You never think it's going to happen to you.
Then suddenly you're middle-aged and you find yourself grunting when you pick up something from the floor or groaning when you get out of the chair.
Why do we do this? Is it a sign that we're ageing fast? Or is it just one of those things that come with the middle years, like reading glasses, greying hair and "dad jokes"?
As far as I could find, there have been no specific studies to explain why otherwise healthy older people grunt or groan with the physical effort of everyday activities.
But noises relating to physical exertion are common in a range of ages and activities, as anyone who has watched cricket, boxing or in particular, tennis, will know. Think Serena Williams and Rafael Nadal.
What does this mean for everyday activities?
What all this means for grunting during everyday activities is unclear. Clearly, athletes' grunts during fast, ballistic movements are different to the noises we make when exercising in a gym or when we get up from a chair.
Perhaps we are more likely to make such noises if we are tired or fatigued. And if someone thinks a task is going to be hard, they might be more likely to grunt or vocalise.
So that's when they're most likely holding their breath, to try to provide momentum and stability for the task ahead, then releasing it.
While there has been no research on this phenomenon, as far as I can tell, grunting with physical exertion does seem to be habitual.
These noises are most likely learned behaviours that we copy from friends and relatives and start doing without realising it. So, you can choose not to groan the next time you get off the couch.