knowledge.

How it started…

The Full Moon 50 Miler takes place on Forest Service Roads of the Ouachita Mountains in mid-July, during the hottest and most humid days of Arkansas summer. For 30 years, participants across various distances finish in the early morning under the light of the moon. That meant the 50-mile distance started at 2:00pm. On the start line the temperature was a humid 97 degrees Fahrenheit in the shade with a heat index of 106 F. The temperature was 111 F in the direct sun and most of the course was exposed.

My goal was to win, and I was prepared for every facet of the race. I’m not an elite runner in the big scheme of things, but the pond in Arkansas isn’t huge, although it’s still respectable. There were several seasoned and strong runners in the field, but I was confident.

I was acclimatized to the heat and humidity because I live just a few hours northwest in Fayetteville. Also, I had history on this course because I won the 50K distance in 2021. I was more confident than before any previous ultra race. And I was excited to work through the environmental challenges and display my hard-earned fitness.

Not only was I fit and prepared, but I also have the luxury of working with one of the greatest coaches in the sport of ultrarunning and I’m a full-time professional coach myself. I share this because I understand the strategies required to prepare for performing in the heat. Whatever I lacked in knowledge, my coach filled in the gap. I was as equipped for this race and the environment as I could be.

How it went…

At some point during the race, I suffered from heatstroke. This was despite my fitness, despite my knowledge and expertise, and despite having an unbeatable support network. I got too hot and went into a darker place than I’ve been. I was incapable of making decisions and exerted myself to the point of failure, in just 45 miles.

The scary thing is, I was so confident that I blew through all the warning signs. I never considered I might be experiencing the early onset of heat illness. I’m sharing my experience with you today for two reasons:

  1. I want you to realize heatstroke can happen to anyone, even if you’re fit, have a plan, and know what to look for.
  2. I want you to act when you notice the early warning signs of heat illness in yourself or runners around you. Don’t be like me and keep it all to yourself!

What Happened

My race strategy was to start conservatively, knowing it would be a race of attrition. I held true to my strategy early and hung around 5th-7th place for the first 6 miles. I urinated for the first time, and I was pleased that it was clear. From training, I knew my sweat rate was around 2L/h in 90+ degree heat. It was going to be a daunting task to replace enough fluids and my goal was drink a minimum of 1.5L per hour.

cliff Pittman

Mile 19. Refilling arm sleeves with ice and leaving the aid station in first place.

I executed my hydration strategy perfectly for the first several hours. Unfortunately it wasn’t enough but I wasn’t sure I could tolerate more fluids. I urinated again around Mile 20, which was a little over 3 hours in, and my urine was the color of apple juice. Not great, but not terrible, and a sign my fluid intake wasn’t keeping up with my sweat rate. I knew I had to start consuming closer to 2L an hour. So, at the next few aid stations I consumed extra fluids in an attempt to catch up.

What I was drinking and eating

With such a high fluid intake, I had to be careful to not get low on sodium and develop hyponatremia. As a result, my strategy consisted of 1 serving of sports drink per 500ml, which ensured I got in about 800mg of sodium per L of fluid consumed (every 40 minutes). I chose Skratch, but other brands would have worked, too. Drinking 1.5L of Skratch per hour also put my caloric intake at 240 calories (60g of CHO) per hour. I consumed additional calories and sodium with aid station food to get close to 270 calories per hour.

At Mile 23, I realized 2/3 of the bottles that were refilled at that last aid station contained double servings of Skratch. The bottles had powdered drink mix in them and the volunteers accidentally filled those bottles with pre-mixed Skratch instead of water. Not too big of a deal, but it meant extra sodium and extra calories, both of which can cause some GI issues.

Sometime between Mile 23 and Mile 27, I started to get a minor headache. I thought it might be from getting a little dehydrated, but I was catching up on fluids and I was urinating regularly and clear again. I patted myself on the back for catching up and moved on.

Cliff Pittman

Mile 23. In the lead, looking better than I was feeling.

As I approached Mile 34.5, I began feeling nauseated and my headache became more pronounced. I concluded the nausea/dizziness was because of the hour with extra calories/sodium. I picked up some peppermints at the aid station and quickly moved on, hoping it would settle my stomach.

That was also the turnaround for the out-and-back portion of the course. When I passed second place head on, I was pleased to see I had built a 2-mile lead. I backed off the sports drink at that point because of the nausea and tried to work in different real foods at aid stations. Around Mile 35-36 I turned my headlamp on because it was getting dark – this was the very last thing I remember.

Where things went wrong

I base my training and racing on rating of perceived exertion (RPE). It’s something I have very dialed in and I can replicate on a regular basis, regardless of terrain. From the time I established a lead, at around Mile 20, to the point I can no longer recollect, around Mile 35.5, I mostly stayed within RPE of 6/10 and occasionally touching RPE 7/10. This means I ran the hills with more deep labored breathing and the downhills more moderately and less labored.

Normally, when not in extreme temps, this is very sustainable effort for 50 miles. I was confident enough in my fitness that I intended to maintain the same intensity for the race. However, I didn’t respect the heat enough. I wasn’t looking for warning signs of heat illness to know when to back off the effort. Had I done that when I first experienced a minor headache, I would have spent some extra time cooling off and consuming more fluids in one of the aid stations.

Cliff Pittman

In the ambulance after the sag wagon delivered me to the finish area. I don’t remember being in an ambulance.

