Heavy Periods Making You Tired?

Heavy periods aren’t just inconvenient or messy—they can be absolutely exhausting. While it might feel like you’re losing gallons, the typical amount of blood loss during a period is actually much smaller than most people think. On average, most women lose 20 to 80 milliliters of blood per cycle—that’s about 1 to 5 tablespoons total for the entire period. Let me repeat that: total. Not per day. The National Institutes of Health actually compares it to one and a half shot glasses. (Yes, that’s the official visual. Cheers?) What causes heavy periods?