Day 29: Caffeine

                I love coffee. One of the first things I do when I wake up is grind up some coffee beans & start the coffee maker. On average, I drink 4-5 cups of coffee per day, which is A LOT. I drink my coffee black so it was never a caloric concern, however in the back of my mind I have always wondered if there were any negative health impacts on the amount of caffeine that I consume. 

                The main reason I wanted to research the topic of caffeine was because I am currently attempting to increase the amount of sleep that I am getting per night, & likely in direct opposition to that goal, is my caffeine consumption. When I started my research, I expected to find a lot of information regarding consuming caffeine before bed. What I did not expect to find was all of the research suggesting that caffeine can actually increase athletic performance.

Caffeine: the performance-enhancing drug?

Caffeine is found in most pre-workout supplements, usually in quite high doses. Further, until 2003 the International Olympic Committee considered high caffeine levels a doping violation. Although it makes intuitive sense that more energy would equate to better athletic performance, has it ever been proven? It turns out that it has, & that the positive effects of caffeine prior to exercise have been replicated in many different studies over the past 20 years, although the mechanism behind why caffeine increases athletic performance is still up for debate.

What has been shown is that caffeine has effects directly on muscle contraction & in the release of adrenaline in the body which can lead to increased athletic performance in activities requiring short bursts of strength & energy, commonly referred to as ‘intermittent athletics.’

Perhaps the more intriguing concept that is more difficult to prove it that caffeine provides a large part of its benefit by altering the central nervous system’s perception of effort & fatigue. In effect, caffeine tricks our brains into feeling less fatigue, so we can perform more effectively. 

                In a study where athletes were instructed to consume caffeine prior to running a 1500m race, finishing with a 100m burst at maximum effort, it was shown that the athletes who were given caffeine decreased the time taken to run 1500m, increased the speed of the ‘finishing burst’ & increase VO2 during the high-intensity1500-m run. Although the various effects were marginal (0.1% - 2.5% increase), in high-level athletics these differences can make the difference between a podium, or a 4^th place finish.

Caffeine & Dehydration 

                A common concern for endurance athletes is that caffeine causes dehydration which can lead to cramped muscles & decreased performance, however recent studies suggest that typical doses of caffeine have a very minor effect on hydration, & no impact on a fluid-electrolyteimbalance that is detrimental to exercise performance or health. Further, tolerance to caffeine reduces the likelihood of hydration even further, so although race day is likely not the best time for you to begin experimenting with caffeine, if you are a coffee-drinker or have consumed caffeine in some other form with even semi-regularity, you need not worry about dehydration provided you stay within the 200mg – 400mg range (2-3 cups of coffee).

Caffeine’s impact on sleep 

                Another indirect way that caffeine can effect athletic performance is the drug’s effect on sleep. It seems obvious that caffeine would have a negative impact on sleep, however the question is how long before bed should you stop consuming caffeine? 

                A recent study showed that caffeine consumption can still have a significant, negative impact on sleep quality when consumed within 6 hours of rest. The study tested the sleep quality of subjects who were given caffeine 0, 3, & 6 hours prior to bedtime. The subjects were asked how they slept, & also had key sleeping metrics measured throughout the night. 

                What the study found was that a moderate does of caffeine at bedtime, 3 hours prior to bedtime, or 6 hours prior to bedtime each have significant effects on sleep disturbancerelative to placebo. 

                While subjects that consumed caffeine 0 & 3 hours prior to bed reported significant sleep disturbances, the subjects that were given caffeine 6 hours prior to bedtime were shown to lose more than 1 hour of sleep per night due to caffeine-related sleep disturbances, even though they did not report the decreased quality of sleep. 

                With 90% of people consuming caffeine in the afternoon (12PM-6PM) & 68.5% at night (6PM-12AM), it is no wonder that many of us are so tired during the day. Clearly this shows that coffee or energy drinks should not be consumed at night, however perhaps the bigger takeaway for fitness enthusiasts that workout in the evenings is that it may be time to put that pre-workout aside. 

Caffeine health risks

In attempting to find information on the health risks & addictive properties of caffeine, I found a lot of conflicting research. While it is clear that high doses of caffeine can cause heart palpitations, anxiety, & gastrointestinal upset, there are not a lot of studies linked to the harms of long-term caffeine exposure.

My major takeaway from the studies that I did review was to keep caffeine consumption to reasonable levels; an Australian study that reviewed 911 calls related to energy drinks from 2003 to 2010 found that the average person that called had consumed on average 5 energy drinks, often mixed with alcohol or other drugs.

It appears that the major health risk posed with moderate caffeine consumption is a lack of sleep, however caffeine should not be consumed by children or those with pre-existing heart conditions, should not be mixed with alcohol or any other drug, & should be consumed at moderate levels.

In conclusion it appears that, yes, caffeine does have a negative impact when consumed within 6 hours of sleep. Perhaps most interestingly, despite costing you an hour of sleep, the effects of this loss of sleep appear to be unnoticed by those incurring the sleep loss. Additionally, it appears that caffeine does have a positive, albeit small, effect on athletic performance. For me personally, since I usually workout at night, I will not be adding caffeine to my pre-workout routine as I do not want to incur the loss in sleep quality associated with caffeine, however I will certainly be consuming caffeine prior to my weekend morning workouts, as well as on race day.

100 Day Spartan