

Dude. If have enough remaining brainpower to ogle women at the gym and enough blood flow to spare to give you a boner I can assure you you’re barely working out.
Learn to focus.
That said, being topless (for both men and women) in a gym is gross. Don’t leave sweat everywhere. The question is for running outside…
If you’re actually working out you don’t have blood flow to spare to have a boner…
And if as you say you can have a boner looking at sand it and don’t control it it seems to me like having topless women around shouldn’t influence that much the odds you get a boner.