Caffeine Benefits and Risks

Caffeine Benefits and Risks

Caffeine is consumed everyday by millions if not billions of people worldwide. However, it is mostly consumed to stimulate feelings of focus and reduce tiredness

We look at the other benefits.

LAST UPDATED: March 2019 by Ben.

This review of caffeine features cited references of studies from reputable sources.

Caffeine Improves Physical, Cognitive Performance & Burns Fat

Caffeine is the worlds most used drug.

And, it has many supposed benefits. Including not only physical but also mental performance.

We look in to how the mechanisms work and the proof behind the claimed benefits.

Central Perk

caffeine in coffee

There is no doubting the popularity of caffeine. It is in your morning coffee to get you out of bed and in your afternoon cup of tea.

The plant for which coffee is derived, Coffea Arabica, stems from Ethiopia with Yemen being documented as the first country to cultivate the plant.

Since its humble beginnings from Arabia it is now the worlds second most popular beverage, water being number one.

Around 1.6 billion cups of coffee are drank daily.

Most people ‘use’ caffeine globally with the majority of people motivated by roughly two effects:

  1. Energy
  2. Concentration/focus

This why coffee is so popular (I’m drinking a cup now), in fact caffeine has found its way in to more than just an espresso.

Caffeine is now in energy drinks, dessert like iced coffee’s, chocolate, soft drinks, nootropic supplements and even fat burner supplements.

Caffeine is such a hot topic that even the U.S Army has released a study to illustrate what the best dosing strategy is for maximum benefit. [14]

So, just how effective is caffeine to help increase energy and focus?


Physical Performance

Caffeine has been under scrutiny since the 1970’s to see what its effects are on exercise and sports.

As a result there are plenty of studies telling us of the benefits of caffeine, in fact here is a quite from a published article by a research team from one of the UK’s leading universities in sports research.

‘Caffeine in a performance bar can significantly improve endurance performance and complex cognitive ability during and after exercise.’ [1]

We could almost leave it there and be done with it. Caffeine helps improve physical and mental performance. The end.

However, let’s look further in to the reasoning behind how caffeine works and why it does have a positive effect on us.

And why it is foolish to omit it from your supplement stack.


The stimulant effects have been known for hundreds of years, and in the 19th century a famous French novelist became dependent on its benefits.

Caffeine appears to act as a central nervous stimulant. However, because caffeine interacts with many different tissues it’s difficult to study its effects on the central nervous system.

We know that once ingested, its effects make their mark after about 30 minutes.

The caffeine is distributed across the body after being metabolised by the liver and can last for up to 12 hours.


Caffeine works on the body by blocking adenosine receptors.

This is important because adenosine is one of the sleep regulating molecules that is located in the central nervous system.

Furthermore, adenosine can lock itself with different receptors in your brain.

When Adenosine locks with the A1 receptor it relaxes the muscles and makes you feel tired.

However, when caffeine is ingested it can block this action and makes you feel more awake.

Additionally caffeine also gets in the way of Adenosine locking with the A2A receptor.

The A2A receptor can promote the release of dopamine, moradrenalin and glutamate.

This action makes you feel better.

Catecholamine Signals

Because of the aforementioned actions of increasing of catecholamine signalling (adrenaline and dopamine) caffeine not only makes us feel good but improve focus for cognitive function.

caffeine syringe


So that is how caffeine works on your body, in a very simplified and concise summary.

But how do we benefit from caffeine?

There’s five areas of note, some of which we have already mentioned:

  1. Improved physical performance
  2. Cognitive enhancement
  3. Fat burning
  4. Increases recovery
  5. Military

Exercise Performance

There are numerous studies available to conclude and confirm that caffeine has a heavy effect on exercise and physical performance.

Read on to see why you should consider using caffeine to improve your performance.

As study involving cyclists to measure their power output concluded that after dosing 5mg per kilogram of body weight their average power output was increased significantly. [3]

To mix it up a bit l will include research regarding resistance training. Weight lifting to you and me.

The aim was to establish how caffeine could affect strength performance and muscle pain of 11 individuals who were familiar with weight training.

This study concluded that the participants hit higher reps to failure on numerous compound exercises after ingesting caffeine than without.

In addition, when the participants had consumed caffeine their pain perception was significantly lower than when they used a placebo. [4]

Another study examined the performance of male and female volleyball players.

The results showed that those who took caffeine demonstrated that physical performance (including agility and jump tests) and accuracy was better than the placebo group. [10]

Cognitive Function

It seems that caffeine can be of benefit to restore memory impairment as well as preventing and lowering the risk of further developing Alzheimer’s disease. [5]

Caffeine has also been found to help prevent motor symptoms and Parkinson’s.

