Caffeine is our favourite stimulant, either as coffee or pre-workout.

The reason it has become so popular is because it fights off tiredness. Its stimulant effects are low level enough to be safe and it provides energy and promotes wakefulness.

Perception of energy is a huge deal for things like mood—but it also drives the mental performance that so many of our jobs require. The ability to be switched on and able to perform is huge for productivity, which is a major part of modern life.

Caffeine is king for this because it blocks tiredness signalling in the brain. Receptors for tiredness take caffeine, instead of Adenosine molecules, blocking the experience of fatigue.

Those adenosine molecules are still there, your brain just doesn’t respond to them if they’re not able to bind to receptors.

Benefits of Caffeine

We wouldn’t love caffeine if it didn’t have some benefits. Let’s look at the major benefits and how we use it.


Boosting feelings of energy is the main benefit.

We live stressful lives and it’s useful to be able to control our energy levels. Morning coffee is a tradition for so many people because it helps kick off the rust of sleep and pick them up.

Energy levels for lower-regularity users are more profound, while those with an extensive history of caffeine intake will experience fewer benefits. It pays to reduce caffeine intake regularity where possible.

Improving Performance

Mental performance is better when caffeinated.

Aspects of how well your brain works, such as reaction time and ability to ignore distractions, are significantly better while caffeinated. These make it a great choice for rapidly evolving choices in stressful situations, as well as staying locked in with a task.

These are classics for both the working and academic worlds, where caffeine intake does seem to be highest.

Physical Performance

Caffeine also directly and indirectly improves physical performance.

In a direct sense, it adjusts the neurochemistry of muscle signalling. Things like power are more resilient to fatigue and remain higher through a workout when caffeinated.

Equally, the general mental resilience to fatigue shows up in physical performance. Things like time to exhaustion and ability to “grit through” are higher in caffeinated people, which can improve performance indirectly.

Metabolic Uptick

As all stimulants, caffeine is also a way of increasing metabolic output.

The metabolism of a coffee-drinker, for example, is estimated to average out 100 calories higher per day than their coffee-free counterpart. These are based on individual responses, but even when we control for differences, caffeine seems to improve metabolism.

This can be useful during a weight-loss diet, where caffeine may also alter signalling for appetite. When you tell your body that you’re not lacking energy, you will be less hungry in the short-term.

Of course, this shouldn’t be a crutch to the way your diet works and should only be combined with a balanced diet.

Potential Drawbacks of Caffeine

Despite the benefits, caffeine is not simply all-good. It can have some negative effects that are worth considering if you’re currently slamming down 10 coffees a day.

If you’re experiencing these, it’s time to look at your use and evaluate what needs to change.

Adjustments to Anxiety

Caffeine is not for everyone.

Stimulants in general, and caffeine in particular, can elevate resting anxiety levels while increasing heart rate.

These are problems even in the short-term, where irritability may result, but especially in chronic use. Low-level anxiety and chronic stress contribute to issues like depression and anxiety disorders.

Reducing this influence can be a positive change, and it’s clear that caffeine-induced anxiety can be dangerous for those sensitive to anxiety or unfamiliar with intake. Caffeine can exacerbate problems for these people and may not be appropriate.

Sleep Quality

Caffeine can easily disrupt the quality and quantity of sleep.

Late-day caffeine intake interrupts natural tiredness-signaling. You want to be tired when you go to bed so that you can get to sleep quickly, stay asleep, and get as much deep sleep as possible.

Caffeine can interrupt this process—especially with the indirect effects of anxiety.

Anxious sleep is less restful at a physical and mental level, which can contribute to a decline in normal energy levels. This can easily lead you to a cycle of caffeinating to compensate for poor sleep, and so on.

Proper daily doses of caffeine (under 450mg) and proper scheduling are key to reduce these risks.

Crashing Risks

Caffeine crashing is a common experience of profound tiredness and fatigue when caffeine’s effects wear off.

Caffeine has a 6-hour half-life and people will generally reach this crash during the latter part of the working day on a traditional 9-5. It’s an unpleasant experience—and more so during those with higher tolerance who receive relatively little benefit during the early hours of caffeine intake.

There is very little real consequence to a caffeine crash, but it can lower mood while increasing irritability and negative emotion.

Improper Use—Terms And Conditions Apply!

The important thing to note is that caffeine use patterns are the main factor in real dangers. For most people, caffeine is safe.

However, the real risks come with overuse, improper scheduling, or use among people for whom it’s not intended. These include anyone with a heart condition, caffeine hypersensitivity, or even a known intolerance to stimulants.

Blood pressure can increase with caffeine over-intake, while factors like heart rate increase and hormonal response can tilt towards stress-hormones like cortisol.

Side-effects are also relatively common—including jitters and headaches. These reflect unfamiliar doses or excessive intake but can occur easily in those without tolerance to caffeine.

Finally, digestive issues are relatively common. Caffeine-rich beverages, powders, and pills all carry the risk of cramping, while coffee especially comes with the risk of acid reflux.

In Summary…

Caffeine isn’t bad for you. Most use is associated with positive health effects and lifestyle changes, but this use pattern is what makes the difference between healthy and unhealthy.

Caffeine can be bad for you if it’s inappropriate for you personally—both in timing and dose. If you’re prone to side-effects or are stimulant-sensitive, then it can rapidly harm your health, while proper use tends to be a positive on balance.

“Is caffeine bad?” makes it a black and white, good or bad situation. That oversimplifies and what really matters is what your caffeine habits are like, especially compared to any pre-conditions that make it inappropriate for you.


  1. Natural caffeine in-matrix and health:
  2. Coffee, independently of caffeine, reduces diabetes risk:
  3. Caffeine can support healthy bodyweight:
  4. Combined benefits of Caffeine and L-theanine:
  5. Coffee reduces morbidity and inflammation in women:
  6. Rare cases of caffeine overdose:
  7. Caffeine worsens anxiety in susceptible patients:
  8. Caffeine may interrupt or crutch high-quality sleep:
  9. Caffeine may reduce sleep quality and quantity: