As is true with humans, your cat’s joints are likely to stiffen over time which limits his ability to climb stairs, jump, and run. Though some cats escape physical symptoms for longer than others, veterinary researchers estimate that 90% of cats over the age of 10 are affected by arthritis to some degree. Feline arthritis is a degenerative disease, so it will only get worse over time. There is no cure, unfortunately, but symptoms can be managed with medication, physical therapy, and lifestyle changes.