Coffee and Dehydration: Fact or Myth?

I have to admit, I am a dedicated coffee drinker.  I'm not going to say I'm addicted to the stuff...but I'm not going to say I'm not either.  The funny thing about my coffee drinking is that it all started because one day I just decided, "I'm going to be a coffee drinker."  I had never enjoyed it before, and when I started about 4 years ago I didn't even know how to make a good pot of coffee, let alone know the difference between good and bad coffee.  But that's all changed over time, and now I can't imagine life without it.

My Coffee Stash

While I can't say I practice an incredibly healthy diet, I try to do things that I know are healthy.  My favorite snack food is Cheez-Its, and I've switched to organic cheese crackers.  My breakfast most mornings normally includes a banana and cereal and, of course, coffee.

When I first started drinking coffee I decided I wanted to make it as healthy as possible.  And from what I had read, it seemed that straight black coffee in moderation actually has health benefits, including lowering the risk of heart disease, Parkinson's and some forms of diabetes, and serving as an antioxidant.  The key here is "black coffee."  So very early on I started making it my goal to drink my coffee black all the time.  I started with adding flavored creamer, and over time slowly started using less and less, until after about a year I could enjoy my coffee black...which I still do to this day.  I mean, just in terms of pure calories, black coffee has 2 calories, but adding cream and sugar can put that number well over 100 and beyond.

But I digress.  The real reason I'm writing is not about the health benefits of coffee, but instead how it can affect your running.  For years I've been told coffee is a diuretic and will flush your system of important fluids and electrolytes due to how much it makes you pee.  And if my trips to the bathroom after drinking coffee are any indicator, I would say that assessment is spot on.  However, I was reading an article last week that took a different tone one the apparent detrimental effects of coffee on hydration.

The study (which can be found at this link), while VERY limited in scope (and funded in part by European coffee companies), studied the effects of normal coffee consumption on hydration.  Now I want to start by saying I don't 100% agree with this study, mainly because of its small sample size...but it's definitely worth a quick view.  While the study may be a bit suspect, you can't deny what they found. Here's a quick overview:

They studied 50 men over a period of 3 days, some drinking 4 mugs of coffee at regular intervals, some drinking 4 mugs of water at regular intervals.  Each man was given a standard diet to follow during the 3 day test period so their fluid and calorie intake was controlled.  The mens' urine and body weight were then tested on the fourth day for fluid levels and some other scientific nonsense I don't understand.  They were then given a 10-day "wash-out" period in which they were to live life normally and consume their normal diet.  After this, they switched roles.  If the first time they drank the coffee at regular intervals, this time they drank water, and vice-verso.  The studies showed virtually no difference in the mens' fluid levels during their coffee days and their water days. 

I think the key here is "moderate" coffee intake.  I normally try to follow this rule, especially on work days.  However, lately as a teacher I've found it difficult.  I'm at the end of what has turned into a week off school due to weather, holidays and professional development.  When I am off school I drink probably twice as much coffee than on a normal day.  My normal consumption on a school day is 1 cup in the morning with breakfast or on the way to work (depending on how many times I hit the Snooze button).  I then drink a second cup around 11:30 at the end of my planning period.  That's it.  I spend the rest of the day hydrating, preparing for my evening run.

But in my 7 days off I have spent most morning sitting around, reading, writing or watching TV, all while drinking coffee.  Before this, I had only had a Keurig single serve coffee maker at home, but I got the idea to buy a large coffee maker and coffee grinder just because I wanted them.  Now, the programmable coffee maker is a wonder of science.  I was trying to get a bit of extra sleep this morning, but I eventually woke up when I smelled the coffee brewing, and I've been drinking from that pot of coffee ever since. 

But what I'm getting at is that coffee and caffeine, in moderation, can actually be good for you.  The old idea of 8x8 oz. glasses of water a day is not a wise decision.  If all you drink is water, then you'll just pee most of it out.  You need to get different fluids in your body, and coffee can be one of those fluids.  You will retain some of the water in the coffee.  Other options are healthy juices (low in sugar) and electrolyte drinks (again, low in sugar).  The fruits and vegetables you eat throughout the day are also loaded with water so you can get your hydration from those as well.

The key is, don't just assume if you are drinking only water all day that you are getting enough fluids.  Too much water can actually be bad for you.  Find the right balance.  Still drink plenty of water, but diversify.  Coffee can be good for you in moderation.  Vegetables will hydrate you so eat your water.  Other healthy fluids can also hydrate you.  Just make sure you are sufficiently hydrated before (and after) your run.  Thanks for reading.