Further studies also conclude that caffeine can improve brain function in order to complete complex attention task as well as increasing alertness and caffeine also benefits executive control function. [6]

These latest studies demonstrate that caffeine has clear cognitive benefits, these effects are greater than previously thought.

The cognitive benefits are confirmed by reports from a military study which states a 150mg dose of caffeine enhances cognitive performance for at least 10 hours after ingestion. [2]

Is Caffeine Good For Losing Weight?

Yes, it is true. That trusty caffeine can help burn fat and lose weight.

Part of this is down to its ability to raise the body temperature and increase the metabolic rate. [7]

Caffeine actually increases fatty acid oxidization. [8]

In essence, this means that your body depends less on glycogen (glucose stores) for energy.

Caffeine increases lipolysis which uses stored fats for energy when you are exercising or in a state of fasting. [9]

In another study, evidence demonstrated that a combination of aerobic exercise and caffeine significantly reduced fat cell size compared to when caffeine was not ingested prior to training sessions. [10]

Caffeine to Reduce Muscle Soreness

It seems to be common knowledge that caffeine can improve physical performance, and we have used different studies to reassert that theory in this article.

However, using caffeine in order to reduce muscle soreness, in particular delayed onset muscle soreness (DOMS).

I read through a number of studies that have taken place to understand exactly if caffeine can have a positive effect not just during performance but afterwards, too.

One particular research paper struck a chord with me which involved 9 men performing bicep curls on a preacher bench.

The results showed that caffeine ingestion significantly reduced levels of muscle soreness up to three days after exercise. [11]

It also increased the number of repetitions of bicep curls performed.

This benefits trainees threefold:

  1. Increase repetitions
  2. Reduce soreness
  3. Reduce number of days recovery, therefore increase training frequency

Military Use

british military ration pack containing tea and coffee

What has the military have to do with caffeine?

The British Army have always found an opportunity drink a cup of tea, regardless of the situation or battle going on around them.

The tanks and troop transporters even feature a kettle for a ‘brew up’ to sustain the troops.

In fact, during my training, emphasis is placed on ensuring that while you are living in the field, the initial part of your morning routine is to get hot water boiling for your breakfast and a drink of tea or coffee.

Anyone who rejects that idea is strongly persuaded otherwise…

But, not only is this to warm your body up and improve morale, it serves a very important function.

During initial training, there’s periods of days whereby sleep is extremely limited and you are out on patrol under simulated exercises.

A study discovered that caffeine has a positive effect on marksmanship during military training whereby the soldiers are under a high level of stress coupled with low amounts of sleep.

Caffeine supplementation meant that soldiers were able to aim and pull the trigger quicker than those who had no caffeine administered. [12]

Side Effects

Caffeine can hold you liable to two forms of risk:

  1. Legal (sort of)
  2. Health


Okay, taking caffeine is not illegal. We would all be in jail if so and Starbucks would be El Chapo.

However, if you play sports competitively you need to know the rules.

Caffeine when its concentration is greater than 10mcg per ml of urine is prohibited according to the World Anti-Doping Agency. [13]

This equates to around 5-6 cups of coffee.


While caffeine tolerance dosing is still unclear, it is understood that a dose of 250mg is about optimal.

Doses over 600mg per day can lead to caffeine toxicity.

This can result in anxiety, tremors and result in your heart beating at over 100bpm at rest.

Acute toxicity which can result in death is considered to be around 10g or caffeine per day. [14]

The majority of caffeine related deaths have been a result of mixing high doses of caffeine with drugs and/or alcohol.

In one case this has included alcohol and nicotine. [15]

It is also worth noting that caffeine is a diuretic. This means it helps you pass more urine.

If you are in a hot climate or doing high intensity exercise always remember to re-hydrate.

To Recap…Effects

The numerous studies from as early as the 1970’s have established that caffeine has multiple benefits.

Both physical and mental.

It is widely understood that caffeine is able to improve alertness while suffering from sleep loss and deprivation. [16]

Caffeine is able to improve physical exercise performance. It has been noted that it can improve the physical performance of athletes in multiple sports.

Caffeine has also been proven to improve alertness plus motor control. Including accuracy, executive function and attention.

It should also be mentioned that there appear to be positive benefits to help reduce and prevent the symptoms of both Alzheimer’s and Parkinson’s disease.

Furthermore it can improve fat burning by storing glycogen and the utilization fat for energy.

The additional benefits of caffeine also extend to reducing muscle soreness while being able to help increase muscular performance.

Optimal dose

All of these benefits comes with minimal risk. It seems there is no requirement to exceed a dose of 250mg which falls well beneath the amount that would trigger caffeine toxicity.

