First, when your body's temperature drops, it signals to your brain that it's time to sleep. This happens because our internal "body clock" is influenced by changes in temperature. Studies have shown that people exposed to Cooler temperatures before bedtime fall asleep faster and sleep more soundly. Second, cooler temperatures help your body regulate melatonin production. Melatonin is a hormone that makes us feel sleepy and is produced by our bodies in response to darkness. So if you're looking to maximize the hormone's effects, keeping your room cool can help.