I hit 40 not too long ago and I’m feeling it too. Arthritis in hips and hands flares up occasionally and makes life unpleasant. The only thing I’ve found that relaxing helps is managing inflammation through (a) reducing sugar intake, and (b) consuming spicy foods and healthy doses of cinnamon.
I put red pepper flakes or sriracha or sweet Thai chili sauce in anything that can bear it. Oddly enough, just eating cinnamon toast crunch cereal (store brand even) every morning has also helped immensely. When I run out and have to eat something else, I notice a definite uptick in arthritis symptoms.