Caffeine Bomb: What Caffeine Does For You and To You

Caffeine is the world’s most commonly used performance enhancing drug. For many of us, a cup of coffee gets us out of our beds in the morning, and it’s well known as ‘wake-up juice.’ 

First, what is caffeine, and what does it do at the basic level? 

Caffeine is a stimulant drug that imitates the effects of epinephrine, or adrenaline, in the brain and body.  Technically it’s a bitter white alkaloid, which explains the appalling taste of caffeine diet and ‘stay-awake’ pills. In the brain, caffeine attaches to the same receptors as a chemical called Adenosine. Adenosine is a chemical that has several jobs in the brain, but one of them is to make you feel tired. As a result, when caffeine binds to these receptor sites it prevents you feeling tired and helps you feel energetic for longer.

Caffeine keeps you awake by both binding to adenosine sites and by increasing the rate at which your synapses fire.  But there’s more to caffeine than wakefulness.

Some people are dubious as to caffeine’s status as a performance enhancing substance, but Dr. Mark Tarnopolsky of McMasters University, Canada, isn’t one of them. 

‘There is so much data on this that it’s unbelievable,’ he told the New York Times in 2009. ‘It’s just unequivocal that caffeine improves performance. It’s been shown in well-respected labs in multiple places around the world.’

For some time, the main mechanism by which caffeine improved sports performance was thought to be its effects on fat burning. Caffeine tends to help muscles use fat as a fuel, meaning that more glycogen is available for longer, which would tend to improve performance in endurance events. This explanation dates back to the origins of research into caffeine as a sports supplement in the late 1970s. But this theory alone wouldn’t explain the effect, documented anecdotally and in tests, that shows caffeine enhancing performance at sports that aren’t endurance based at all. 

Read More: Positive And Negative Health Effects Of Caffeine

How can fat burning make you a better sprinter? Could it be the placebo effect?

Perhaps, but Dr. Tarnopolsky’s research indicates that caffeine increases power by triggering the release of calcium stored in muscle tissue.  This effect can enable improvements in both endurance and in strength and power during sports, and Dr. Tarnopolsky’s team saw improvements in the 20 to 25 percent range in laboratory conditions.  The real world improvements are thought likely to be less than this impressive statistic, probably more in the 5 percent region, though this would still be a significant bump for athletes working to shave a few seconds off their times or squeeze a few more pounds on the bar. 

How Much Caffeine Do You Need - And Are There Any Drawbacks?

There’s also some research to indicate that caffeine’s fame as a performance enhancing drug sets us up for a fairly strong placebo effect too. Research by Derby University’s Sports Science department indicates that the placebo effects may be equal to the actual effects, which for an athlete means a ‘double bump’ – placebo effects are real, after all!

The other issue is how much caffeine you need to use to get the sports enhancing effects.  Scientists have thought for some time that intakes of about 5 to 6 milligrams per kilogram of body weight (about 3mg/lb) was necessary for athletes to get the full effect of caffeine and unlock their true potential.

However, Louise M. Burke, the head of the sports nutrition department of the Australian Institute of Sport in Canberra, has a different take. She found that athletes get the full suite of caffeine effects with as small an intake as 1mg per kilogram of their body weight, meaning that an average-sized, 80kg (176lb) male athlete would have to drink only 4 ounces of coffee to get the full effects – rather than the 20 ounces he was encouraged to drink previously!

There are other benefits to caffeine than the sports effects.  Caffeine improves reaction times – a major plus for drivers, where a split second can literally save lives – and it also increases the rate at which short term memories are converted into long term ones in the brain, resulting in improved learning abilities that are especially helpful for college students. Caffeine improves cognitive function too, meaning you can think better and more effectively when you have a cup of coffee. Finally, caffeine acts on the parts of the brain that detect carbon dioxide in the blood, making them more sensitive.  As a result, caffeine tends to increase blood oxygen as users breathe more deeply.  The jury’s back: Whether you have a race or an exam, a cup of Joe is just the thing, evidently.

Read More: Ten Surprising Caffeine Myths And Facts

So what are the drawbacks? 

No pro comes without a con, and caffeine is no exception.

Caffeine is a diuretic, meaning it causes water to be taken out of the blood by the kidneys and transferred to the bladder where it must be passed as urine.  The contribution to dehydration that this effect makes has been vastly overstated, though; modern medical opinion is that habitual coffee drinkers become acclimatised to this effect very quickly – within a few days – and the coffee they drink does not dehydrate them. Intense coffee drinkers may, however, need to go to the restroom more often. The other common side effect, increased heart rate and blood pressure, is also one that habitual users become immune to very quickly. 

The major downsides to caffeine use are that it tends to keep you awake, and there are short term side effects of overconsumption including headaches, nausea and anxiety.  The short term side effects usually wear off in a few hours, but the half life of caffeine in the body – the time it takes to get rid of half the amount of caffeine in your cells – is about four hours.  If you drink a cup of coffee at lunchtime your system will still be running on caffeine fumes at 3AM, meaning that you’ll struggle to sleep if you used caffeine as a workout supplement or to study more effectively. It’s in anxiety and lack of sleep that the downsides of caffeine use show themselves: otherwise it’s pretty harmless and almost entirely beneficial; and while you can become acclimated to its negative effects, you never become immune to its performance enhancing properties, according to Dr. Tarnopolsky.