Thursday, July 15, 2010

Substance review: Caffeine

So I've just sat down and sucked back an energy drink laden with caffeine and I'm getting some familiar feelings. After a few minutes of staring at a mountain of emails, I start becoming more alert and I'm now ploughing through them. The sluggish feeling is shrugged and my fingers rain forth words in a flurry of activity.

Caffeine has been consumed in some form or another for almost as long as we've been able to record history, probably at first through the drinking of teas. Its pharmacological effects became better studied with the rise in the popularity of coffee during the 15th century. Caffeine was isolated as the active ingredient in products like tea and coffee by Friedlieb Runge in the early 19th century, but it took the modern application of the food and beverages industries' marketing to really kick off consumption.

The caffeinated soda drink Coca Cola was launched in the late 19th century before rocketing to its status as an American icon and the undisputed champion of the soft drink market. Red Bull then upped the stakes in the late 20th century when it successfully promoted a westernised version of an Asian energy syrup, more than tripling the caffeine content (per 100ml) of Coca Cola. Fast forward to today and we have a $5.7 billion industry for energy drinks along with the more traditional outlets like tea, coffee and soft drink.

I can only assume caffeine is such a popular stimulant because not only is it legal in just about every country in the world, but it also has some pretty obvious effects. I'm feeling a boost in productivity right now, people also note they feel more alert and their mood is elevated. These all sound like positive attributes for a mental enhancer, but most of the caffeine in the highly caffeinated drinks comes from decaffeinated coffee. If people are decaffeinating their drinks then it follows that people out there feel there are some significant negative effects of caffeine.

Caffeine works because it closely mimics the neurotransmitter adenosene and competes with it when attaching to receptors. Whereas adenosene's job is slow the nerve cell activity down before periods of rest, Caffeine attaches to the same receptors but does not effectively activate the receptors that slow down cell activity.

The pituitary gland is a part of the brain that regulates many bodily function including metabolism. It recognises the increased levels of cell activity caused by the caffeine blocking adenosene's effect so it triggers the release of epenephrine.

Epenphrine is commonly known as adrenaline, the hormone that puts the body in a state of preparedness for danger. This includes phenomena like reducing blood flow to the skin to stop bleeding, increasing blood flow to the muscles to improve activity and the liver releasing sugar for a quick energy burst. It also constricts blood vessels in the brain which can aid in some types of headaches.

Caffeine constricting blood vessels in the brain sends warning signals over its usefulness as mental stimulant. Other problems with caffeine include the side-effects of withdrawal from constant use. After constant consumption of caffeine sensitivity to adenosene would have increased to compensate for the caffeine inhibiting its effects. This in turn leads to increased sleepiness, lack of motivation and concentration - all of great concern to cognitive performance.

What then is the trade off in caffeine's use? How do we decide whether the benefit of caffeine's epenephrine release is worth the cost?

In the next post I will discuss the implications of some its effects onto an athlete who wants performance bothphysically and mentally.

Sources and further reading:

Photo by Carlos Porto

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