Take a mystery to bed
If you're looking for a way to improve your sleep, an old fashioned paper book and mellow yellow lamp turn out to be the perfect combination!
Here's the science behind that statement - Insomnia
But why choose a mystery?
Won't the mental stimulation keep you awake?
What about other genres?
Danger is a fact of life. We can die of an infection, get killed in a car wreck, be shot by an enemy, or forced out of our homes by financial problems.
To be able to face and address these challenges, we must allow the brain to rest. But our brains have a default setting that takes over when we are not focused on anything in particular. This is why you start to worry when you turn out the light and close your eyes.
Mysteries pull us in and focus our minds on the story puzzle. We go over the plot points as we sleep. It is even possible to wake up with the solution in our heads. By focusing on the fictional problem, we allow our brains "time off" from the real-world problems that we must face during the day.
Other genres can be absorbing and entertaining, but none require the concentration a mystery does. Romance, in particular, can also introduce an element of angst that can short-circuit the brain's rest cycle.
And there is another benefit. With a mystery, you know there will be a resolution, a solution, probably a satisfying bad-guy-never-wins type of outcome. And that can prime your brain for success in the day that follows. Call it a self-fulfilling prophecy. If the hero can do it, so can you!