I'm quite animated and like to enthuse my pupils so sitting still isn't really something I do when I'm teaching lol
Are talking about teaching a class or 1:1 tuition?
You seem to imply that you can't enthuse pupils by sitting down?
I would disagree with this assumption - every situation is different and it may suit your particular situation to stand up and be animated but people respond differently to different approaches
There are definitely some advantages to sitting down with someone whilst teaching so it could be good for your body/health to mix things up a little
I've played a LP for the past 15 years so I'm well used to the weight now too
Being "used to the weight" is something completely different to the weight causing you damage!
You were probably "used" to the loud noise a band made - how is the ringing in the ears?
(I can say this as I am in exactly the same boat!!!! - oh to be young again!!!)
I wouldn't dream of telling you how to teach but what you are currently doing appears to be affecting your health so something needs to change??
Doing the same thing and expecting a different result is a sign of madness you know
As long as the ringing in your ears doesn't turn in to voices I think you will be fine though!!!