Sleep Tracking: What's Worth Knowing, What to Ignore
A patient asked me last month whether she should buy an Apple Watch to "fix" her sleep. She is seventy-six. She had been waking three or four times a night for years. She was up to looking at watches that cost three hundred dollars. I told her what I'm going to tell you, which is that sleep tracking is occasionally useful and frequently a way to spend money on the appearance of doing something about a problem that requires a different solution.
Here is the honest version of what the technology can and cannot do.
What sleep tracking actually measures
A watch or phone that "tracks your sleep" is, almost without exception, doing one of two things. It is reading motion — the watch's accelerometer notices when you stop moving and assumes you fell asleep. Or it is reading motion plus heart rate — the watch combines the two to make a better guess about when you were sleeping and how deeply.
It is not measuring your brain. The "sleep stages" graph showing pretty colored bars for "REM" and "deep sleep" is an estimate based on heart rate and movement, and the estimate is often wrong. Sleep clinicians who have compared consumer trackers to clinical sleep studies find that the bedtime and wake-up times are usually accurate; the stage breakdown is largely guesswork.
What you can trust:
When you fell asleep, roughly. When you woke up, roughly. How many times you woke during the night.
What you can't trust:
The "deep sleep" or "REM sleep" percentages. The "sleep score" the app gives you each morning. The vague suggestion that your sleep quality is poor and you should somehow improve it.
What it's actually good for
One thing, mostly: confirming a pattern that you already suspect.
If you think you're going to bed at a different time every night, the data will confirm it. If you think you wake up at three AM every Tuesday, the data will confirm it. If your spouse says you snore for an hour after midnight and you don't remember, the data may corroborate it.
The tracker doesn't tell you anything you couldn't learn by paying attention. It does the paying-attention for you, which for some people is enough to motivate a small change — going to bed earlier on weeknights, or moving the bedroom TV out of the bedroom.
Phone-only sleep tracking
You can track sleep with just the phone, no watch needed. Both iPhone and Android offer a "Bedtime" mode and a sleep tracker built into the Health app or Google Fit.
iPhone: open Health → Browse → Sleep → set a sleep schedule. The phone will use the time you spend in bed-mode (no scrolling, no notifications, screen face-down) as an estimate. It's a rough estimate but it's free.
Android: open the Google Fit or Samsung Health app → Sleep → set a bedtime. Similar logic. Samsung phones include a more elaborate "Sleep Coaching" feature that adds a snoring-detection microphone analysis if you place the phone face-down on the bedside table.
The phone-on-the-bedside-table approach captures less detail than a watch. For most patients it's enough.
Watch-based tracking
If you already own an Apple Watch, Samsung Galaxy Watch, or a Fitbit, sleep tracking is on by default. Wear the watch to bed; the morning shows you a graph.
Battery life is the practical wrinkle. An Apple Watch worn 24/7 needs charging at some point in the day — most patients I know charge it for an hour in the morning while having coffee. Fitbits and some Samsungs last several days on a charge; easier to live with.
If you don't already own a watch, I would not buy one solely to track sleep. The data isn't reliable enough to justify the purchase if that's the only reason.
What to do if you're not sleeping well
This is the part that needs to be said clearly: poor sleep in older adults is common and is usually addressable through sleep hygiene, medication review, and — when those fail — a sleep study.
Sleep hygiene basics, which I review with most of my patients at some point:
Same wake time every day, including weekends. Bright light in the morning, ideally outdoors. No caffeine after noon. The bedroom is for sleeping; not for television, not for working, not for scrolling on the phone. A dark, cool room. A consistent winding-down routine in the hour before bed.
None of that is news. It is the boring answer that actually works.
Medication review matters more than people realize. Many common prescriptions interfere with sleep in older adults — diuretics that cause nighttime bathroom trips, antidepressants that affect REM, blood pressure medications timed wrong. Ask your prescriber or pharmacist whether the timing of your medications can be adjusted.
If the basics aren't working, a sleep study — either in a clinic or with a home unit your doctor can prescribe — is the real diagnostic tool. Sleep apnea, restless legs syndrome, and other conditions can be confirmed only by actual measurement, not by a consumer tracker.
My patient who wanted the watch
I asked her what she thought was waking her up. She said she didn't know. I asked whether she'd told her primary care doctor. She said she hadn't.
We spent twenty minutes talking through the basics. It turned out her diuretic was being taken at 7 PM, which meant she was up to use the bathroom at 1 AM, at 3 AM, and at 5 AM. Her doctor moved the diuretic to noon. Three weeks later she was sleeping through the night for the first time in years.
She did not buy the watch. I am, despite my profession, basically thrilled when somebody doesn't have to spend three hundred dollars to fix a problem.
The phone in your pocket can tell you a few things about your sleep. The conversation with your doctor will tell you many more. Have the conversation first.
Written by Linda Marsh, RN. Reviewed for clinical accuracy by Linda Marsh, RN (BSN, University of Iowa; 18 years registered-nurse experience). Editorially reviewed by David Chen. Last verified 19 June 2026. Clinical advice belongs with your prescriber.