The studies were first done on mice. They were sleep deprived and then tested how their tails reacted to hot water. The findings concluded that lack of sleep reduced the pain threshold of the mice. Thus they reacted to a lesser amount of pain compared to mice which had a good sleep.
Not surprisingly, healthy humans showed a similar trend when they were tested for pain after disturbing their sleep. In one study, healthy volunteers, who had no sleep disorders and were pain free were tested on a sleep routine that involved a 8 hour, 4 hour, and sleep with REM sleep disturbance. The following day, they were tested using a radiant heat stimulus and measuring the time taken to withdraw the finger.
The results showed that loss of 4 hours sleep made the volunteers to respond to pain 25 percent faster. When the REM sleep was disturbed the response time was 32 percent faster. This indicated that it is the REM sleep that is more responsible for pain perception the following day. Similar studies have confirmed that it is the loss of REM sleep that makes us perceive pain in an exaggerated manner.
What are the implications? REM sleep is more concentrated at the latter part of our sleep. So when you stay up late and have to get up early, your REM sleep suffers more than other sleep stages. This increase in pain sensitivity may not be visible in our daily work. But for people who have undergone surgery, the increased sensitivity to pain makes a huge difference. It has been suggested that opioid medications used post surgery to relieve pain, can actually interfere with REM sleep. So when your REM sleep is knocked down by medications, it can backfire by increase the pain sensation. The exaggerated pain response will also make any painful experience, seem worse.
So the next time you need a pain-killer, use mother nature’s best pain treatment – REM sleep.
