There was once a time when William Byron would get through the opening stage of a NASCAR Cup Series race, and he already felt like he had gone the distance.
It wasn’t that he wasn’t fit enough. Byron was simply spending way too much energy fighting everything: the car, G-forces, the duration of the race, and even his own tension.
“When I first got into Cup, just getting used to the length of the races was the biggest thing,” Byron told M&F. “You’re in the car for three to four hours, and my first year, I feel like the first stage, which is the first 80 or so laps, would go by, and I would just be exhausted. I would spend all my energy in that first stage, fighting the car.”
Years later, Byron has evolved. He’s learned that elite racing fitness isn’t about just becoming stronger or even developing a better VO2 max. There’s an entire science to it.
The faster you’re moving, the less energy you can afford to waste. This realization has helped shape nearly each aspect of Byron’s preparation. His training during the season focuses on mobility and core stability over simply adding muscle, with recovery changing as the season progresses.
His sleep is monitored closely. He replenishes fluids and carbs immediately after races and has learned that sometimes skipping a hard workout is more valuable than forcing one in.
The mental side has undergone an equally important evolution. Byron began working with a sports psychologist to better understand pressure, anxiety, confidence, and his tendency to attach further weight to results. The work has helped him learn how to leave the prior race behind before preparing for the next.
Whether he’s recovering from the physical strain of a particularly hot Sunday or the results aren’t up to his expectations, his principle is now always the same: Don’t fight what doesn’t need to be fought.
Prosport Management
Learning How To Relax at Speed
There isn’t a workout available that can replicate driving for hours in a firesuit while tightly restrained against a seat, temperatures rising around you as you have to make consistent tiny corrections to keep a car traveling at high speed from sliding beyond your control.
All of this while remaining calm and composed.
It’s possibly one of the most overlooked and least appreciated physical skills in the sport. Byron compares finding a rhythm inside the car to distance running. There’s a pace the body needs to find, and unnecessarily elevating the heart rate early can eventually become costly.
“No matter what’s happening on the track, I try not to let that affect my heart rate and just keep a nice, level heart rate,” he says.
When a caution arrives, Bryon uses it like a mini cooldown period, loosening his seatbelt, and relaxing his body some.
For those thinking it’s just a circular sprint, Byron says the temperatures inside the car might be one of the biggest shocks for someone experiencing a Cup car for the first time. There’s no AC, and nowhere to escape the heat.
“It’s so hot and concentrated,” Byron says. “The more you panic or the more that you try to fight that heat, the worse it is.”
Byron trains in hot conditions as well as uses sauna sessions as tools for climate acclimation. Hydration is essential, but so is adjusting to being uncomfortable. You toss in the G-forces and the constant interaction with the car, and you realize that this is almost grappling at high speed while trying to maneuver past 30-plus other drivers who are doing the same.
Understanding this is what has changed his understanding of what being race-ready means. It’s not about seeing how much tension his body can tolerate but using as little as possible.
Prosport Management
Training for Mobility, Not Just Muscle
Byron’s offseason is where he has freedom to chase physical gains. If he wants to add muscle, improve cardiovascular capacity, or address any other areas of interest, that is the time to push. Once the season starts, the objective moves from building to maintaining.
During the season, Byron generally trains around three times per week. Mondays are spent on recovery, with his more structured work beginning on Tuesday at the Hendrick Motorsports gym.
“We’ll start with cardio stuff, like a rower, SkiErg, and assault bike,” Byron says. “Then we go into sets of different lifts. A lot of it has mobility included because I don’t want to be too stiff.
“We don’t do a lot of barbell stuff. Most of the stuff is with dumbbells and kettlebells because we want to stay mobile.”
Band work helps keep the joints continuing to move fluidly. This is important because once he’s strapped into the seat of the car, the straps are pulled extremely tight across his body, making the focus on mobility in the shoulders and upper back even more important.
Lower-body work and squats are also a huge part of the programming, but core work is a non-negotiable. A stable midsection gives Byron a better platform against the forces pushing him around inside the car.
“That is one thing that really helps with the G-forces,” he says. “A stable core keeps you in the same place in the seat, so you don’t have to fight the Gs as much.”
Another adjustment Byron makes as the season progresses is being extremely selective about how much stress he adds outside the car. Earlier in the season, his body recovers quickly enough to comfortably train several times per week. Later in the season, and those same sessions require significantly more recovery.
