A racing mind cycling through tomorrow's unfinished tasks ranks among the most common reasons people struggle to fall asleep, and a genuinely elegant piece of research from Baylor University offers a simple, well tested countermeasure.
The Study Behind the Recommendation
Researchers led by Michael Scullin recruited 57 healthy young adults for an overnight sleep laboratory study, randomly assigning half the group to spend five minutes writing a detailed to-do list for the coming days, while the other half spent the same five minutes writing about tasks they had already completed. Using overnight polysomnography, the gold standard method for measuring sleep, the researchers found that participants who wrote to-do lists fell asleep in about 16 minutes on average, compared with roughly 25 minutes for those who wrote about completed tasks, a genuinely meaningful nine minute difference.
Why Writing Down Tomorrow Works Better Than Reviewing Today
The researchers proposed two competing explanations before the study: that writing about the future might increase worry about unfinished business, or that writing a to-do list might help offload those thoughts and reduce worry instead. The results supported the offloading explanation clearly, consistent with earlier research finding that poor sleepers' pre-sleep thinking tends to center on planning, problem-solving and anticipating future events, precisely the mental territory a written to-do list addresses directly.
Specificity Genuinely Matters
The study found a meaningful relationship between how detailed and specific a person's to-do list was and how quickly they fell asleep, with more specific lists associated with faster sleep onset. This lines up with a well known psychological phenomenon called the Zeigarnik effect, where incomplete tasks remain mentally active until they are either finished or clearly planned out, suggesting a vague mental note is considerably less effective at quieting the mind than a genuinely detailed written plan.
Putting the Technique Into Practice
- Keep a dedicated notebook and pen at your bedside specifically for this purpose, making the habit as frictionless as possible
- Set a timer for five minutes and write specifically about tasks for tomorrow and the coming days, rather than reflecting on what already happened
- Be as specific as possible, writing "call the dentist to reschedule" rather than a vague "health stuff," since detail appears to strengthen the effect
- Make this the very last activity before turning off the lights, since the original study restricted all technology and other activities immediately afterward
A Reasonable Caveat
The original study involved healthy young adults without diagnosed sleep disorders, so while the technique offers a genuinely promising, low effort tool worth trying, it may prove more or less effective for people managing chronic insomnia or significant anxiety, populations the initial research left largely unexamined.
The takeaway: A five minute, specific to-do list written just before turning off the lights offers a genuinely evidence backed way to offload the mental clutter that often delays sleep, with a well designed sleep laboratory study confirming real, measurable benefit.