Any deaths appear to be the result of a combination of alcohol and other drugs.

In sort caffeine can help you perform to a higher levels on various platforms, no more is this apparent than what has been recorded in clinical trials with U.S Navy SEALS.

Their reports state that an optimal dose of 200mg of caffeine can provide an advantage when the person is under severe stress and require enhanced cognitive function. [17]

soldiers improved performance with caffeine


You may be surprised by which food sources contain caffeine.

Even the products which as ‘de-caffeinated’ contain caffeine, just at a lower level.

There’s the obvious choices such as coffee, or now the high influx of energy drinks but foods also contain caffeine.

Let’s take a look.


So, while not quite as obvious, some foods contain caffeine:

> Protein bars can contain caffeine and so can energy bars.

> Chocolate is a source of protein, so anything that contains chocolate such as cereal, ice cream, puddings and even cookies can be giving you a caffeine hit.

> Even some chewing gum contains caffeine.


This is where most people associate caffeine. That morning brew.

Yet, your coffee is probably going to offer the lowest hit of your day.

Some beverages offer over 300mg compared to around 80mg for a cup of coffee.

Whereas a cup of ‘relaxing’ tea can contain as much caffeine as a shot of espresso.

So, let’s look at the biggest caffeinated drinks culprits:

> Energy drinks such as NOS Energy. Green Tea, breakfast tea and coffee, including iced coffee’s.

> Soft drinks and soda such as cola and also ‘energy’ juices including smoothies and even bottled water.

The problem with many of these drinks and foods is that it is quite difficult to establish the level of caffeine which is included, or to even realise they include caffeine at all.

Then there’s some medicines such as headache or cold relief that also contain caffeine.


Many supplements include caffeine due to the high benefits and low risk.

So, if you do not fancy 4 espresso’s in a row but want a high dose for maximum benefit try a supplement.

These can be in water soluble powder form or capsule. Each one has it’s own benefit.

If you want a large, sudden hit before a training session you can find that a pre workout supplement can be beneficial.

A supplement such as 4GAUGE will offer a very quick hit of 150mg per serving helping you get through your gym session while increasing performance and aiding recovery.

With the benefits for weight loss, there are many dietary supplements available that include caffeine such as fat burners that offer a more gradual release through the use of capsules or pills.


So, what have we learned?

Well, it is the worlds most popular stimulant. With over a billion praying to the font of caffeine daily.

However, it has many benefits with few risks.

Even the military include caffeine as part of their nutrition packs, and it has been proven to enhance soldier capabilities.

Fortunately caffeine can be had in many forms, so you do not need to be a coffee lover to feel the effects.

Of which, one of them is fat loss, as such, it is a popular addition to many supplements.



[2] Committee on Military Nutrition Research. Caffeine for the sustainment of mental task performance. Formulations for military operations. Washington: National Academy Press; 2001. pp. 61–65.

[3] Caffeine lowers perceptual response and increases power output during high-intensity cyclingDoherty M, Smith P, Hughes M, Davison R. J Sports Sci. 2004 Jul;22(7):637-43.

[5] Eskelinen M.H., Ngandu T., Tuomilehto J., Soininen H., Kivipelto M. Midlife coffee and tea drinking and the risk of late-life dementia: a population-based CAIDE studyJ. Alzheimers Dis. 2009;16(1):85–91. doi: 10.3233/JAD-2009-0920.

[6] Caffeine as an attention enhancer: reviewing existing assumptions. Einöther SJ, Giesbrecht T. Psychopharmacology (Berl). 2013 Jan;225(2):251-74. doi: 10.1007/s00213-012-2917-4. Epub 2012 Dec 16. Review.

[7]  1995;39(3):135-42.Comparison of changes in energy expenditure and body temperatures after caffeine consumption. Koot P, Deurenberg P.


[8] Rush JW, Spriet LL. Skeletal muscle glycogen phosphorylase a kinetics effects of adenine nucleotides and caffeineJ. Appl. Physiol. (1985). 2001;91(5):2071–2078.

[9] The effects of caffeine and exercise on body weight, fat-pad weight, and fat-cell size. Wilcox AR. Med Sci Sports Exerc. 1982;14(4):317-21.

Caffeine benefits and risks
Article Name
Caffeine benefits and risks
We look at the benefits and risks of the worlds drug of choice.

Ben BA(Hons), PGCert

Ben established this site to be a free resource in 2015. Since then it has gained over half a million visits. He has always been interested in sport and he started playing rugby at the age of 6 represented his town, county and school. Ben also enjoys cycling, has started skiing and is in the Army Reserve representing his Regiment as part of the 150 Regimental Shooting Team. He holds a bachelor's and postgraduate degree in sport exercise & nutrition.

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