If you suffer from arthritis, like me, and are really feeling it this global cooling winter, then the natural instinct is to wrap up in cotton wool, and reduce exercise. That is a mistake, as this article explains:
http://blueheronhealthnews.com/site/2018/06/29/new-arthritis-paradox-discovered/?tt=newsletter&it=IT_V04
“A team of researchers noticed that astronauts who spent a lot of time in space had an increased risk of osteoarthritis. Interestingly, in space there is no gravity and therefore no strain on their joints. The researchers placed meniscus cells in a bioreactor built by NASA that simulated space conditions. After just three weeks, they observed genetic changes in the cells that normally occur when arthritis begins to take hold. From this, they concluded that microgravity caused genes responsible for healthy meniscus tissue to switch off while simultaneously causing genes that led to the breakdown of this tissue to switch on. The harmful effects of microgravity on weight-bearing joints might result from the fact that they are precisely engineered to withstand tension and large biomechanical forces. When this tension and force in the form of body weight is removed in space, the joints cannot perform the functions for which they exist, thus triggering their degradation.”
This weightless situation was functionally equivalent to not exercising. Consequently the key is to still keep doing moderate, sensible exercise for arthritis. It is like keeping a rusty hinge in motion, to get some sort of movement rather than letting it rust up completely:
https://arthritisaustralia.com.au/managing-arthritis/living-with-arthritis/physical-activity-and-exercise/