Fatigue Cause no. 7: Caffeine Overload
Most people take caffeine to help them perk up. In moderation, caffeine does improve alertness and energy. However, too much caffeine can cause jitteriness, increased heart rate or palpitations, high blood pressure, anxiety, and insomnia. In addition, after caffeine wears off, users can 'crash' and feel fatigued.
If you drink a lot of coffee, tea, or cola that contains caffeine, or take medications with caffeine, you will need to gradually wean yourself off these drinks, supplements, or medications. You may experience withdrawal symptoms if you suddenly eliminate caffeine entirely, so start slowly. First, start drinking more water and fewer caffeinated beverages every day.