By Shannan Lynch, PhD, CSCS, HFS, CISSNThis article presents new research that challenges previous notions about caffeine; shedding light on some of its benefits and helping us better understand how caffeine affects us.Caffeine is the world’s most consumed stimulant — and I’m among those who partake of it. Openly, I admit, I drank two cups by the time I finished this, which is completely okay.
We’ve Been Consuming Caffeine Since the Stone AgeSince the Stone Age people have been grinding up various leaves and barks, steeping the grounds in hot water as a flavored beverage and stimulant. Modern science has unraveled the mysteries of this ancient compound, exposing its toxicities, side effects and contraindications. Consequently, science and the media have successfully conceived a smear campaign against caffeine.
Why Caffeine Seems to Wake Us UpCaffeine stimulates the central nervous systems (CNS) by competing with adenosine—a molecule that promotes sleepiness (among many other actions)—except caffeine has the opposite effect. Caffeine binds to the adenosine receptors, but instead of suppressing the CNS, it stimulates it.Caffeine is a drug, by definition, but it’s found inside many of the foods we consume such as coffee beans, tea, chocolate, soft drinks, energy drinks and even some over-the-counter pain relievers. Thus, it’s very hard to avoid caffeine especially since approximately 90% of adults in the world consume it in some form.When used as supplement to ward off drowsiness and increase alertness and mental focus, caffeine can be a very effective and overused compound. The effects can be received as quickly as 10 minutes depending on the source (for example, chewing gum is an effective way to deliver caffeine) and last as long as 4-10 hours.
What Else Caffeine Can Do for YouNot only is caffeine a CNS stimulant, but one of caffeine’s metabolites accelerates metabolism by increasing the breakdown of fat, explaining why most diet pills contain caffeine.Additionally, caffeine has been shown to improve coordination and other athletic indices, therefore the combined metabolic and CNS effects have categorized caffeine as an ergogenic aid.The National Collegiate Athletic Association (NCAA) sets restrictions on caffeine consumption; urine concentrations greater than 15 mcg/ml result in a failed test. In an adult male, this is about three 12 fl oz cups of strong coffee or about three servings of some energy drinks (which is a lot to drink before a game).However, the major concern is extreme doses of caffeine from pills and other high-end ergogenic compounds. Until 2004, caffeine was on the World Anti-Doping Agency banned list. The ban was lifted as a result of widespread use and not enough current research to back “unsafe” claims, and let’s not forget the long list of emerging beverage company sponsors that use caffeine in their products.
The Good News About CaffeineWhen consumed in low to moderate doses, there are many positives to report about caffeine, especially for enhancing sports and occupational performance that require physical activity and acuity.According to the International Society of Sports Nutrition, a safe dosage for indicated populations is approximately 3-6 mg/kg (it’s all based on body mass). However, as little as 100 mg can be effective at improving physical and mental performance when caffeine is consumed in anhydrous form (non-water source) such as a gel, pill or even gum.Responsible use of caffeine has been shown to extend exhaustive, high-intensity, intermittent exercise as well as improve mental focus and decision-making due to caffeine’s effects on boosting adrenaline and dopamine.Contrary to popular belief, responsible consumption of caffeinated products does not induce diuresis (increased production of urine) and the mechanisms of exercise have been shown to lessen the diuretic effects during physical activity.Bearing in mind, the key words throughout this paragraph are “responsible and moderate consumption.”
Caution: Caffeine Doesn’t Affect Everyone in the Same WayCaffeine’s mechanisms can result in a myriad of outcomes that can be contraindicated for many populations. For example, irresponsible doses of caffeine can elicit diuretic effects at rest and increased heart rate, thereby making caffeine a compound possibly unsafe for pregnant women and patients with a history of cardiovascular or kidney conditions. Moreover, caffeine can enhance the effects of some medications or blunt the effects of others.Just like other food constituents, over consuming anything can be detrimental to one’s health. As always, people on medications should always consult with their physician about possible interactions with other supplements, foods and drinks.
A Few More Facts about Caffeine ConsumptionFurther safety considerations surrounding caffeine use are threshold tolerance and withdrawal. Simply, the more you consume the more receptors your body will produce. Accordingly, it will take more caffeine to feel the effects. Consequently, quitting will be more difficult because the withdraw symptoms are often intolerable: headache, irritability, stomach discomfort and inability to concentrate just to name a few.If you, or someone you know, are trying to cut back on caffeine it’s recommended they slowly wean off their “vice” because quitting cold-turkey can be challenging.Lastly, caffeine as an ergogenic aid or as the “best part of waking up” should be consumed in moderation, just like anything else we put in our bodies. References
- Goldestein, E.R et al. (2010). International society of sports nutrition position stand: caffeine and performance. Journal of the International Society of Sports Nutrition, 7:5
- Hewlett, P., Smith, A. (2007). Effects of repeated doses of caffeine on performance and alertness: new data and secondary analyses. Hum Psychopharmacol, 22(6):339-50.
- Mayo Clinic. (2014). Caffeine content for coffee, tea, soda and more. Accessed Feb 7, 2014.
- Smit ,H.J., Rogers, P.J. (2000). Effects of low doses of caffeine on cognitive performance, mood and thirst in low and higher caffeine consumers. Psychopharmacology), 152(2):167-73.
- The World Anti-Doping Agency. The 2014 Prohibited List. WADA. Accessed Feb 7, 2014.