Although caffeine acts to promote alertness and wakefulness in moderate amounts, too much caffeine can induce various health hazards. Studies have linked too much caffeine consumption to conditions such as high blood pressure , inconsistent heart rate , anxiety , panic disorders  , insomnia , and bladder instability . For women who has pre-existing bladder problems, consuming even a moderate amount of caffeine may lead to unstable bladder conditions .
Caffeine is associated with a risk of spontaneous abortions. Therefore, pregnant women are advised to limit their caffeine intake , . Caffeine is also known to pass into breast milk. Thus, it can cause symptoms such as fussiness and irritability in breastfed infants when breastfeeding mothers consume too much caffeine .
Prolonged consumption of caffeine in high doses—more than 500-600mg per day (equivalent to four to seven cups of coffee)—can result in a condition called caffeine dependence . Termination of caffeine intake in such people can result in caffeine withdrawal symptoms including headache, weakness, drowsiness, fatigue and decreased alertness . These symptoms can occur within 12 to 24 hours of withdrawal and can last for about a week.
Caffeine in moderate amounts can make you feel energised, but too much caffeine will cause a host of undesirable side effects. For some people, decaffeinated beverages such as decaf coffee and decaf tea can be a safer option.