Sunday, April 7, 2013

My last day of caffeine for a week!

Have you ever heard of a caffeine fast? I hadn't until I read about it in the Matt Fitzgerald book I mentioned in the last post. Fitzgerald points to a 2002 study showing that caffeine can boost performance in an endurance workout, but is more effective on non-users of caffeine than habitual caffeine users. Therefore, he surmises that to get the most out of caffeine during  a race, a habitual user should stop using caffeine for a period of time before a race.

But how long should you stop using caffeine to get the benefit? Unfortunately, according to Fitzgerald there hasn't been much research on this. He believes that a week of caffeine fasting is sufficient for moderate users of caffeine, but that two weeks might be needed for people who regularly consume several cups of coffee a day.

I switched to half-caf coffee about 15 years ago, and typically drink 2-3 cups a day, so maybe a maximum of 1.5 cups of fully-caffeinated coffee per day, plus a cup or two of black tea. I don't think that qualifies me as a heavy user, so I'm going to try fasting for a week before the Boston Marathon, which is a week from tomorrow (!).

Anecdotally, Fitzgerald says he regularly caffeine-fasts for a week before major races, then consumes about 3 mg of caffeine per kg of body weight 1 hour before the race, and he says he can tell that the caffeine is giving him a major lift.

I have never consumed caffeine before a race (other than the 20 mg or so that is in a pack of GU), so I decided to give it a try before today's workout, my last long-ish run before Boston (90 minutes at an easy pace, about 11 miles). I dragged myself out of bed an hour before the workout, and figured out that I should be taking about 250 mg of caffeine. The tablets I have are 200 mg, so I just took one of them, figuring I'd be eating several GUs during the run and those would also add to my total.

I definitely felt a lift during the run. I'd say I was downright perky, and since I've been fighting off the flu for the past couple weeks, it's been a long time since I could say that! That means all systems are go for caffeine-fasting and pre-race caffeination next week.

Speaking of Boston, it's now close enough to the race that we have some long-range weather forecasts. 8 days away, the current forecast is for a mostly cloudy day, with a high of 56 degrees and an overnight low of 41 the night before. That doesn't sound half bad, but as we learned at Rocket City, these things can change. I'm going to wait until 2 or 3 days out from the race before I'm confident in the weather forecast.

Details of today's workout are below.

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