Q: Is it OK to drink coffee before exercise?
Absolutely. In fact, having some java prior to training can be beneficial. Caffeine acts on the sympathetic nervous system to increase production of the fight-or-flight hormones called catecholamines (i.e., epinephrine and norepinephrine). Among their diverse functions, catecholamines mobilize fatty acids from adipocytes (i.e., fat cells), allowing them to be utilized for energy. Since exercise increases caloric expenditure, the body can make immediate use of these fatty acids to fuel your muscles. Translation: Caffeine expedites the loss of body fat during a workout, helping you to get leaner, faster.
Caffeine also has been shown to have a positive effect on exercise performance. With an abundance of fat in circulation, your body is less reliant on glycogen, glucose, and amino acids for energy, thereby delaying muscular fatigue. And by sparing glucose, your brain functions better (glucose is the primary fuel for your brain), pumping you up to train harder, longer. These benefits have been shown to be present in activities lasting as little as 60 seconds or as long as two hours.
And of course, caffeine can give you that extra “kick” during training. Its stimulant-like effects serve to increase heart rate and skeletal muscle readiness. Studies have shown that ratings of perceived exertion are reduced after caffeine consumption, meaning exercise doesn’t seem as difficult. This translates into a boost in alertness and energy levels, with performance improvements exceeding 11 percent over placebo.
Caffeine is quickly absorbed into the body, and its effects peak at one hour or so after ingestion. Ergogenic benefits are seen with the consumption of 300 milligrams of caffeine, equating to about two brewed cups of coffee. Realize, though, that caffeine can produce unwanted side effects. Some people are sensitive to caffeine intake and should refrain from its use. It’s explicitly contraindicated for those with certain medical conditions and during pregnancy. What’s more, caffeine can impair sleep. It has a half-life (the time required for the quantity consumed to decay to half of its initial value) of about six hours, meaning that if you ingest 300 milligrams at 6:00 p.m., you’ll still have 150 grams in your body by midnight. This not only can have an effect on your ability to get to sleep, but also the quality of the sleep, as well. Also, caffeine can have mild diuretic effects, so make sure to drink plenty of water during training.
A potentially better option is to consume a couple of cups of herbal green tea directly before exercise, especially if fat loss is your goal. In addition to containing caffeine, green tea also contains compounds called catechins that serve to further increase metabolism. Catechins inhibit an enzyme called catechol-O-methyl-transferase, which is responsible for degrading the catecholamine norepinephrine, a potent hormone that promotes the oxidation of body fat. In combination, caffeine and catechins act synergistically to enhance energy expenditure beyond what is achieved by caffeine alone.