Burn the candle at both ends

To exhaust yourself by working too hard or trying to do too much, especially by staying up late and getting up early. Implies unsustainable behavior that will lead to burnout.

Refers to the practice of lighting both ends of a candle to get more light, which makes it burn twice as fast and last half as long. The metaphorical use appeared in English by the 1600s, warning against unsustainable expenditure of energy or resources.