The Cut spoke to Dr Jaclyn Tolentino, a primary care physician at Parsley Health, and Dr Richard Firshein, a general practitioner and insomnia specialist who runs the Firshein Center in Manhattan, about the most common culprits of exhaustion.

Hormone fluctuations can turn anyone into a nap machine, as anyone who’s ever had PMS knows. But chronic hormonal imbalances can make you sleepy and grumpy all month long. The good news is that doctors can test for the presence of most hormones, so they should be able to diagnose an imbalance if you have one; most are also largely treatable with medication and/or nutritional changes. One common issue is underproduction of estrogen or progesterone, which can cause tiredness, irritability, unpredictable periods, and night sweats.

via What Kind of Tired Are You?.