When you’re dead tired, caffeine can be an instant antidote, pepping you up and keeping you alert at crucial moments.
A mild stimulant of the central nervous system, caffeine also revs up the heart, relaxes smooth muscles, increases stomach secretions, and has a diuretic effect.
On the positive side of the ledger, caffeine can increase levels of neurotransmitters (brain chemicals) like norepinephrine, acetylcholine, dopamine, serotonin, epinephrine, and glutamate; these changes in turn increase alertness, attention, concentration, mood, and memory abilities and decrease fatigue. Caffeine can also give you a slight boost in metabolic rate, and regular caffeine consumption has been found to reduce the risks of Parkinson’s disease and type 2 diabetes.
But caffeine becomes an energy-sapping substance when it’s relied upon too heavily. It may increase blood pressure and cortisol secretion, cause shaky hands and anxiety, and contribute to insomnia and a delayed onset of sleep. Plus, if you’re a java junkie who relies on caffeine (from coffee drinks, energy drinks, energy bars, and “natural” diet pills) to keep you going, the continuous rise and fall in stimulating effects is often accompanied by mild dehydration and symptoms of withdrawal—a bad combination.
It’s a pattern that can lead to crashing and burning in the energy department. Believe me—I’ve been there! During my second year of medical school, when I was drinking a pot of coffee a day, I had built up such an extreme tolerance to caffeine that within an hour or two of having it, I would experience symptoms of withdrawal, including fatigue, difficulty concentrating, and headaches.
When you get an energy boost after drinking coffee, it’s not real energy—it’s the effect of caffeine, a drug—and it’s short-lived. When the effects of caffeine wear off and your body realizes it doesn’t have a true source of energy, you’ll probably feel exhausted and maybe hungry. At that point, you might decide you need more caffeine, or you might choose to eat but end up overeating because you’re in such a state of energy depletion. Either way, an unhealthy cycle begins again—one that can lead to further energy drain.
The take-home message: Use caffeine wisely, and pay attention to your total intake. Many women are fine with having coffee in the morning and then using caffeine occasionally as a temporary stimulant to increase alertness before an important meeting or before driving a long distance. If you find that you need additional pick-me-ups throughout the day, it’s time to look at other energy-boosting measures (perhaps taking a brisk walk or a short nap, inhaling a whiff of a stimulating scent like peppermint, or splashing your face with cold water). Having more caffeine isn’t the answer.