They found that high doses of caffeine, around 70 uM, increased muscle power by six percent when the mice performed either low or high intensity exercise. This means that, at least in mice, high doses of caffeine improves muscle performance – at high and low levels of exercise.
Most previous studies looking at caffeine and sports performance have focused on the effects caffeine has on the brain. By acting as a stimulant, it sharpens focus and reduces fatigue during exercise. This study shows that high doses of caffeine may also boost muscle power by another mechanism – by acting directly on skeletal muscle tissue.
Even though caffeine increased muscle power during both low and high intensity exercise, it only increased endurance for lower intensity exercises such as long distance running, jogging, cycling, and walking. It actually decreased stamina and endurance during high intensity exercise such as sprinting and weight lifting. This is consistent with previous studies.
Before guzzling caffeinated coffee prior to your next workout, keep in mind that 70 uM of caffeine is a hefty dose of caffeine – although the researchers in this study pointed out that some heavy coffee drinkers have blood caffeine concentrations as high as 50 uM. This dose of caffeine could only be easily achieved using a concentrated liquid or tablet – and this could be dangerous for people with heart or blood pressure problems. It’s not clear whether lower levels of caffeine have the same muscle boosting effects as these ultra high doses.
The bottom line? High doses of caffeine boosts muscle performance during exercise of any type, but the risks aren’t worth it unless you’re an athlete using caffeine under medical supervision.
References:
Medical News Today. “High Doses Of Caffeine Directly Increase Muscle Power And Endurance During Relatively Low-Intensity Activity”