Not to mention that regularly hearing a beep over the PA system would be supremely annoying and distracting.

@DavidK Completely agree, added a note into teh answer itself.

@DavidK, not a regular annoying beep like the ones when the building is on a fire drill. Please do not think of it in such extreme scenario. I don't think people get annoyed by notification messages from the phone.

@Prasanna How do you know people don't get annoyed from random phone notifications? I do, at my workplace, while working. At times, even the noise from having the phone in vibration mode, placed on a solid surface can cause distractions.

@Prasanna It depends on how often, how loud, and what type of noise they would be. Even a quiet beep every 10 minutes would drive me crazy. A quiet chime every hour on the hour could maybe be tolerable. If you want some external reminder for people to sit up, you'd be better off associating it with something that already exists in your office: every time you hear a phone ring, or when you check your email, or when you take a drink of coffee/water.

How about picking a regular audio cue that's already present in the environment that you can't do anything about and people have to deal with already?

The premise of your answer is flawed. In many countries the employer has a responsibility to ensure safe work practices. The employer can be held financially or criminally responsible for injuries or deaths at work. So it isn't a matter of "choice". For example, in the US, there are regulations requiring workers place locks on equipment they can be shocked or crushed by. Many employers enforce this regulation by immediately firing any employee who fails to lock equipment. Similarly, a friend works at home for a major company and is required to have regular ergonomist visits, no visit no pay.

@user71659 there is a difference between being safe vs being correct / healthy. That said, if this was meant to be a rule, it can go in a rulebook and be part of official policy (like, filling up the timesheet to get the pay), but if this is running as a campaign, (like, a yoga awareness camp), then obviously it's not part of the policy and need not be treated as such. I took what is mentioned in the question, not some assumption.

@SouravGhosh In the US at least, repetitive stress injuries, carpal tunnel syndrome, etc. are considered a safety issue, is regulated by the government, and has brought significant financial liability to companies. So it is a safety issue, and not merely "correct".

@SouravGhosh I don't see any country tag period. My link shows liability for RSI applies to US and EU at least.

@DavidK Actually, a regular beep (quiet or not) would achieve nothing (except to amuse visitors to the office) because everyone would quickly learn to tune it out. I have an old mechanical clock in my house that chimes every 15 minutes, and strikes the hours. I personally never hear it - unless it stops, in which case something in my brain prompts me to look at it to check the time. Go figure....

@SouravGhosh I don't know how it is in your country, but, here, in Portugal, out packs have really ... unappealing ... images of the consequences of smoking. Though you may want to add it to your example, to show that even with the dangers and consequences right in front of them, people do decide to do it anyway.

@user71659 that to the best of my knowledge just means, just as in Europe, that employers must provide their employees with the means to have a healthy working environment, not that they must go around and watch over them like a mother hen watches over her chicks for compliance.

@alephzero suffering from anxiety disorder, I cannot "tune out" any environmental sound, and as a result those beeps would be extremely annoying and if frequent enough become a serious health hazard to me (symptoms of anxiety attacks attacks look like a mix of a heart attack and a stroke).

@Prasanna Why do you think in exams phones aren't allowed? It's not about cheating, because that would limit it to just "smart phones"; and certainly wouldn't be an issue before they existed... no, it's because a phone ringing in an exam is VERY distracting for everyone. Honestly, I can easily imagine HR having to take action if you implement this for multiple reasons.

If this was voluntary, and maybe lights flashing instead of buzzing it would be pretty cool, and I actually would like to have something like this installed on my desk. Carpal tunnel is soo painfull, and i would appreciate if company helped me guard against it, of course only if voluntary.

@jwenting Incorrect. Look up "duty of care", which is a very broad responsibility. The employer has a duty of care to its employees, which means they must take actions to guard against foreseeable risks. If the employer finds unhealthy work practices, the have a duty of care to take necessary actions to correct them. As I said, in many situations, policies requiring firings for unsafe actions are common.

@jwenting UK: "Your employer has a legal duty to try to prevent work-related RSI and ensure anyone who already has the condition doesn't get any worse."

@user71659 that doesn't include harassing them at their work site if they lax their posture behind their computer for a bit. It includes making sure they have the means to do their job safely and that proper equipment is used (no different from enforcing construction workers wear their hard hats for example).