Feeling exhausted when you wake up, feeling as if 8 or 10 hours of sleep a night is insufficient or being unable to function all day without a nap can all be signs of thyroid problems. (With hyperthyroidism, you may also have nighttime insomnia that leaves you exhausted during the day.) Fatigue symptoms are usually mild at first before increasing in intensity.
The key identifier of thyroid-related fatigue is that is remains unrelieved, no matter how much you sleep or nap during the day. This fatigue inhibits patients’ ability to remain productive in day-to-day life, and it’s often what causes them to see a doctor for a diagnosis.