Dr. Valham and others published the results of an interesting study in the April edition of the Sleep Journal. He noted that some of his patients told him they snore less when their bedroom is at a colder temperature. He then designed an experiment to test whether obstructive sleep apnea (OSA) would lessen in a colder environment as well.
He studied 40 patients by having them do 3 sleep studies, each at 61 degrees F, 69 degrees F, and 75 degrees F, but in random order. The results showed that the OSA severity was significantly higher at 61 degrees versus 75 degrees. But, the patients slept 31 minutes longer and slept significantly better in the 61 degree room. Also, those in the coldest room reported the most alertness the next morning! These results are confusing as you might think that the more severe the OSA, the lower the sleep quality and less alert someone would be the next day.
However, this just points to the fact that OSA severity does not determine completely how someone feels the next day. I have patients with very severe OSA who do not feel tired at all and tell me they sleep well each night. I also have patients who barely meet criteria for OSA who can not sleep well and have a difficult time staying awake during the daytime.
Back to this study - the researchers did not measure snoring to see if that had reduced with the cooler room temperatures. That data would be interesting to see. Also, the researchers can not explain why the OSA would be more severe as the room gets cooler. Finally, even though the subjects slept better, there was no difference in the proportion of the different sleep stages at the different room temperatures.
The implications from this study is that room temperature can help you sleep longer, sleep better, and improve your morning alertness - these results may help insomniacs improve their sleep quality.