There was a time when gyms, steam rooms and saunas were ideal meeting places for men to meet for sex - quite a lot of it was pretty public. These venues were well known within the gay community and people went there anonymously to meet others for sex. It was at times as seedy and vile as you can imagine and at time great hot sex - no strings attached. It is not something that anyone should be doing at say their local Planet Fitness or other modern spa built for fitness. At one 'health club' I used to use the running joke was the weights were rusted to the floor from disuse. At that time meeting other gay men was actually illegal in some places. It was illegal in NYC for men to dance with men and women to dance with women. If you were found to be in a 'notorious place' (i.e. a gay bar) you could be arrested and taken to jail just for being there, fully clothed minding your own business.
There was a whole subculture to it, men rented small rooms for sex and left their doors open to advertise their availability or cruised the steam rooms and showers. A wink, a nod, a caress a knowing look and bang, you were hooking up either on the spot or in a more private area. There were clubs for every strata pf person -the leather scene had its own place, young guys had theirs, fetish folks were somewhere else. The venues set out food, and had entertainment - Bette Midler used to sing at "The Continental Baths" in New York, with Barry Manilow playing the piano. True story. Gives a whole new meaning to "I write the songs' and 'Mandy."
Some similar venues still exist today but this is completely different from mainstream health clubs. Given the availability of applications like Grinder and Tinder people don't need to go to the baths as they were called - but some linger on. I myself have not been to a gay bath house or gym for decades. All of the ones I had cards for are gone. I do go to the gym most days, but not for sex.
Employees who worked in the gay sex bath houses and gyms were often gay and knew what they were signing up for. One guy who worked for a while at the DC Olympic Baths used to get the guys excited when he closed the glass enclosed showers to clean them because he worked naked, except for rubber boots. Another guy lived for a while at the Baths and worked there too. I remember one evening he was getting ready for work, brushing his teeth after he showered, wearing a towel at the sink. Another customer came up and started rubbing his butt and the guy did not bat an eye, saying, "I can't now, I'm on my way yo work."
It was a different era and it was what it was. I have few regrets because after I found these places It was a community of sorts - you saw the same guys, people usually respected limits - it was sexy, exciting and dangerous all at the same time.