If you’re one of those attention-seekers yelling harder than Sharapova so the entire gym looks over to then notice you’re only Bench Pressing 150lb – please stop it. Different story if you’re going after a Squat PR. It’s a shame some dumb gym chains don’t make the difference by banning grunting as a rule.
Some “experts” claim that you’re not breathing properly if you grunt because the only way you can do it is by holding your breath and exhaling forcefully. Well hello Einstein, that’s the EXACT reason why grunting is the natural thing to do on a heavy Squat and Deadlift – try exhaling on the way up and tell me how your lower back likes that. Lifting heavy weights isn’t the same as running.
For maximal lower back safety, you should always Squat by taking a big breath, holding it on the way down, and then exhaling against your closed glotis on the way up. Yes your blood pressure will increase, but it will go back to normal once your set is done. How else do you think lifting weights improves your fitness?
More important is that the increased pressure in your stomach allows you to lift more weight, just like Squatting wearing a belt does. And this obviously means more muscle gains and fat loss on top of the increased lower back safety.
You’ll frankly have a hard time finding a top athlete who doesn’t grunt or yell when going all out. Tennis players like Rafael Nadal grunt, and there are studies showing it gives them an advantage. All Martial Artists grunt when kicking and punching. Even Schwarzennegger grunted back in his days at Gold’s gym.
If you train in a commercial gym you should control your grunting more than if you were lifting at home, just to not annoy the heck out of everybody. But when PR times come, let the hissing and grunting happen. The only people who won’t understand the grunting are the ones who aren’t lifting heavy enough.