How Pete Kostelnick Fuels 100-Mile Races in Extreme Heat: Badwater Nutrition, Hydration, and Recovery

If you’ve ever wondered how an ultra runner gets through 135 miles in Death Valley heat, this conversation with Pete Kostelnick is packed with practical answers. Pete has finished Badwater multiple times, and he breaks down exactly how he prepares for the heat, what he drinks and eats during the race, and how he recovers afterward.What makes this especially useful is that Pete’s approach is not flashy or complicated. It’s built on testing, repetition, and paying attention to what his body can actually handle. If you’re training for your first 100-miler – or just want to understand how fueling works when conditions get brutal – this is a great place to start.[IMAGE: Pete Kostelnick running in extreme heat with crew support on a paved desert road]
[ALT TEXT: Ultra runner Pete Kostelnick racing in Death Valley heat during Badwater]

What Makes Badwater So Hard?

Badwater is one of the most intimidating races in the world for a reason. It starts at Badwater Basin in Death Valley, about 300 feet below sea level, and heads toward Mount Whitney – the highest mountain in the continental United States. The race is officially 135 miles long, but the iconic “lowest to highest” challenge makes the event feel even bigger.The other major obstacle is the heat. Badwater takes place in July, and temperatures regularly climb into the 120s. Pete explained that the race has seen temperatures as high as 134 degrees in Death Valley, and even the road itself becomes part of the challenge because it radiates heat back at you for hours.That means this isn’t just a test of fitness. It’s a test of heat tolerance, cooling strategy, and how well you can keep moving when everything around you is working against you. [INTERNAL LINK: A guide to heat training for endurance athletes]Why the Course Profile MattersBadwater is not a trail race. It’s all paved road, which sounds easier until you realize what that actually means in the desert.You can move faster on pavement, but you’re also dealing with reflected heat from the surface and very little natural relief from the environment. There’s no shade to hide under, and the long climbs add another layer of stress. Pete described the first major climb as a serious vertical effort, with thousands of feet of climbing early in the race.That combination of heat, elevation gain, and long miles is exactly why a race like Badwater demands more than just “eat when you’re hungry.” You need a plan for fluid, sodium, calories, and cooling long before the race starts.

How Pete Trains for Extreme Heat

Pete doesn’t rely on one magic trick to prepare for hot conditions. His strategy is built around exposure. He gets a lot of his heat adaptation from long weekend runs in the sun, often in the 50- to 70-mile range.He said he sometimes underestimates heat training, which is a good reminder that even experienced runners can get casual about the basics. But his core method is simple: spend time running in the heat, keep the body exposed to it, and avoid using too much cooling during training.

Active Heat Training Beats Comfort

Pete’s approach is more about adaptation than comfort. He’ll run in the sun with little or no cooling so his body has to deal with the stress directly. In his words, that “torturing yourself” style of training goes a long way for Badwater.He also lives in Flagstaff, Arizona, where the altitude keeps temperatures lower than Phoenix, but the sun is still intense. Even low 90s can feel brutal when you’re running at 7,000 feet and absorbing direct sunlight for hours.If you want to apply this idea to your own training, the lesson is clear: don’t wait until race day to find out how your body handles heat. Gradually build exposure during key training blocks, especially on longer runs. [INTERNAL LINK: How to prepare for a hot race without overcooking your training]Gear Can Help – or HurtPete shared one important gear lesson from this year’s race: the wrong shirt can make a big difference. He wore a sun shirt, hoping it would stay wet and cool him longer, but by later in the race it dried out too quickly and felt too thick.In previous years, he had used more breathable singlets or thinner long-sleeve options. The difference might sound small, but in an event like Badwater, small differences matter. If a shirt traps heat or dries too fast, you lose evaporative cooling – and that can change how well you handle the back half of the race.

Pete’s Badwater Fueling Plan: Fluids, Sodium, and Carbs

This is where Pete’s race strategy gets really practical. During Badwater, he’s often taking in a huge amount of fluid – sometimes around 70 ounces per hour – along with roughly 2,000 milligrams of electrolytes per hour. That sounds extreme, but in those conditions, it’s necessary.He doesn’t build that number from theory alone. He arrives at it through repeated experience in training and racing. If he’s running hard in the heat, he knows his fluid demands can jump dramatically compared with cooler conditions.

Hydration Is Situation-Specific

Pete pointed out that his hydration needs can vary wildly depending on temperature. In cool conditions, he might need only about 1 ounce per mile on a long run. In the heat, that can become more than 10 ounces per mile.That’s a huge reminder that hydration is not one-size-fits-all. Your needs change based on pace, temperature, sun exposure, and how much you’re sweating. The takeaway isn’t that you should copy Pete’s exact numbers. It’s that you should test your own fluid strategy in the conditions you’re likely to race in.He also explained that he doesn’t do highly scientific sweat testing. Instead, he learns from training: if he gets home from a run and still feels dehydrated or crampy, he knows he underfueled. That kind of self-observation is often more useful than chasing a perfect lab number.

