You stayed up late binge-watching Homeland. Then you woke up extra early to beat the boss to the office. Some days, there's no mystery as to why you need an extra shot of espresso (and if you can't sleep no matter what you try, check out these 10 sleep myths and real solutions for better shuteye.)
But sometimes, the root of your fatigue isn't so obvious, and everything from a hidden health issue to your gym habits could be to blame. "It's like asking a pediatrician why a baby is crying; the answer could be any number of things," says Tanvir Hussain, MD, a preventive cardiologist in Los Angeles.
A challenging puzzle, yes, but your fatigue is a mystery you can solve. Here are 7 reasons you could be dragging--and how to regain more energy than you ever remember having.
Healthy women who failed to replace a mere 1.5% of their water weight experienced mood swings and low energy levels, according to a 2012 study in The Journal of Nutrition. The