• Cooling shirts, featuring circulating cold fluids, have become essential for NASCAR drivers to manage extreme heat in cockpits.
• Jimmie Johnson and his crew chief Chad Knaus were early adopters, recognizing the advantage of maintaining driver comfort and reducing fatigue.
• The cooling shirts improve driver endurance, reduce heart rate, and are now considered a crucial piece of equipment despite adding weight to the car.

NASCAR drivers are employing cooling shirts to counteract the intense heat inside race car cockpits, which can reach up to 140 degrees. These shirts circulate cold fluids, offering a significant improvement over previous methods like ice packs and helmet hoses. The adoption of cooling shirts has grown, especially with the introduction of the Next Gen car in 2022, known for its increased heat. This technology helps drivers maintain focus and physical condition throughout long races, giving them a competitive edge.

• What: NASCAR drivers use cooling shirts that circulate cold fluids to regulate body temperature inside hot race car cockpits.
• Who: Key individuals include Jimmie Johnson, Chad Knaus, Joey Logano, Erik Jones, Michael McDowell, Shane van Gisbergen, Ross Chastain, Kyle Larson, Austin Dillon, Chris Buescher, and Tyler Reddick.
• When: Jimmie Johnson started using the cooling shirt around 2018 or 2019. Tyler Reddick began using one in 2021. The adoption increased with the Next Gen car introduction in 2022.
• Where: NASCAR race tracks across the United States.

The adoption of cooling shirts in NASCAR demonstrates a continuous effort to enhance driver performance and safety. The shirts mitigate the effects of extreme heat, reducing fatigue and improving focus, which can be critical in competitive racing. The weight penalty is a trade-off accepted by teams to ensure drivers remain in optimal condition. The evolution from ice packs to sophisticated cooling systems showcases the sport's commitment to leveraging technology for a competitive edge.

"It's like jumping in a pool on a hot summer day. It feels great. It's awesome."

"I think back years ago when we did ice packs in our suits and threw them out between stops. The endurance side, on a hot day, it's just a game changer."

"A lot of drivers use it. I think what it does for cooling the body is probably the most efficient thing that we have."

Cooling shirts, evolving from Jimmie Johnson's early adoption to widespread use, are now a mission-critical technology in NASCAR, significantly boosting driver comfort and endurance in extreme cockpit heat. These systems typically involve circulating chilled water through capillary tubing embedded within a specialized shirt, effectively absorbing heat from the driver. Despite the slight weight addition, the performance benefits, including improved focus, reaction time, and reduced dehydration, outweigh the drawbacks. Modern advancements include active cooling systems with battery-powered fans or pumps and the use of advanced materials like conductive polyethylene that conduct heat away from the skin. Beyond cooling shirts, drivers also benefit from helmet cooling systems that pump cool air into the helmet, hydration strategies, and physical fitness regimes to manage heat. Heat shields are also used to reduce cockpit temperatures and protect vital components. These comprehensive heat management strategies collectively ensure drivers can perform at their peak, pushing their limits while maintaining safety and minimizing heat-related performance decline.