How does coffee wake you up?

In this brief guide, we are going to answer the question “how does coffee wake you up” with an in-depth analysis of chemistry lying behind the action of coffee on the sleep and awake cycle. Moreover, we are going to discuss the effect of caffeine on the body and the way to properly store coffee.

So without much ado, let’s dive in and figure out more about it.

How does coffee wake you up?

Caffeine is the stimulant present in coffee that keeps you awake. So, when you drink a cup of coffee, the caffeine enters your bloodstream and travels to your brain, where it attaches to the adenosine receptors. 

Now that caffeine has connected to the adenosine receptors, the adenosine will be unable to adhere to the receptors and hence will not be able to perform its function.

The stimulating effect of coffee is well known and is due to caffeine’s ability to enhance mental performance, which includes enhancing alertness and perception. 

Generally, a dose of 75 mg is required to obtain these effects, although very large differences in individual responses to caffeine are observed.Caffeine consumption can also improve other functions such as memory and mood.

Coffee components other than caffeine have also been shown to influence cognitive performance, though to a smaller extent than caffeine.


Adenosine is a neurotransmitter that controls the sleep cycle as well as alertness and attentiveness. As soon as adenosine binds to its receptor, it sends a signal to the brain that it’s time to sleep. It works by sending impulses to your brain to make you sleepy.

Now in the scenario, where caffeine has blocked all the adenosine receptors, so when adenosine won’t be able to bind with its receptor, it won’t be able to carry out its function, thereby you will stay awake. (1)

What is the caffeine content of coffee?

The caffeine content of coffee varies according to the species; it can range from 50 mg/100mL (a normal weak coffee beverage) to 380 mg/100mL (a very concentrated extract)

Environmental and agricultural factors appear to have a minimal effect on caffeine content. During roasting, there is no significant loss in terms of caffeine, its concentration will increase due to the degradation of other components.

A typical cup of regular coffee beverage contains 70–140 mg of caffeine, depending on the preparation, blend, and cup size. (2)

What are the effects of caffeine on the body?

Caffeine causes an increase in heart rate, breathing rate, and mental alertness through increasing cortisol and adrenaline secretion in the body. 

It also stimulates your neural system, which helps you focus and stay alert. Additionally, coffee includes dopamine, a brain booster that helps you stay focused and alert.

Caffeine enters the bloodstream quickly after being taken because it may easily pass through the epithelial layer lining the mouth, throat, and stomach. Caffeine takes 30-60 minutes to reach its highest concentration and offers you a burst of energy.

Caffeine has a half-life of about 5 hours in an average adult body according to the stats provided by the American Academy of Sleep Medicine. This means that half of the caffeine, as well as half of its effect, is gone within the first 5 hours.

Additionally, coffee has been shown to help prevent degenerative disorders, many of which are related to neurostimulating,antioxidant and anti-inflammatory effects. 

The consumption of coffee has been linked to a notable decrease in the risk of death related to heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections. (1, 3)

What happens if you consume too much coffee?

Excessive coffee intake can give rise to a range of adverse effects on the body. While caffeine initially delivers a stimulating boost, it can subsequently lead to crashes, leaving certain individuals experiencing sudden fatigue and sleepiness.

Moreover, coffee has the potential to trigger anxiety due to caffeine’s capacity to obstruct adenosine, a chemical that plays a role in preventing fatigue.

Consuming excessive amounts of caffeine can lead to fatigue, nausea, and may even contribute to the development of caffeine-induced anxiety disorder.

In fact, an intake of approximately 1000 mg of caffeine per day can result in symptoms such as nervousness, jitteriness, and nausea. (1,3)

Consuming excessive amounts of caffeine can have notable consequences for both the body and the brain, particularly impacting the gastrointestinal (GI) system. 

An overstimulated nervous system can adversely affect the colon and GI tract, leading to discomfort in the stomach.Furthermore, due to its acidic nature, coffee can exert a considerable toll on the stomach. 

Acidic beverages, including coffee, have the potential to trigger digestive problems like ulcers and heartburn. For some individuals, consuming large quantities of caffeine can result in painful gastrointestinal symptoms. 

In cases of caffeine toxicity, adverse effects such as diarrhea, nausea, acid reflux, and gas may manifest.(1)

Consuming a higher amount of coffee can potentially lead to insomnia as it acts as a sleep deterrent and can disrupt the natural sleep cycle, especially when consumed later in the day.

The impact of caffeine on sleep can differ from person to person. Excessive intake of caffeine can significantly delay the onset of sleep, regardless of the timing of consumption. 

On average, it takes around five hours for the effects of coffee to wear off. However, it’s important to acknowledge that the duration can vary significantly, ranging from as short as half an hour to as long as nine hours, depending on individual factors. (1, 3)

Is it possible to develop a tolerance to coffee?

Yes. As with any drug, regular caffeine users will establish a partial tolerance to caffeine.However, studies have shown that this tolerance only applies to effects such as jitteriness,anxiety and an increased heart rate. 

Users do not develop a tolerance to the benefits of caffeine consumption such as improved mental performance, although sometimes slightly higher doses of caffeine are required.  (1)

Other FAQs about Coffee that you may be interested in.

How does Starbucks decaffeinate its coffee?

What to do if I accidentally bought whole coffee beans?

What happens when adding coffee to chocolate cake?


In this brief guide, we answered the question “how does coffee wake you up” with an in-depth analysis of chemistry lying behind the action of coffee on the sleep and awake cycle. Moreover, we discussed the effect of caffeine on the body and the way to properly store the coffee.


  1. Farah, Adriana.  Nutritional and health effects of coffee. 10.19103/AS.2017.0022.14. 2018.
  2. Wei, F., & Tanokura, M. Organic Compounds in Green Coffee Beans. Coffee in Health and Disease Prevention, 149–162. 2015.
  3. Willson, C.  The clinical toxicology of caffeine: A review and case study. Toxicology Reports. 2018.

Was this helpful?

Thanks for your feedback!