NFL teams and Olympic athletes are adding an unexpected item to their winter recovery protocols: polyester felt sauna hats. The New England Patriots recently partnered with RecoveryFlex to develop sweat-wicking hats that accelerate post-game muscle repair.

“Sauna sessions boost circulation, but unprotected scalps overheat quickly,” says team physio Dr. Rachel Nguyen. “Polyester’s quick-dry properties let players stay in longer—critical during -20°C winter training.”

The hats’ moisture management also aids hydration tracking. Embedded sensors (compatible with polyester’s smooth texture) monitor sweat electrolyte levels, syncing data to fitness apps. “We’ve reduced cramping incidents by 18% since adopting these,” says a hockey coach.

Consumer versions retail at $35, with brands like SportSauna offering team logos. While purists argue wool is “more natural,” athletes prioritize function. “I’d look ridiculous in a wool hat, but this? Pure performance,” laughs NBA star Damian Lillard.