Are You Tired All the Time?

Culprit: Your Adrenal Glands

They’re responsible for secreting the fight-or-flight hormones adrenaline and cortisol, which surge as a response to stress—whether the prehistoric-days type, like being chased by a tiger, or the modern-day version, like financial worries or your mother-in-law. But when you’re feeling stressed all the time, those glands may become overworked and can tire out—a condition commonly called adrenal fatigue, says Keenan. The inability to secrete enough cortisol during the day can cause energy dips, then spikes at night that can interfere with restful sleep.

To give your adrenal glands a chance to recharge, Keenan recommends meditation, which she thinks of as parking the body in neutral. “Meditation has the effect of slowing down the production of cortisol for a while,” she says. Try sitting quietly and clearing your mind for at least five minutes a day. Vitamins B5 and C have also been shown to support adrenal function, says Jacob Teitelbaum, the Kona, Hawaii–based medical director of the Fibromyalgia & Fatigue Centers and the author of From Fatigued to Fantastic! ($17, amazon.com). He recommends getting at least 50 milligrams of B5 and 500 milligrams of C daily. Other stress-reduction techniques work well, too. “Exercise is particularly effective,” says Park.

Culprit: What You Drink and Eat

Caffeine can be a lifesaver on sleepy mornings, but too much may be problematic, since it can act as a diuretic. “And dehydration can cause fatigue,” says Bonnie Taub-Dix, a registered dietitian in New York City. Aim for at least eight cups of fluids a day, more if you eat a lot of high-fiber foods, which absorb water.

Food sensitivities and their side effects can also bring on fatigue. “Lactose intolerance, for example, can cause diarrhea, which can result in dehydration,” says Taub-Dix. Teitelbaum notes that a diet high in processed foods can aggravate food sensitivities and lead to fatigue (one such sensitivity is the inability to metabolize gluten, which is found in many processed foods). An internist or a registered dietitian can determine if you have a food intolerance.