Incredibly, the average American is more likely to grab a cup of joe than a glass of water, with research suggesting that 66% of the population drinks coffee every day, at an average rate of 3.1 cups. It follows that we want to know more about this extremely popular drink and whether it is good for our health or not. However, if you've read about caffeine (a natural stimulant found in coffee beans), you know that opinions vary wildly, with some quarters praising it for its performance-enhancing potential and others denigrating it with claims that caffeine causes dehydration . Ahead of National Coffee Day on October 1st.
M&F spoke to Dr. Neil Clarke, Associate Professor of Sport Science from the Center for Sport, Exercise and Life Sciences at Coventry University, England, to separate fact from fiction.
Caffeine and its relationship to performance
“Caffeine is commonly taken by professional and amateur athletes to enable improved performance in a variety of activities such as intermittent exercise like soccer and racquet sports like badminton. It's also used for cardio exercises like running and cycling, as well as resistance exercises like weightlifting," says Clarke. “A recent meta-analysis reported that caffeine produces a small but evident improvement in endurance when taken in moderate doses of 3 to 6 mg/kg body mass, as well as an increase in mean power output (3%) and time trial completion Time (2%)."
Additionally, in tennis and golf, caffeine intake has been shown to increase shot accuracy and overall player success, possibly due to improved reaction time and mental alertness. "However, the evidence for ingesting caffeine during sprint training is less compelling," says Clarke. “But it still shows that sprints lasting up to 3 minutes show limited improvement with caffeine consumption. And in events lasting about 10 seconds, ingestion has been shown to improve peak power, speed and strength.”
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Caffeine and its relationship to cognition
"In addition to caffeine's well-known ergogenic effects on physical performance, caffeine intake may also improve cognitive performance, particularly in people who are sleep deprived," says Dr. Clarke. "For example, caffeine doses of 1 and 5 mg/kg body mass ameliorated performance declines during repeated rugby passing practice in elite rugby players after sleep restriction. In virtually all capacity studies using caffeine, the “assessed perceived exertion” values are lower compared to the placebo groups. In sports like tennis and golf, ingestion has been shown to increase shot speed and accuracy, as well as overall game success, possibly due to improved reaction time and mental alertness.”
Caffeine and dosage
The Mayo Clinic says daily dosages totaling up to 400 mg appear safe for most healthy adults. That's about 4 cups of coffee a day. In terms of performance, however, a dose in excess of 300mg per day may hinder rather than help your performance. "Possibly due to increased muscle tremors and postural fluctuations," says Clarke. "Low doses of caffeine, less than 3 mg caffeine/kg body mass, are ergogenic and are associated with few, if any, side effects, although this area has been less well studied.
"Larger doses of caffeine above 9 mg/kg body mass do not appear to increase the performance benefit and rather increase the risk of negative side effects including nausea, anxiety, insomnia and agitation. "Consequently, most of the previous research on caffeine typically focuses on ingestion of 3 to 8 mg/kg body mass."
Caffeine and its relationship to fat loss
"Studies in the late 1970s reported that caffeine ingestion may increase the mobilization of fatty acids, which, when released from adipose tissue, are transported to muscle and potentially used for fuel," says Clarke.
The relationship between caffeine and fat loss is still being studied today, and a recent meta-analysis concluded that ingesting a moderate dose of caffeine before exercise can increase fat utilization during submaximal aerobic exercise when performed after a period of fasting. "For example, a pre-workout intake of 3 mg/kg body mass increased fat utilization from approximately 19 grams per hour with a placebo up to 25 grams for the caffeine-ingested group when both groups performed 1 hour of submaximal cycling." says Dr. Clarke. "So it appears that caffeine can boost fat oxidation when taken before a workout.
“However, there are a few points to consider. It's important to note that the effects may have been enhanced because this exercise is performed without breakfast, when fat oxidation is naturally higher and carbohydrates negate the effectiveness of caffeine. Additionally, caffeine's ability to enhance fat oxidation during exercise tends to be higher in sedentary or untrained individuals than in trained and recreational athletes. Finally, although caffeine intake may increase fat oxidation, it is important to note that weight loss occurs only when one is in negative energy balance, where energy expended exceeds caloric intake.”
Caffeine and its relationship to dehydration
There has long been a belief among bro scientists that drinking coffee may have a diuretic effect, but recent research shows this to be false. "The traditional form of caffeine administration in research and sport has been to take pills or capsules with liquid," says Dr. Clarke. “However, there is increasing evidence that caffeine administered in alternative forms such as coffee, when consumed in moderation, contributes to daily fluid requirements and does not adversely affect fluid balance, particularly during exercise. So drinking coffee can actually help you stay hydrated.”
Is Caffeine Safe?
"The European Food Safety and Food Safety Authority concluded that "single doses of caffeine up to 200 mg" (approximately 3 mg/kg body mass) from all sources do not raise safety concerns for the general adult population. Moderate coffee consumption can be defined as 3 to 5 cups a day,” says Clarke.
Drinking coffee has a wide range of benefits that can improve performance from a physical standpoint. These include but are not limited to; improved muscle endurance, movement speed and muscle strength. "Performance may also be enhanced due to the release of endorphins, which dull the sensation of pain and the evaluation of perceived exertion during exercise, reducing the perception of exertion," says Clarke. "In addition, factors such as improved reaction time, cognition and mood are also likely to have a positive impact on performance."
One last thought about coffee
It's well-documented that there are significant differences in caffeine content, both in terms of concentration and per serving, between coffees,” Clarke. "For example, the caffeine content of raw arabica coffee is lower than that of robusta." Then there's a chance that ingredients added to your cup of joe could interfere with the benefits. "One final point about coffee is that the effect of milk on the biological effectiveness of caffeine is currently unknown," says Clarke.
So when you reach for your next Starbucks, you might want to ditch the cream and syrup and stay in a calorie deficit to make the most of caffeine's potential to burn fat and improve physical and cognitive performance.