Monthly Archives: June 2012

Is there such a thing as too much coffee?

I didn’t used to think so either…

This is what I would look forward to every morning! This is what made me want to get out of my warm cozy bed.  I love the smell of coffee, the taste of coffee, and that little kick it gives me when I wake up (which is becoming more needed the older I get).  However, I decided a few days ago that I needed to give up my daily caffeine addiction.

So, last week I was feeling awful… I mean I literally didn’t want to move… it was tough getting out of bed, I had headaches, and after work all I wanted to do was nap and not get off the couch.   I made it to the gym but barely had a good work out – and afterwards I was shaking, weak, and light-headed.   Of course my remedy for this was to have even more coffee – in addition to the 4 or 5 cups I was having every morning.   I wasn’t realizing this was making my situation worse.  The last straw was Sunday night, when I had the brilliant idea of drinking the iced coffee I had left in the refrigerator earlier that morning.  After I drank it, I had one of the worst headaches ever – and then I asked myself “what would happen if I just didn’t have coffee tomorrow?”

The next day, not having any coffee, I felt better than I had in weeks! I had more energy and felt more focused and my muscles didn’t feel weak like they had the past few weeks.  So I decided to do some searching on PubMed for any studies linking coffee and fatigue.  I already knew the two were linked because of a study I performed in my own lab.  Super high doses of caffeine actually have the opposite effect than low doses.   In the zebrafish that I study, high caffeine caused the larvae to swim at much slower speeds than the ones treated with low doses of caffeine.

But I also found a very interesting case study that completely described the symptoms I was having.  In a report in Clinical medicine insights: case reports from 2007, there was a woman admitted to the hospital that developed rapid muscle weakness and general fatigue.   After several blood tests, the doctors diagnosed her with hypokalemia (which is a severe loss of potassium in the body).  Apparently, she was drinking large amounts of coffee daily which subsequently leached the potassium out of her body because coffee is a diuretic.

Potassium is essential for proper nerve firing and normal muscle cell functions.  When blood potassium levels become too low muscles become fatigued (with spasms), there is presentation of abnormal heart rhythms and palpitations, and paralysis can occur with severely low levels of potassium.   After reading this article, I decided to keep going on my no coffee (or other caffeinated products) experiment.   Going off caffeine completely isn’t the most pleasant experience.  I was definitely having withdrawal symptoms (headaches, tiredness), but overall I felt 100x better than I did last week.   I actually had two great workouts finally and didn’t feel like I was going to pass out when I finished.   I may eventually add coffee back into my diet, but for now I am feeling great without it.

While this is a documented clinical case report, there still are many other factors that could have contributed to the patient’s symptoms.  While coffee-induced hypokalemia exists, it isn’t widely reported.  This is a great reminder that even the good things in life need to be appreciated in moderation.


1) Yutaka, T. Coffee-induced HypokalaemiaClin Med Insights Case Rep. 2010; 3: 9–13.

2) Richendrfer H, Pelkowski SD, Colwill RM, Creton R. On the edge: pharmacological evidence for anxiety-related behavior in zebrafish larvae.  Behav Brain Res. 2012 Mar 1;228(1):99-106. Epub 2011 Dec 6.