Tea and coffee have been staples in our diet for centuries. Many of us consume it without a second thought, but have you ever considered the good and bad health effects of caffeine? Is there a value for athletes and gym-goers using caffeine as an ergogenic aid? Is too much coffee dangerous for your health? Finally, is there really any value to utilising caffeine as weight loss supplements? Read on to see what research-based science says about caffeine benefits & side effects!

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How does caffeine work?

If you’re interested in getting an insight into the fascinating science around caffeine and how it keeps the droopy eyes at bay, read how does caffeine work. This link opens in a new tab and it’s a quick read which I guarantee you won’t regret!

Caffeine benefits

Caffeine as a weight loss supplement: Many dieters consume weight loss and caffeine pills to lose weight, while other people rely on regular tea and coffee. Caffeine consumption leads to an increase anywhere from 3-11% in resting metabolic rate. The higher your metabolic rate is, the more calories your body burns. Unfortunately for obese people, the rate of fat burning that occurs based on metabolic rate is lower than for a lean person. A study observed fat burning rates of up to 29% in lean people, while only a 10% increase in fat burning was observed in obese people.

There is, however, a clause that needs to be highlighted. The body over time can become accustomed to regular caffeine consumption. Consequently, the increased metabolic rate and associated fat burning effects can diminish over long periods of time. You can reduce this tolerance by engaging in caffeine cycling which involves periods of abstaining from caffeine altogether, e.g. 2 weeks no caffeine followed by 2 weeks consuming caffeine.

Saying that, all hope is not lost as caffeine has been shown to suppress appetite. So whenever you feel like grabbing the nearby bar of chocolate or diving into the fridge, first opt for a cup of tea or coffee.

Caffeine and exercise: Anyone with a keen interest in sports and working out will likely consume caffeine as a pre-workout supplement. This is why it makes my top 5 bodybuilding supplements. Many people often consume a pre-workout caffeine supplement to enhance their performance. If you’re interested in reading about caffeine pills and other caffeine supplements, check out do healthy caffeine supplements exist?

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Caffeine has been proven to decrease rates of perceived exertion, making the workout feel somewhat easier. Additionally, since caffeine reduces fatigue, the number of reps and power output is elevated, meaning you can exert extra reps when compared with no caffeine ergogenic aid. A study observed an increase of 11.60% reps on the bench press and 19.10% when completing leg presses, which is rather impressive, especially when nearing failure!

Caffeine and feeling good: If you took the time to read how does caffeine work, you’ll know that caffeine aids in releasing dopamine, also known as they feel-good chemical. So if you experience elevated feelings of joy after drinking your caffeine beverage (or food) of choice, you now know why! As a result of this dopamine release, evidence has suggested that caffeine consumption may reduce the rates of suicide when 2-4 cups of coffee are consumed daily.

Miscellaneous caffeine benefits:

  • A meta analysis study has identified positive protective effects from liver cancer.
  • A separate meta analysis study concluded that reduced risk of death from all causes was observed in people who consumed 2-4 cups of coffee a day.
  • Other studies suggest that caffeine may offer protection against type 2 diabetes, Parkinson’s disease and strokes

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    Caffeine adverse effects

    The recommended daily limit dose of caffeine is 400 mg. Exceeding this recommended value is typically where the bad health effects of caffeine are observed. Want to know are you consuming too much caffeine? Check out what does 400 mg of caffeine consumption look like?
    Caffeine addiction and withdrawal: With all the above benefits of caffeine, it’s not surprising that caffeine is highly addictive. Sometimes people don’t realise that caffeine is a psychoactive drug, meaning it increases activity in the central nervous system, namely the brain. These effects are in fact similar to the effects observed following cocaine consumption! With this elevated alertness follows feelings of increased productivity. Caffeine also releases dopamine making us feel good, which is another factor which contributes to the addictiveness of this stimulant.

    Caffeine withdrawal can lead to a range of symptoms, including:

    • Headache
    • Tiredness
    • Irritability
    • Low mood
    • Fatigue

    Insomnia: We are all now aware of the value caffeine has in terms of reducing fatigue and increasing alertness. With this in mind, it’s no wonder that many people experience difficulties sleeping. Caffeine has a half-life of anywhere from 5-8 hours depending on the caffeine dose and individual factors such as caffeine tolerance, weight and pregnancy. This means traces of the stimulant could remain in your system when you’re trying to sleep, even if your last caffeine consumption was earlier in the day.
    Anxiety: The effect of caffeine on anxiety symptoms can be attributed to elevated feelings of alertness arising from increased adrenaline release. This fight or flight response can be increasingly pronounced in individuals and result in increased nervousness and anxiety. One study observed a greater than twofold increase in stress amongst male participants who consumed a 300 mg serving of caffeine (equivalent to approximately 2 cups of coffee). Surprisingly, these effects prevailed in both light and habitual caffeine consumers.

