Brushing your teeth before bed is a common part of nighttime routines. However, making it the very last thing you do before bed could be the reason why you can't fall asleep within a healthy time frame (around 10-20 minutes is average).In fact, experts say you shouldn't brush your teeth within less than one hour of going to bed if you want to fall asleep quickly and easily. "It sends a signal to your body that it's not actually time to go to sleep, so we produce more wake-promoting hormones, such as cortisol, to stay awake," explain sleep researcher Hannah Shore, Head of Sleep at MattressOnline.Here Shore explains what happens to your hormones and your energy levels when you brush your teeth right before bed, and how that impacts your ability to fall asleep. She also reveals the three other key activities to avoid right before bed to sleep better.Key takeaways : At a glanceAccording to sleep researcher Hannah Shore, brushing your teeth right before bed forces you to stay active when your body is naturally winding down. This in turn suppresses melatonin, the sleep regulating hormone.Bright LED bathroom lights and overstimulating mint-flavored toothpastes enhances alertness and can cause temporary insomnia.Other activities Shore recommends you avoid close to bedtime include eating heavy meals and exercising vigorously. These activities raise your body temperature, which in turn makes it biologically harder to fall asleep.Why you shouldn't brush your teeth right before bed