Gym grunting ... there's a level that is OK. The occasional slip of a grunt or noise when lifting heavy weight is OK. The constant grunt with every move... that's a bit much and yes everyone is looking and judging or trying not to laugh.
I've personally let some sounds slip out before... those usually come from exhaustion or frustration. Then there was this one time I was at the gym and on a treadmill next to one of my girlfriends. Her then now husband and my friend was over in the lifting area. Over my headphones I could hear a constant intense grunt. Popped the earphones out and realized it was my friend and her husband to be. I looked at her and just said... handle that lol.
Grunting though is in fact good for boosting performance. Bad for your blood pressure! So if you have bad blood pressure maybe you should just leave this practice alone! And if you like to grunt...don't be obnoxiously loud (Newsweek)
Check out some grunting pranks ...these had me laughing!