How Caffeine Can Hurt Your Potential for Success Rather than boost productivity, your cup of joe can slow you down.

By Lisa Evans Edited by Dan Bova

Opinions expressed by Entrepreneur contributors are their own.

If you're reading this in the morning, it's likely you're cradling a steaming cup of coffee in your hands. While putting in long hours at work causes many entrepreneurs to nurse the coffee pot, studies show caffeine has some serious side effects that can hinder your performance at work.

Push the cup of joe aside and decide whether you still want it when you finish reading this.

Interrupted sleep.

Caffeine can take a while to leave your system. If your first cup is at 8 a.m., 25 percent of caffeine will still be in your body at 8 pm. Any amount of caffeine left in your body will result in reduced REM sleep – the deep sleep your body needs to recharge. Research by Wayne State University published in the Journal of Clinical Sleep Medicine showed drinking coffee on the way home from work can impair sleep quality. Caffeine consumed six hours before bed reduced sleep by at least one hour.

Withdrawal symptoms.

Your afternoon slump may just be you coming off your caffeinated high. Research from Johns Hopkins Medical School suggests that energy jolt you get from your morning cup of coffee are the result of temporarily reversing symptoms of caffeine withdrawal. In fact, the researchers found caffeine-related performance improvements were non-existent without caffeine withdrawal, suggesting that cognitive performance decreases and mood worsens throughout the day when caffeine leaves the body and the only way to get back to feeling "normal" is to drink more caffeine.

Related: 15 Reasons You Will Live a Long Life

Impair your objectivity in decision-making.

Caffeine triggers the release of adrenaline – a hormone which triggers a fast response. This fight-or-flight mechanism is great if you're being chased by a bear, but not so great when you're responding to a curt email from an angry customer. When adrenaline is released, your brain is put into a hyper-aroused state, causing you to circumvent rational thinking in favour of a fast response.

Difficult to work with.

Caffeine can remove your ability to manage your emotions and may make you more irritable and anxious. Researchers at Carnegie Mellon University found that large doses of caffeine can raise your blood pressure, stimulate the heart, and produce rapid shallow breathing, which deprives the brain of the oxygen needed to keep your thinking calm and rational.

Stress.

If you find yourself stressed out all the time, your caffeine habit may be to blame. In a 2002 study by researchers at Duke University Medical Center, caffeine was shown to exaggerate stress levels in people who consume it every day. The effects of caffeine taken in the morning were shown to persist until bedtime and amplify stress consistently throughout the day.

Related: OMG Yes: A Smart Mattress Cover That Can Brew Your Morning Coffee

Lisa Evans is a health and lifestyle freelance journalist from Toronto.

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