If you have to be indoors, I would suggest standing and having the windows wide-open. Especially if you are working at a computer, consider the keyboard and mouse as an unhealthy solution. This is where the power of AI will become interesting. Imagine a world where we can type what we think without having to raise a finger. Using voice dictation is the best current solution.
I think the more time you spend indoors, the more unhealthy you become whether physically or mentally. The air conditioner is not natural. Perhaps keeping the window open is the best option. I suppose for the winter having a heater is necessary, but wearing a warm jacket and being outside is better.