Steve Bui, M.S.
Oh, glorious caffeine, one of man’s best friends!
For typical college students and other active individuals, it is a commonly required form of nourishment for any function before 10:00 AM. While we all know the basic immediate effects of caffeine (decreased fatigue, increased energy, and decreased appetite), it might be interesting to look at how that cup of coffee might affect other parts of your day. One area you may not have considered is how it will affect the daily workout session. Generally, exercise can be broken down into two categories: aerobic (longer, endurance exercises) or anaerobic (short term, strength exercises). Past and recent studies have shown that consuming from 2 to 4mg of caffeine/kg of body weight (approximately 1-3 cups of coffee depending on weight) can have significant benefits on aerobic exercise through its effects on fatigue and energy. In addition, studies have repeatedly shown that caffeine can also increase pain tolerance and increase power output during aerobic exercise as well. All of these effects can lead to increased quality and length of performance.
Decreased fatigue? Increased pain tolerance? These effects would seem to help any form of exercise! Unfortunately, studies have not been able to find definite results regarding caffeine and anaerobic exercise. Recent studies have shown inconsistencies in caffeine intake and strength performances, some showing increases in performance, while others show no change. It is proposed that the durations of most anaerobic exercise bouts are not long enough for the caffeine to affect performance. To complicate matters more, caffeine has been shown in previous studies to potentially inhibit muscle growth through certain metabolic pathways with caffeine then inhibiting growth hormone levels following resistance exercise. Since growth hormone has generally been associated with increases in muscle growth, a lower level could indicate caffeine might be unhelpful or even harmful in terms of strength training.
It’s still difficult to determine every single effect of caffeine; however, things are slowly becoming clearer. What might be a good policy for now? Maybe if you are tired and/or have some difficulty getting motivated to start that 20-30 minute run, reaching for that extra cup of coffee might actually be a great idea. It would allow you to run longer, faster, and be less tired overall. However, if you plan on trying to increase muscle growth by performing strength training exercises, that extra cup of coffee might potentially hurt your goals in the long run.
For Further Reading:
- Woolf K, Bidwell W, & Carlson A (2008). “Effect of caffeine as an ergogenic aid in anaerobic exercise.” International Journal of Sports Nutrition and Exercise Metabolism. (18) 412-429.
- Burke L (2008). “Caffeine and sports performance.” Applied Physiology & Nutrition Metabolism. (33) 1319-1334.