The short answer
When long sleep still leaves you tired, look beyond duration: (1) whether you woke during the night, (2) whether your daily timing has drifted, (3) whether you feel rested on waking, (4) whether habits or health have changed, (5) whether strong daytime sleepiness or snoring has persisted. If symptoms continue and affect your life, speak to a doctor.
Key points
- "Time in bed" and "time asleep" are different
- How rested you feel on waking matters as much as how long you slept
- Review night waking, drifting daily timing, stress and alcohol as well
- Strong sleepiness, reported snoring or apnoea, and persistent poor days are reasons to seek advice
1. You are actually waking in the night
Eight hours in bed can be far less asleep once you subtract time falling asleep and time awake in the night. Short awakenings often are not remembered. Look at bedtime, wake time and awakenings, not only the total.
That said, Apple Watch sleep stages and awakenings are estimates. Do not treat one night's chart as a diagnosis; read it alongside weeks of trend and your own sense of things.
2. Your body clock and your schedule have drifted apart
When weekday and weekend timing differ a lot, sleeping long on a day off can leave something like jet lag behind. Japan's Ministry of Health, Labour and Welfare sleep guide notes that sleep cannot be banked on days off and that this can produce social jet lag.
Alongside duration, check how much your wake time moves from day to day.
3. You do not feel rested
Japan's Ministry of Health, Labour and Welfare emphasises the sense of being rested by sleep, not just its length. That sense involves daytime stress, eating close to bedtime, lack of movement, the bedroom environment and alcohol, as well as short sleep.
Recording "how rested I feel" on the same scale each morning, before you look at any numbers, makes it easier to notice when it and your sleep duration disagree.
4. Something other than sleep is involved
Tiredness is not always a sleep problem. Infection, pain, low mood, chronic conditions and medication can all contribute. Rather than settling on a cause from app data, record when it started, how strong it is and how it affects your days.
5. A sleep disorder may be hidden
Even with enough hours, conditions such as obstructive sleep apnoea can fragment the night and leave daytime sleepiness and a poor sense of rest. Habitual snoring, someone noticing you stop breathing, morning headaches and strong daytime sleepiness are all worth taking to a clinician.
If you only record for seven days
- Bedtime and wake time
- Estimated sleep duration and waking in the night
- How rested you feel on waking, on a five-point scale
- The trend in resting heart rate and HRV
- Alcohol, exercise, late meals, and changes in how you feel
References
- Sleep Guide for Health Promotion 2023 (Japanese) — 厚生労働省
- Sleep measures (Japanese) — 厚生労働省
- Insomnia (Japanese) — 国立精神・神経医療研究センター
- Track your sleep with Apple Watch and use Sleep on iPhone — Apple サポート