Caffeine Tolerance?

Every Tuesday and Thursday I get my energy booster, coffee, to push me through the long day. Today, my energy buzz did not seem to last as long and I started to wonder whether I am beginning to develop a tolerance for caffeine, or if that is even possible. I notice many other college students consuming the caffeine filled beverage, some using it as a crutch. I already know caffeine is addictive, but I am curious as to how the ingredient interacts with the body or the brain to give the reaction it does. Also, I wonder if there can be a tolerance built up for it.



Neal J. Smatresk explains how caffeine temporarily interferes with natural body chemicals. He says it blocks a neurotransmitter called phosphodiesterase, (PDE for short) which has a very important job. PDE helps get rid of cyclic adenosine monophosphate (also known as cAMP), so caffeine eventually leads to the inhibition of cAMP being disposed in a timely manner. With cAMP lingering, a chain of reactions occur that result in the common hyperactivity experienced during a caffeine buzz. The heart speeds up and goes faster, which also causes there to be more oxygen to be delivered to the brain, and also a higher than normal blood pressure. The chemical processes are not the only effects seen from caffeine.

As I said early, a lot of college students are familiar with the physical experience caffeine gives. I get extra caffeine on Tuesdays and Thursdays to keep me awake and my experience is backed up by data. In a random double blind experiment conducted by Wing Hong Loke, students at the University of Iowa were randomly split into three groups.  Each participant had a capsule given to them with either a placebo with no caffeine, 200 mg of caffeine, or 400 mg of caffeine. Just like when I drink my coffee, the group that had 400 mg of caffeine were less tired. The Alcohol and Drug Foundation list some other common short term effects such as anxiety, alertness, frequent trips to the bathroom, and stomach pain. Especially with finals coming up, I expect more and more students to be taking advantage of these effects to spend long nights studying.

Some people claim to need caffeine to function regularly which is a sign of the tolerance that can be developed from habitual caffeine use. In one study at Vanderbilt Medical Center done on adults of varying ages from 21 to 52, caffeine and a placebo were varied in their meals for 21 days. A tolerance was observed to be developed after 3 days. The blood pressure spike that we’ve learned happens from caffeine did not happen in subjects on the 3rd straight day of caffeine. These results show that tolerance of caffeine can be developed, and my original hypothesis is correct.

I wonder if because I do not have coffee for consecutive days, if my tolerance has taken longer to develop. I know I consume caffeine in a lot of other aspects of my diet, but maybe not as much as the days when I have a coffee. Confounding variables could also be playing a role in my tolerance and the group in the study is slightly different from me. They were on a controlled and monitored diet, and had not had any caffeine in the 3 weeks before the study took place.

I was able to answer my question of how caffeine works internally, and also confirm my hypothesis of a tolerance being developed.

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