Sports dietitian Lauren Antonucci answers a question about coffee on race day and addresses the myth that it can cause dehydration.
Q: I love my morning cup of coffee. Should I cut it out on race morning to stay hydrated and improve my performance?
A: Every time I give a sports nutrition talk to a group or team, this question is asked. I too look forward to my morning coffee for a host of reasons—taste, warmth, morning ritual, and a wake-up “boost.” Should we cut it out on race morning? Thankfully, the answer is no!
First, let’s dispel the dehydration myth. When consumed regularly, and at moderate amounts (see below), caffeinated coffee does not lead to dehydration or excessive urine loss, and therefore may be counted toward total fluid needs (phew!).
Now what about caffeine’s performance benefits? Dozens of studies have shown performance benefits of caffeine consumption in athletes, including lower RPE (rate of perceived exertion), improved endurance performance and clearer concentration.
However, there are downsides. Caffeine can act as a G.I. stimulant, and while most triathletes are happy to have pre-race toilet time, excessive caffeine consumption (from pre-race coffee and/or caffeinated sports products during a race) can lead to dreaded effects such as diarrhea or jitteriness.
What to do? My recommendation is to start by cutting your usual caffeine intake in half on race morning. Less than your usual caffeine dose, coupled with normal pre-race excitement, should lead to desired alertness and an overall good race situation. Of course, each individual responds differently, so practice in early-season races and adjust this (and all pre- and during race fueling) until you find what works best for you.
How much coffee is OK?
A moderate amount is considered 3–6mg per kilogram of body weight. To convert to pounds, multiply your weight in pounds by 0.45 to find your weight in kilograms. That means for a 120-pound triathlete, you could drink around 160–320 mg of caffeine. A 160-pound triathlete could drink 220–440mg. For reference, one 8oz cup of coffee averages 100–150mg of caffeine.
Clinical nutritionist and certified sports dietitian Lauren Antonucci is the owner/director of Nutrition Energy in New York City.