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Caffeine: Friend or Foe?

Post written by Eric Van Buskirk

For many people, coffee is a go-to when dealing with stress and anxiety. Everyone from university students to professionals in the business world use cups of coffee to deal with the pressures and tensions of everyday life, and for good reason. Caffeine, a pharmacologically active stimulant, is a major component in every cup of coffee. Studies have linked caffeine to increased alertness, improved energy levels and mood regulation. It can also improve athletic performance by increasing the availability of glycogen (a stored form of glucose) in muscles.

Composition of coffee

3-4% caffeine (75-100mg per cup)

4-5% tannic acid

12% simple proteins

12-15% fixed oils

Caffeine has been shown to enhance concentration, reduce fatigue and increase tolerance for lengthy work periods. However, it isn’t without its downsides for individuals with specific conditions and predispositions. In this post, we go over everything you need to know about coffee, caffeine, stress and anxiety — none of which can be properly understood without a crash course on human adenosine receptors.

What Are Adenosine Receptors?

To follow the interplay between adenosine receptors and caffeine, it’s important to understand how they work. Adenosine receptors (AR) are a network of protein-coupled receptors categorized into four groups; namely A1, A2A, A2B and A3. These AR groups can be found virtually everywhere in the human body, including in muscles, fascia and organs.

AR groups are established in scientific literature to play significant roles in a variety of physiological responses like inflammation, hunger, pain and vasodilation. Adenosine itself is a neuromodulator, which means it influences the way our central nervous system handles and/or responds to stress hormones like cortisol or inhibitory neurotransmitters like GABA.

The Good

Caffeine is a stimulant that affects the way adenosine receptors work in the body. More specifically, caffeine prevents adenosine receptors' function of slowing down your nervous system and brain activity. This is why caffeine consumption can help drinkers stay more alert throughout the day while also helping to improve focus and concentration. Caffeine also has a number of indirect benefits for relieving stress and anxiety, including:

Improving physical performance.

The vast majority of pre-workout supplements in the bodybuilding industry use caffeine as their primary ingredient. This is because it functions as a stimulant to increase focus and concentration while easing vasoconstriction, allowing much-needed blood and oxygen to get to your hardworking muscles.

Reducing risk of certain diseases.

Multiple studies, including one published by the American Diabetes Association, have linked moderate consumption of both caffeinated and decaffeinated coffee to decreased risk of type-2 diabetes. A growing number of studies also highlight the possible viability of caffeine consumption as a preemptive supplement against Parkinson’s disease.

Helping to prevent weight gain.

As any devotee of lunch break coffees will tell you, caffeine has a way of suppressing appetite while simultaneously staving off feelings of fatigue from lower-calorie diets.

Caffeine aside, a typical cup of coffee also contains a number of beneficial antioxidants and diterpenes. (Diterpenes assist with cancer prevention by blocking the activation of carcinogens and improving liver detoxification.)

The Bad

At the end of the day, caffeine is still a central nervous system (CNS) stimulant that can have both positive and negative effects on the human body. In moderation, caffeine can improve mental alertness and focus. However, too much can lead to a range of relatively minor yet undesirable effects, particularly in people with caffeine sensitivity. Let’s look at some of the most common health risks linked with this condition below:


Contrary to the popular generalization, caffeine can actually increase anxiety levels in caffeine-sensitive individuals. When caffeine is consumed, it travels to the brain where it binds to adenosine receptor groups, which blocks the calming effects of adenosine. This can increase levels of dopamine and norepinephrine—two of the chemicals most commonly associated with anxiety disorders.


Commonly described as “a feeling of general unease," restlessness can be accompanied by a sense of irritability, edginess, or nervousness from decreased adenosine activity in the brain. It’s worth noting that some people are more sensitive to the effects of caffeine than others and may experience restlessness even at lower doses.

Sleep disruption

Too much caffeine can keep you awake at night and make it difficult to get eight full hours of quality sleep. While it’s okay to have a cup of coffee or two in the morning and throughout the day, it’s best to avoid drinking caffeinated beverages later in the evening, particularly if you’re caffeine-sensitive.

The Bottom Line

If you are sensitive to caffeine, it’s best to avoid coffee or limit your intake. If you find that you regularly feel restless from caffeine, it may be time to cut back or quit altogether. In any case, there are many ways to reduce or eliminate anxiety and stress other than caffeine consumption; millions of people around the world, for instance, make regular use of techniques like exercising, seeing a therapist, or journalling.

Caffeine sensitivity aside, coffee can be a delicious and viable supplement to conventional therapies, techniques and medications for treating symptoms of stress, anxiety and mood disorders.

Want to learn more about how your diet can decrease symptoms of stress and anxiety? Contact us to book an appointment for nutritional counselling!


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