Im 34. I've used a permanent standing desk for 5 years, along with monitors at a proper height, an ErgoDox EZ keyboard, and a standing pad.

I havent experienced any issues so far, what issues could this create for me?

I find that if I sit I end up having lower back pain, my legs end up getting tingly after a while, and I just get sleepy if I'm too comfortable.

Do I actually need to force myself to sit? I'm moderately fit/athletic, standing has helped me with back pain and neck pains.