As fatigue complies, he begins to devote an entire day, and sometimes a day and a half, to recovery instead of just a half day. With travel typically taking over Friday through Sunday, Byron tries to contain most of his training to Tuesday through Thursday.
Byron and his friends sometimes sprint on Thursdays. He enjoys it, but a hard session in the summer heat before a hot race weekend can deplete more than it can be helpful. This is where consistency becomes more valuable than intensity.
Instead of focusing on winning every workout, Byron focuses on remaining active and acclimated. During the summer, this is as simple as spending time outdoors to help ease the feeling of sitting in a car where temperatures are routinely up to 40 degrees hotter than the outside temps.
Recovery Starts Right After the Checkered Flag
Post-race recovery starts with replacing what was lost during the race. First comes fluids, then electrolytes, and then a treat.
“One trick is to get sugar after a race,” Byron says. “Fruit or anything with sugar directly after the race is really helpful because your glucose level gets really low in the car.”
Protein becomes more of a priority the following day as he begins rebuilding and preparing for another week. Hydration remains a focus, and it can’t be stressed enough the value of rest after the stress one race places on the body.
“I’m pretty obsessed with my sleep,” Byron says. “So I watch it and evaluate.”
Even hours after a race, sleep is hard to come by. Byron says he can wake up overheated or due to feeling what he describes as almost a hungover feeling, with dehydration making it more difficult for his body to settle into quality rest.
It goes to show just how vital every day of the week is to a driver performing their best at the end of it. Fitness isn’t just what happens during a workout. Training only works when the body can absorb it, recover, and remain capable of performing when it matters most. For Byron, the hardest session of the week won’t mean much if it leaves him depleted when he climbs into the car.
Prosport Management
Sports Psychology Helped Byron Stop Bringing Sunday Home
In sports, improvements to the physical side of an athlete’s preparation are always a point of emphasis.
At a certain point, Byron began feeling like he was “leaving something on the table” mentally. That realization led him to working with a sports psychologist. His initial goal was focused on his performance: become more consistent in how he approaches races and better understand the thoughts that produced pressure or anxiety before competition.
However, with each session, it grew into something more encompassing.
“How can I be more consistent in my approach and really understand why I do things the way I do?” Byron says. “That’s really where it started, and I think it bled into all aspects of my life.”
Byron describes himself as “mastery focused.” He enjoys the process. More importantly, he has learned to value process wins rather than allowing the finishing order to dictate how he feels about his performance.
Those small wins create a ripple effect and create confidence he can carry forward regardless of what appears on the results sheet. It’s an approach that has helped Byron put boundaries around disappointment.
Earlier in his career, the emotions from a bad race lingered.
“I used to think about the previous race all the way to the next weekend,” Byron says. “Sometimes all the way until driver intros, I’d still be thinking about what happened last week.”
It has taken some work, but Byron says that Monday night has become the transition into the next race. A similar characteristic of most athletes is their ability to compartmentalize. Even during difficult moments in his personal life, climbing into the car has often allowed Byron to narrow his focus solely to driving.
Working on the side has helped him further understand that ability rather than relying on it instinctively. One of Byron’s favorite places to practice some of the learned skills isn’t on the race track or in the gym. It’s on the green.
Byron has become an avid golfer and sees similarities between the sport and the mental challenge of racing.
“You have a bad shot or a bad break, or you’re not playing your best, and then you’re trying to reset to have another good shot,” Byron says. “There’s no blueprint for how to play well. You have to adapt and just try to do better the next shot.”
Golf has also become a consistent way for Byron to relax—even if that requires still keeping score. Before a recent race at Richmond, he played golf earlier in the day. There was initial worry the heat and activity might drain him before getting into the car.
He ended up finishing ninth.
“I thought the race went better because of it,” Byron says. “I thought I had a better result because I was more relaxed, and I did something to free my mind up.”
After years of figuring out how to be physically prepared for the rigors of being inside the race car, Byron has learned to do something similar mentally.
Trust what has already been built. Don’t force what doesn’t need forcing.
It’s a useful lesson whether you’re trying to control a Cup car at speed, staring down a difficult putt, or simply navigating the pressures of your own day-to-day responsibilities.
