The onset of fatigue frequently coincides with the onset of

The onset of fatigue coincides with mid-day most often. Your body discharges your brain's natural sleep chemical, melatonin, telling your body it's time to go to hit the hay between 2 and 4 in the afternoon. Michael J. Breus, PhD, a sleep expert, explains that the tiredness or fatigue you feel in the middle of the day is just like the tiredness you feel before bedtime at night. Mainly, because we wake up super early for work or for school, our body wants to go to bed in the afternoon because our usual clock is telling us to do so.