Where things went even worse

For the next several hours and over the next 10 miles, I ran with very little presence of mind. I don’t think I ate and I’m not sure how much I drank. I lacked the ability to problem solve for myself. There were no personal support crews in this race. As I went through two different aid stations, I’m sure I was robotic and claimed I had no needs other than fluids.

I wish I would have told someone I didn’t know where I was or what I was doing, but the “light” was off. I was just putting one foot in front of the other without any awareness that something was really wrong. Even worse, I was digging myself a deeper hole as my internal core temperature continued to rise.

From my GPS file I can see that between Mile 40 and Mile 45 I spent a significant amount of time idle. I vaguely remember staggering from one side of the road to the other and vomiting as I hiked. The eventual winner of the race passed me around Mile 42. By Mile 45, I must have laid down on the side of the road.

I have spotty memories of the rest of the rest of the ordeal. I remember a group of runners stopping to take care of me. They waited with me until the sag wagon arrived to pick me up. I got in and did my best to not vomit in the vehicle. I started to cool down in the air condition as we slowly drove 5 miles back to Camp Ouachita, the start/finish area.

Free Ultrarunning Training Assessment Quiz

Take our free 2-minute quiz to discover how effective your training is and get recommendations for how you can improve.

Cliff Pittman

EMT administering an IV while I drank Pedialyte. I have no recollection of this happening, but I’m grateful for such a supportive community!

What is Heat Illness?

Heat illness is categorized into heat exhaustion and heatstroke. The main differentiator is that heatstroke includes an internal core temperature that reaches 104 F. My temperature was not measured until after I had cooled down and I do not know how high it got while I was out on the course.

The hospital and EMTs later informed me I experienced an EHS, or Exertional Heatstroke. This is a serious medical condition that happens when the body overheats and is unable to cool down. Without a body temperature reading from the course, medical professionals determined I had experienced an EHS by my level of delirium.

It was a good 24 hours before I could remember who I was again or respond to anyone meaningfully. If you fully experienced your college years, you might be able to relate. I was trying to piece together what happened, slightly ashamed of myself, and simultaneously grateful for a community who jumped in to ensure I had a cool place to sleep.

Early warning signs of heat illness include:

  • High Body Temperature
  • Hot, red, dry, or damp skin
  • Fast, strong pulse or Fast, weak pulse
  • Headache
  • Dizziness
  • Nausea or vomiting
  • Muscle Cramps
  • Confusion

Although I was fit, prepared for the elements, and had a strategy, I failed because I was overconfident. I pushed through and ignored warning signs of heat illness, and lost my ability to problem solve as my condition worsened.

I never thought heat illness could happen to me. Because of that, I put myself at a significant health risk and set a poor example for other athletes. I also caused a lot of stress on my family, friends, and the race directors; the latter who went to extreme lengths to provide a safe race atmosphere.

Learn From My Heatstroke Experience

In the ten days after my race, I struggled to maintain my core body temperature. For five consecutive days I woke up with a mild fever and struggled even in air-conditioned environments. After a few days back into running, I wasn’t myself and was forced to run very early in the cooler parts of the morning.

For a while after experiencing heatstroke or heat exhaustion, you may be more susceptible to a repeat experience. This is particularly true if you fail to address the causes behind the first bout. For instance, if heatstroke resulted from inadequate training or a poor hydration strategy, continuing to train or race in the heat without addressing training or hydration is likely to result in heatstroke again.

Enjoying This Article? Get More Free Running Training Tips

Get our coaches' best training advice, delivered straight to your inbox weekly. 

This field is for validation purposes and should be left unchanged.


In the short term, I’m still experiencing brain fog, heart palpitations, and general fatigue. Additionally, it might take some time before I’m mentally ready to “go to the well” again in a workout or race.

There are many more warm training runs and races ahead of us this year. And if things continue to trend the way they have, summers will continue growing warmer.

You can prevent heat illness by:

  • Becoming as fit as possible through sound training.
  • Properly acclimatizing/acclimating to the environment.
  • Staying hydrated. Know your sweat rate.
  • Utilizing good cooling strategies in training and racing.

The steps above won’t make you invincible. At the end of the day, Heat Exhaustion or Heatstroke is a negative consequence of poor effort management. So, dial things back a bit and be even more conservative than you think you need to be. Reduce your pace, spend more time in aid stations, and proactive when experiencing minor symptoms of heat illness. Don’t let minor symptoms progress because you may soon lose the ability to make good decisions. More important than any race finish or podium place, stay safe and healthy and identify the early warning signs of heat illness in yourself or someone else.

By Cliff Pittman,
CTS Ultrarunning Coach




Comments 3

  1. Pingback: Ultramarathon Daily News | Fri, Sep 2 - Ultrarunnerpodcast.com

  2. Thanks Cliff, this is a very good wake-up call for all of us, since it’s been a very hot summer for most of the US & many parts of the world. As a desert guide for several decades, I know the importance of being alert to the warning signs, (especially for my clients, many from much cooler climates).
    It can happen rather quickly in some cases, (as you know), and the fact that we lose our ability to make rational decisions, can really compound the case. I’ve also had some bouts with heat exhaustion, and getting back to safety, (especially on your own), can be a real challenge, especially being out in the wilderness.

Leave a Reply

Your email address will not be published. Required fields are marked *