How can writers stay fit?

Recently, someone posted on social media that writing is an unhealthy activity - all that prolonged sitting. (I paraphrase). And they asked how other writers manage to incorporate activity into their daily work schedule.

My first response was dull, serious, but I thought it was accurate: 'I have a fitness tracker on my wrist and it buzzes when I've been sitting too long.'

Today I realised that the truth is slightly different. My tracker does not buzz very often and the reason is I drink prodigious amounts of tea, coffee, and also water (when I'm trying to be healthy). This requires regular stepping away from the laptop to prepare and collect said drinks, followed later by the inevitable need to visit the bathroom. It is quite amazing how many steps I accrue with this routine.