Although drinking one or two cups of coffee or tea or a caffeinated soft drink each day probably won't affect your energy levels, consuming too much caffeine may cause fatigue. Paradoxically, the same substance that you might use to increase your alertness in the morning can also leave you feeling drained. Caffeine interferes with sleep and may cause fluctuations in your energy that leave you more exhausted when the effects of the stimulant wear off, according to the National Sleep Foundation.
Chemical Effects
As a central nervous system stimulant, caffeine gives you a temporary sense of alertness and wakefulness. Caffeine can increase your heart and respiratory rate and boost your metabolism, giving you a burst of energy when you're dragging your feet. However, this burst may be followed by a greater sense of fatigue, or a "caffeine crash," according to the National Sleep Foundation. Consuming around 250 mg of caffeine per day -- the amount in three 8-oz. cups of coffee -- is probably safe, the National Sleep Foundation notes. However, too much caffeine can cause insomnia, especially if you consume caffeine within six hours of going to bed.
Sleep Disturbances
If you're drinking coffee or another caffeinated beverage in the mornings just to wake up, you may be losing sleep at night. When you're tired, caffeine can revive you by increasing your adrenaline production and suppressing chemicals in the brain that induce sleepiness. However, excessive use of caffeine can also lead to sleep disturbances. Over time, sleep loss can add up to a deficit, which may reduce your concentration, weaken your immune system and increase your risk of accidents.
Chronic Fatigue
If you have an ongoing lack of energy, you may be using caffeine to propel yourself through your daily activities. This stimulant may mask the symptoms of a more serious problem, like chronic fatigue syndrome, a cardiovascular condition, a hormonal imbalance or clinical depression. People with chronic fatigue syndrome, a condition that may be caused by a virus or an autoimmune disorder, may complain of anxiety, mood alterations and sleep disturbances, according to the University of Maryland Medical Center, or UMMC. These symptoms resemble the side effects of excessive caffeine use. The UMMC recommends that people with chronic fatigue syndrome avoid caffeine and other stimulants. Consult your health-care provider if you have persistent fatigue that isn't resolved by reducing caffeine or getting adequate rest.
Restoring Energy
If you've been drinking 500 to 700 mg or more of caffeine each day, you may be getting too much of this stimulant, Mayo Clinic notes. Edginess, anxiety and tremors are also side effects of excessive caffeine. To restore your energy, reduce caffeine in small increments so that you won't experience withdrawal symptoms, such as headaches, irritability or a further drop in energy. Watch for hidden sources of caffeine, like chocolate, cocoa, over-the-counter pain medications or energy drinks. When you get your energy from natural sources like sleep, healthy foods and regular physical activity, your fatigue may soon resolve.
References
- Mayo Clinic: Caffeine -- You May Like Caffeine's Effects, But How Much Is Too Much?
- National Sleep Foundation: Caffine and Sleep -- Information on Sleep Health and Safety
- University of Maryland Medical Center: Chronic Fatigue Syndrome
- MedlinePlus Medical Encyclopedia: Fatigue
- "Harvard Magazine"; Deep into Sleep; Craig Lambert; July-August 2005
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