Al fresco workouts in 90-degree heat are such a bad idea that the parent of Boston Sports Clubs is welcoming walk-ins for free indoor workouts during heat waves through Aug. 31.
Through that date, “all club locations will open their doors to the public for free workouts every time the temperature hits 90 degrees or above,’’ the Town Sports International said in a press release. One other condition: A person must be 18 or older.
Town Sports International operates 25 Boston Sports Clubs in this market. All told, it has about 160 clubs in places like New York, Philadelphia, and Washington, D.C., as well as Boston.
‘‘When the temperature reaches over 90 degrees, it is not safe for people to work up a sweat outside,’’ Chris Ruta, a company vice president, said in a statement. ‘‘We are opening our doors to allow people to enjoy the A/C and stay safe while working out in the summer heat.’’
A company spokeswoman said Town Sports International has made similar free workout offer during previous heat waves. It took a similar approach after last year’s Hurricane Sandy.
Asked if the company saw a rise in gym memberships after making such offers, she replied that such trend-lines aren’t something that the company tracks.
“The decision to join a gym is complex,’’ she said.
According to the company’s website, there are Boston Sports Clubs in such locations as Davis Square, Government Center, Beacon Hill, and South Station.