Carbs: More Simple, Less Guesswork

For Badwater, Pete uses a highly structured fueling schedule. He plans out eight different nutrition items and cycles through them every 30 minutes, which repeats across a four-hour block. In total, he aims for about 1,800 calories every four hours – roughly 450 calories per hour.That’s a lot of intake, but Pete found that it worked better when he leaned more heavily on sports nutrition rather than solid food. This year, he reduced the amount of traditional solid food and used more gels, drink mixes, and specialized products.He still kept a few solids in the mix, including a Honey Stinger waffle with peanut butter and a chew bar, but the majority of his calories came from easier-to-digest race fuel. That shift reduced the guesswork and made it easier for his crew to stay on schedule.

Why He Moved Away from More Protein During the Race

One of the most interesting changes Pete mentioned was his evolving view on protein during ultra races. Earlier in his career, he believed more protein was better and would even push 5 to 10 grams per hour.Now he’s less convinced that’s necessary during racing, especially in extreme heat. He found that as the race went on, protein-heavy foods were the least appealing and sometimes harder to tolerate. In Badwater, the only meaningful protein he got was from peanut butter.That doesn’t mean protein is unimportant overall. It means timing matters. During the race, the priority is keeping carbohydrates and fluids moving through your system without creating GI distress. Protein can be more useful before and after than during the hardest hours of racing.

How Crew Support Changes Everything at Badwater

Badwater is unusual because it’s as much a crew race as it is an individual race. Pete sees his crew roughly every two miles, and that support structure is built into the event. There aren’t traditional aid stations in the same way you’d see in many other ultramarathons.Instead, he relies on a minivan, a small crew, and a very precise handoff system. He said his crew was able to keep things moving efficiently by passing bottles, ice, and nutrition in quick succession. Sometimes he’d run by and have one person take items from him while another was already waiting farther down the road with the next handoff.That kind of rhythm matters because it saves time and reduces friction. When you’re trying to move for nearly 24 hours in extreme heat, even a small delay can throw off your schedule.

Why Simplicity Helps the Crew Too

Pete often has a very specific item coming every 30 minutes, so his crew knows what’s next without having to improvise. That makes the whole operation smoother and lowers the chance of mistakes.It also explains why he likes having a plan that is as repetitive as possible. If the crew can memorize the rhythm, the athlete can stay focused on moving and responding to conditions. In a race this long, the fewer decisions you have to make on the fly, the better.

Caffeine Is Part of the Plan, Too

Pete’s race nutrition also includes a meaningful amount of caffeine. He used a Science in Sport gel with about 200 milligrams of caffeine every four hours, plus a small amount from Mountain Dew. Over the course of the race, that adds up.He noted that one crew mistake gave him two caffeinated gels too close together, which made him joke that they were “going to make my heart explode.” The incident highlights something important: caffeine can be useful, but dosing matters. Too much too soon can become a problem.Pete believes caffeine helps him perform, but he also wonders whether the ultra-running context changes how it feels compared with daily life. Because he’s moving for so long, his body may process it differently than if he were sitting still.

What Recovery Looks Like After a Race Like Badwater

Pete’s recovery story is almost as interesting as his race-day strategy. After a big event like Badwater, he’s hungry – sometimes extremely hungry – but this year he noticed his appetite wasn’t as intense as after some previous races.That can happen for a lot of reasons: pacing, how hard you went late in the race, how much your GI system was taxed, and how well you stayed on top of intake during the event. Pete said he did fall behind on calories near the end because he may have overdone it on electrolytes, which backed his stomach up and made it harder to keep fueling.Even after finishing, there’s still a challenge: getting down the mountain. The final drive is short in mileage but slow enough to feel miserable after nearly a day of racing.

The First Thing He Wants After Finishing

Pete’s immediate post-race craving is not sweet sports nutrition. It’s savory, salty, real food. He wanted a burger or pizza – anything that was not race fuel.That’s a common ultra-runner pattern. After hours of gels, drink mix, and sweet products, your body often asks for something completely different. He also said he likes to get calories in as soon as possible because doing so helps him avoid feeling completely wrecked the next day.For Pete, the exact food matters less than the timing. He wants to start the recovery process right away.

Recovery Is Faster Than It Used to Be – But Still Serious

Early in his career, post-race recovery could take weeks. Now, after years of ultra racing, he can usually start active recovery within four or five days and return to a workout or long run within about two weeks.That doesn’t mean the body is fully fresh. It means he has adapted to the repeated stress of ultra racing and learned how to recover efficiently. He uses recovery boots and focuses on getting enough protein after a long race or training run, especially when hunger is high.He doesn’t rely heavily on supplements like tart cherry or omega-3s. His biggest recovery strategy is simple: get calories in quickly, then keep eating enough in the days after.

The Biggest Fueling Lessons for Your First 100-Miler

If you’re training for your first 100-mile race, Pete’s advice is refreshingly straightforward: don’t underfuel before, during, or after.He believes many runners make the mistake of thinking they can match their calorie burn during the event. You usually can’t. Instead, you should go into the race fully fueled, stay as consistent as possible, and then prioritize recovery nutrition the moment you’re done.That lesson applies whether your race is in the heat of Death Valley or on a cooler course elsewhere. Long efforts create a huge energy deficit, and the sooner you respect that, the better your chances of finishing strong and recovering well.

Pete Kostelnick’s Badwater strategy shows that ultra success comes from disciplined heat training, a practiced fueling plan, smart crew support, and fast recovery after the finish.

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