Bats and opossums do not get arthritis like other animals, and the reason all has to do with how they sleep. They sleep upside down which is an old yogic technique — a twist on a healthy sleeping position. Sleeping upside down with the hips above the head and heart is fantastic for the body as it bring more blood flow to the brain, neck, glands, and heart while taking compression off the spine and de-adrenalizing the system. We produce precursors to adrenalin: epinephrine and androstenedione in order to stand upright; when we invert, these are not required and we de-stress or de-adrenalize.
The brain needs blood while one sleeps. It is the highest altitude part of the body all day long, and it craves greater access to blood and oxygen while the body is at rest. You may even want to ditch the pillow that can elevate your head above your body, not allowing you to sleep deeply. Pillows may be causing neck and jaw issues while keeping the brain elevated and, therefore, keeping the body slightly adrenalized. It is best to rest and (if possible) sleep with the legs and hips above the head and heart whenever possible.
The ancient yogis considered gravity a toxin to the body. That is because gravity brings everything down to the ground—eventually 6 feet under! Many poses in yoga are all about getting the head and heart down below the hips thus essentially flipping gravity around and making them beneficial. These poses include shoulder stand, headstand, waterfall, downward dog, etc. If we take a look at the most commonly applied inverted yoga positions or asanas, we can see that the head and heart are in a downward position. This allows for better blood flow and relieves the spine of compression.
Inversions are essentially anti-aging positions that elongate the spine. Arthritis is an age-related condition that the yogis sought to prevent. The asanas or yogi positions can help us to stay young as long as we get upside down.
Take a look at this incredible video from David Avocado Wolfe and see for yourself why sleeping inverted is great for the body and mind!