A review of 10 studies (549 participants) with painful hip osteoarthritis concluded that the effect of exercise:
* improves hip pain
* improves physical function
Exercise types used in the studies varied from aerobic, strength, functional and flexibility exercises, and all showed some level of improvement in pain and function. My advice is to find something that you enjoy, and then build up the activity in a sensible and progressive manner.
Fransen, M., McConnell, S., Hernandez-Molina, G. and Reichenbach, S., 2014. Exercise for osteoarthritis of the hip. Cochrane Database of Systematic Reviews.