Short- and Long-term Effects of Caffeine on the Human Body

Caffeine has short- and long-term effects on the human body, and even a cup of coffee can do you either good or bad. What can caffeine do to us within a few hours or days? Let’s find out.

As we’ve mentioned before, caffeine is an indirect stimulant to the nervous system. However, it affects not only cerebrum but other key internal organs as well, so it’s good to be aware of basic effects not to do more harm than good. On the other hand, why not bring about a more controversial issue of how one can benefit from caffeine? Let’s see what we’ve got. 

Fancy that! Statistics show that about 82% of the people (including you) consume caffeine daily. In fact, caffeine isn’t contained solely in coffee; green tea has high concentration of it, not to mention medicaments. We’d recommend being mindful of the composition of liquids and drugs every time you are to take any.

How long do the effects of caffeine last?

It takes about 15 hours for caffeine to be metabolized in your system, which is relatively fast. We are now going to look into short-term and long-term effects of coffee on the human body, which differ in time.

Short-term (immediate) effects of caffeine

The peak caffeine effect is observed within the first 30-60 minutes, and it’s an immediate effect of caffeine. To put it simple, if you have a cup of coffee, tea or another caffeinated drink in a café, for example, you’ll feel the effect immediately.

In other words, short-term effects of caffeine are evident both to advanced level coffee drinkers and beginners, while possible influences on the body have been thoroughly examined by researchers. Here are some of them which are considered unquestionable:

●   Increase in blood pressure. According to medical researches, an increase in blood pressure is the most vivid short-term effect of caffeine. Temporary pressure swings are especially noticeable for those who drink coffee seldom, because their body isn’t used to regular caffeine stimulation. For regular coffee drinkers caffeine’s effect on blood pressure gradually gets smoother, and the dose of caffeine to cause an increase in blood pressure grows.

●   Temporary energy flush, awakening effect. The brain acquires better focus and becomes resistant to distractions. This is how caffeine improves brain activity and focus on work, both physical and intellectual.

●   Diuretic action. A number of medical researches show that caffeine is a relatively weak diuretic. However, small cup of coffee catalyzes perspiration and uropoiesis processes. If you have a coffee before doing sports, you are most likely to notice this post-caffeine effect, as you sweat more heavily in comparison with the same amount of exercise but without a coffee dope. That’s why sportsmen tend to drink no coffee before a workout not to feel discomfort caused by a diuretic effect of caffeine.

●   Improves motility and reaction. It’s been proven by researches that sportsmen who have one or two coffees (circa 100mg) before a workout feel more energetic and have better reaction, though in general using such a dope can have a negative effect on the body. To avoid this and reach positive effects, keep track of how much caffeine you use, a reasonable dose defined by a therapist.

Suggestion. If you do sports (go to the gym, do cardio exercises, etc.), go easy on caffeine before workouts, which especially concerns  hypertension sufferers. Imagine that even one little espresso can get you down!

●   Mood booster. The effect of caffeine on the central nervous system is such that it prevents dopamine and serotonin from getting to the brain for a while, which allows to improve your mood almost effortlessly or helps to take no notice of what worries you. Still, negative effects, such as anxiety caused by uncontrolled coffee drinking coupled with depressive mood susceptibility, mustn’t be ignored. We’ll dwell on them in the next articles.

Long-term Effects of Coffee

As caffeine is metabolized in the body system very quickly, its short-term effects are numerous and last till at least half of it is removed from the body. Nevertheless, there are also long-term effects of caffeine and they last longer.

●   Caffeine dependence. As any other drug, caffeine can cause dependency, but the severity of it is individual. A person with caffeine dependency has to increase the quantity of coffee, often unaware of it, to reach a desirable effect, so one or two cups turn into four and more. We are going to talk about the subject of caffeine dependency later, in the next articles, now simply mentioning that it’s up to the “drowner” to decide on the “submersion” depth.

●   Sleep deficit, insomnia. We’ve already described some positive effects of caffeine on focus and productivity in the daytime. As for drinking coffee at night, in some cases, like night driving or working, it is essential. Meanwhile, it becomes a habit carrying sleep disorders.

●   Irregular heartbeat. Last but not least, caffeine can be a culprit of irregular heartbeat (see Increase in blood pressure). You should be aware of this, especially when you are a passionate coffee drinker and a sportsman (cardio sorts in particular). In the long-term, caffeine will raise the bar till the moment its negative effects are overwhelming.


If you were reading attentively, you might have come to some super important conclusions. For example, that short-term effects of caffeine (energy flush, focus, mood improvement) definitely make it appealing, while long-term effects (when coffee is consumed uncontrollably) can cause undesirable consequences.

What else should I say: drink coffee, but don’t overdo. Treat your body with care, consult specialists about the quantities and be attentive to minor changes in the ways coffee affects you. Keep healthy!