The majority of adults worldwide start their day with caffeine, usually in the form of coffee or tea. Caffeine is generally considered safe for those who tolerate it well, but the pervasive stimulant may do more than simply provide a jolt of energy in the morning or help you make it through your afternoon meetings — it may boost your workouts, too. Caffeine has been shown to benefit performance when consumed before endurance exercise and short-term exercise lasting at least five minutes.
Aside from performance, what is caffeine’s net effect on the body during exercise? A team of researchers from the University of Granada aimed to find out.
In a new study published in The Journal of the International Society of Sports Nutrition, the scientists looked at whether caffeine increases fat oxidation (aka “fat-burning”) during exercise. They enlisted a group of men to complete a series of exercise tests in the morning and afternoon, with some participants receiving 3 milligrams of caffeine per kilogram of body weight 30 minutes before the test, and others receiving a placebo.
After the four-week study, the data showed the participants who ingested the caffeine burned more fat during exercise than those who ingested the placebo. This occurred independent of the time of day, but the effects were more significant during afternoon exercise than morning exercise.
Per the researchers: “The findings of this study suggest that the combination of acute caffeine intake and aerobic exercise performed at moderate intensity in the afternoon provides the optimal scenario for people seeking to increase fat-burning during physical exercise.”
HOW TO APPLY THE FINDINGS
These are easy instructions to follow. For the best results, consume caffeine of your choice about 30 minutes before exercise. If you want to follow the study parameters closely, a 150-pound person would need about 200 milligrams of caffeine or roughly the amount in 2 cups of brewed coffee. (Most guidelines suggest limiting your intake to 400 milligrams per day, but individual tolerances vary.)
Before you start chugging coffee or otherwise ingesting caffeine prior to each workout, know that some research has actually shown caffeine to have potentially harmful side effects when used before or during exercise. According to a 2019 study, combining caffeine and high-intensity exercise may increase the risk of developing blood clots, so you might consider targeting your caffeine intake before lower or medium-intensity workouts.
THE BOTTOM LINE
Caffeine is safe for most people, however, and those who already use caffeinated products without negative consequences should be safe to continue. But, if you have cardiovascular risk factors, you may want to take it easy with the caffeine. As with most things, when in doubt, ask your doctor.
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