Sci’s not going to lie, she’s a HUGE fan of caffeine
And I remembered only too well many of the things that ERV has said previously about how she uses caffeine before her workouts, to give her the extra boost and improve her workout. So when I saw this abstract on the effects of caffeine on resistance training in humans…well obviously I had to check it out.
Bui et al. “The Effects of Habitual Caffeine Intake on Lead Body Mass and Strength Performance During 12-Weeks of Resistance Exercise Training” Texas A&M, presented at Experimental Biology, 2011.
(Via I can has cheezeburger)
Scientists have known for a while that caffeine can increase the productivity of your cardio and endurance workouts (there’s a reason all the gels and stuff you can buy now have caffeine in them). Taking caffeine before a cardio workout may increase your power and endurance, generally making you go faster and longer.
But that’s only one TYPE of exercise. What about resistance workouts and strength training? Believe it or not, the effects aren’t fully known, so Bui et al. set out to study the effects of caffeine on resistance exercise.
They got 58 sedentary adults (about 60% female), all over the age of 60, and had them began 12 weeks of basic strength training. Participants also received 2 weeks of nutrition education before the study started, and were then required to report 4 days of food intake each week. Before and after the training, their strength was tested and differences in strength were recorded.
Post study, participants were separated into three caffeine groups: low, medium, and high based on caffeine intake. The low caffeine group consumed an average of less than 150 mg of caffeine per day, or about 1.5 cups of coffee or less. The medium caffeine group consumed about 150-300 mg of caffeine or 2-3 cups of coffee, while the highest group consumed more than 300 mg of caffeine, or 3 cups of coffee per day.
Unfortunately, they couldn’t really uncover any significant effects of caffeine, but it looked a little like caffeine might have the OPPOSITE effect on resistance training then what it does on endurance training: possibly decreasing gains. While this seems rather odd compared to the endurance and cardio results that we know, it’s not so surprising. Caffeine has been shown to increase levels of cortisol, and decrease growth hormones which may both decrease muscle growth. Furthermore, it may be involved in inhibiting some other pathways of the muscle growth as well.
Of course this study is just a preliminary study. These were all older, previously sedentary adults, with unknown caffeine intake histories (before the study). Furthermore, their caffeine sensitivity levels were unknown as well. The good news is that Bui et al. are starting more studies to really investigate the effects of caffeine on resistance training. This time they will be using RATS, who don’t need nutrition training, can’t skip workout sessions, and who you can make sure have consistent caffeine intakes in each group. So it’s possible that the results, while not significant in this study, will possibly be more significant in the study with the rats, which is something I can’t wait to see. All we know is that although we have been using caffeine for hundreds of years, there are still many questions about it that need to be clarified.
Ballou et al. (2008) – Rapamycin and mTOR kinase inhibitors
Foukas et al. (2002) - Direct Effects of Caffeine and theophylline on p110 and other phosphoinositide 3kinases
Wu & Lin (2010) - Caffeine attenuates acute growth hormone response to a single bout of resistance exercise