Too much can hurt work performance
As my friend found out during his presentation, too much caffeine can have a detrimental effect on performance. “Overconsumption of caffeine can cause anxiety, jitters and nervousness,” notes Harris. “It can also cause an inability to focus, digestive discomfort, insomnia and irritability.”
There are a lot of other sources for caffeine, such as tea, chocolate, sodas, energy drinks and even some non-prescription medications – all of which can increase the total amount of caffeine in the body.