Record-breaking heat has plagued most of the country so far this week and in my current location of Houston, TX it has been around 100°F each day. Now, feel free to call me weak and not tough, but lately my workouts have been suffering and I am going to go ahead and blame it on the oppressive heat (and the fact that I am still recovering from a back injury). My pace has slowed, my legs have ached, and the thought of hitching a ride back home from strangers has even crossed my mind. However, I refuse to allow the temperature to force me to run indoors, since that to me, is too boring mentally.
Luckily, while reading some journal articles earlier this week (yes, I admit I am nerd) I came across some information that caffeine may help reduce leg muscle pain associated with endurance exercise in hot environments. For some time the scientific literature has noted that caffeine intake, either before or during endurance exercise, will enhance endurance performance (read abstracts here, here, and here). However, this study out of the University of Connecticut (read the abstract here) examined how caffeine intake affected pain and perceived exertion during prolonged cycling in both cool (12°C, which is about 54ºF) and hot (33ºC, which is about 91ºF) environments. What the researchers found is that although exercise in the heat results in increased muscle pain compared to the cooler environment, that ingestion of caffeine will help reduce this pain in the hot environment.
Participants in this study consumed 3 mg of caffeine per kilogram of body weight one hour prior to their cycle trial and then the same amount after 45 minutes of cycling. To determine how many mg of caffeine that would be for you simply take your body weight in pounds and divide by 2.2 and then multiply that number by 3 mg. Example: 120 lbs./2.2 = 54.5 kg; 54.5 kg x 3 mg/kg = 163 mg of caffeine. To put that amount in to perspective, 1 shot of espresso contains between 50-110 mg of caffeine, and several sports food companies sell products with caffeine in them.
With this article in mind, it seems that until I acclimate to the hot and humid environment I am living in, the people at my local coffee shop will be seeing me a lot more for the next few weeks! If you have found yourself shying away from your typical walks, runs, bike rides, etc lately because of the heat, try consuming the above recommended dose of caffeine an hour before your workout and see if that helps keep you going and reduces the increased muscle pain you may have experienced recently. As with any sports nutrition advice remember to first try it during a training session and not during competition so that you can see how your body responds. Have a great day, get out there, and beat the heat!
Note: A common misconception is that caffeine intake results in dehydration, which could be very dangerous while exercising in extreme heat. However, the diuretic effect of caffeine is typically only present in people who do not consume caffeine regularly, and furthermore is primarily only apparent during rest, not exercise. Several scientific studies have demonstrated that there is no dehydrating effect from caffeine consumption during endurance exercise.