Mid 40s and try to hike 4.5km daily (we have a nice trail near our house) and longer on the weekends, up to about 12km is ok on the same trail system. If you can find a nearby trail you enjoy with good elevation change that’s IMO the best way to improve.

I highly suggest using Organic Maps on mobile for finding nearby trails, though I usually then switch to Apple or Google Maps satellite view for visual confirmation the area seems ok before striking out. I was shocked how many trails there were around me hidden in plain sight, hopefully that’s the same in your area.