One of the best way to relax not only the body but also for the mind is to do meditation.
The intention of sitting down in a comfortable pose, in a quite environment, in private or in group, with a soft lighting, cool refreshing air or breeze and even with a soothing slow music set at the background with a relaxed mind can quickly lure you into a state of meditation.
Counting from 1 to 9 while taking a slow breathing taking in, and agin when you expire outward count slowly from 1 to 9 quietly in your mind. Repeat this over multiple cycles. As you do this process, think of nothing but just focus on your slow state of breathing. A simple technique like this can help to slows down the heart beat and the anxious mind quickly. Once you are experienced, may may be even able to do it successfully in many other unlikely venue and timing . A slowed state of heart beat will be beneficial to the health
There are meditation sole intended to relax, other for the health purpose, some are meant for spiritual application.
For knee joint arthritis and other body parts and joint pain treatment without drugs.