What is the fatigue score? The fatigue score is not a subjective feeling — it is calculated from the gap between your actual sleep and your target sleep over recent nights. It rises when you consistently sleep less than needed, and gradually falls as your sleep improves.
Fatigue level reference: • ≤ 0: Energized — recent sleep has been sufficient • 0–2: Normal — minor deficit • 2–5: Mild fatigue — try going to bed a little earlier tonight • 5–8: Moderate fatigue — focus and efficiency are likely affected • > 8: Severe fatigue — seriously reassess your sleep schedule
Does staying up late make it worse? Yes. Even if you sleep long enough in total hours, falling asleep outside your biological nighttime window is less restorative. Going to bed late while already sleep-deprived slows your recovery.
How to bring the score down: • Aim to meet your target sleep duration each night • Try to fall asleep before midnight to keep your body clock regular • No need to over-sleep in one night — a few consecutive nights of good sleep will gradually bring the score back to normal