An example of a typical sleep diary (provided by the National Sleep Foundation) can be found below:
There might be newfangled sleep gadgets and apps that offer the same option; it's up to you if you would prefer to keep a digital diary as opposed to an old-school one.
The purpose of a sleep diary is to offer your physician clues about your sleep habits and schedule. This information is far more important than many patients believe. Being as honest in one's responses for each of the questions offers insight that the sleep doctor cannot discern on their own; even a technologist watching a patient sleep overnight in the lab may not be able to pick up on these insights because they are multitasking for 12 hours at a stretch with each night at the lab.
Sleep "tracking" is not a "better mousetrap"As far as "sleep tracking" with your smartphone goes, the information you collect really isn't going to be any more or less accurate than what you keep with a print diary unless your app or gadget has a function which legitimately reads and records electroencephalograms (or EEG). Currently, there aren't any mainstream FDA-approved products that do this.
Much of the data on these phone sleep tracking apps may be useful for noticing trends (in wake up times during the night, for instance), but they are no substitute for an actual sleep test. They may, in fact, give you a highly inaccurate portrait of your sleep patterns because they really can't discern the difference between sleep and wake.
Caveat: any app that suggests you can track sleep "stages" is making a false claim because it can only do so with corroboration from an EEG measurement.
Do your homework: filling out your sleep diaryIf you have been asked to keep a sleep diary prior to your visit to the clinic for a sleep test, please take it seriously and do your homework. The information is critical to a correct diagnosis, and your health relies on sharing it with medical professionals in order to find resolutions to your sleep problems.
If you don't have a sleep test coming up, but have concerns about your sleep habits, you can also keep a sleep diary just for your own information. Your awareness of the data you collect can help you decide whether you might need to see a doctor or if you should take a proactive stance on your own habits and sleep hygiene. You might be surprised what you learn about yourself just by keeping an eye on your sleep!