Rule
First, rule out obvious lifestyle bottlenecks (sleep timing, movement, nutrition). If fatigue is new, severe, or progressive, consider medical evaluation early.
| Pattern | Common drivers |
|---|---|
| Morning fatigue | sleep debt, poor sleep quality, sleep apnea, late light/screens |
| Afternoon crash | under-fueling, high added sugar, sleepiness debt, low movement |
| “Wired tired” | chronic stress, anxiety, excess caffeine, late work |
| Exercise feels harder than usual | sleep debt, illness, low calories/protein, overtraining |
Red flags
Seek urgent care for chest pain, shortness of breath at rest, fainting, or a sudden major change in exercise tolerance.
Seek evaluation for persistent fatigue with unintentional weight loss, fevers/night sweats, or severe depression.