Water lubricates our joints. The cartilage tissues found at the ends of long bones & between the vertebrae of the spine hold a lot of water, which serves as a lubricant during the movement of the joint. When the cartilage is will hydrated, the two opposing surfaces glide freely, & friction damage is minimal. If the cartilage is dehydrated, the rate of "abrasive" damage is increased, resulting in joint deterioration & increased pain.