    Muscle breakdown: Negative health effects of caffeine in terms of reduced muscle growth have been observed in people where excess caffeine is consumed. This condition, known as rhabdomyolysis, causes damaged muscle fibres to enter the blood stream. While the cases attributed to excess caffeine consumption are relatively rare, some instances have been observed, e.g. in a 21-year-old male who consumed 450 mg caffeine (approximately 3 large cups of coffee) 30 minutes before exercise.

    Miscellaneous caffeine adverse effects:

    • High caffeine consumption has been linked to a temporary elevated blood pressure, which would be a concern for individuals currently diagnosed with high blood pressure.
    • Caffeine consumption has also demonstrated elevated heart rates in some people and can also lead to an irregular heart beat, known asatrial fibrillation. This condition has been observed in young individuals who consume energy drinks which typically have a very high caffeine content.
    • With an increase in alertness and energy comes an inevitable feeling of fatigue for many people once the caffeine leaves their body. While this could be counteracted by maintaining caffeine in your system throughout the day, this could ultimately result in disrupted sleep and consequently feeling tired.


    • When consumed in moderation, caffeine can provide some excellent health benefits
    • Caffeine is an excellent ergogenic aid to enhance performance during exercise
    • People using caffeine for weight loss/fat burning may only see short-term benefits as their body becomes used to caffeine
    • Excess caffeine can cause insomnia, fatigue, elevated heart rate and lead to addiction
    • Caffeine cycling and adhering to the daily caffeine dose limit of 400 mg can minimise negative health effects of caffeine

    What’s your opinion on caffeine? Do you think the benefits outweigh the disadvantages? Have you ever felt addicted to caffeine or do you frequently opt for the decaf beverages? I’d love to hear your opinion in the comments below!

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    Da Silva VL, Messias FR, Zanchi NE, Gerlinger-Romero F, Duncan MJ and Guimarães-Ferreira L. (2015) Effects of acute caffeine ingestion on resistance training performance and perceptual responses during repeated sets to failure. J Sports Med Phys Fitness, 55(5):383-9.

    Felman, A., 2019. Caffeine: Effects, Risks, And Cautions. [online] Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/271707#benefits [Accessed 16 March 2020].

    Gunnars, K., 2018. Can Coffee Increase Your Metabolism And Help You Burn Fat?. [online] Healthline. Available at: https://www.healthline.com/nutrition/coffee-increase-metabolism#section2 [Accessed 16 March 2020].

    Johnson, J., 2018. How Long Does Caffeine Stay In Your System? Metabolism And More. [online] Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/321784#how-long-does-it-take-to-metabolize-caffeine [Accessed 16 March 2020].

    Lane, J., Adcock, R., Williams, R. and Kuhn, C., 1990. Caffeine effects on cardiovascular and neuroendocrine responses to acute psychosocial stress and their relationship to level of habitual caffeine consumption. Psychosomatic Medicine, 52(3), pp.320-336.

    Matthews, M., 2018. How Much Does Caffeine Actually Help Your Workouts? – Legion Athletics. [online] Legion Athletics. Available at: https://legionathletics.com/how-much-caffeine-to-help-workouts/ [Accessed 16 March 2020].

    Spritzler, F., 2017. 9 Side Effects Of Too Much Caffeine. [online] Healthline. Available at: https://www.healthline.com/nutrition/caffeine-side-effects [Accessed 16 March 2020].

    Sung, D. J., Choi, E. J., Kim, S., & Kim, J. (2018). Rhabdomyolysis from Resistance Exercise and Caffeine Intake. Iranian journal of public health47(1), 138–139.

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    Lisa · 16/03/2020 at 6:29 PM

    Hi Sharon,

    Thanks for this great article. I admit I knew a few of the benefits and side effects of caffeine before reading your post, but you’ve opened my eyes to some new ones too!

    For years I was particularly sensitive to caffeine and found it triggered migraines, but I also found one day that a cup of coffee just as the migraine was starting could also stop the migraine in its tracks! Conveniently I seem to have grown out of caffeine induced migraines now, as I tend to use it as a pre-workout boost.

    I was not aware of the risk of muscle breakdown from excessive caffeine consumption, its definitely something I’ll have to keep a close eye on as I do occasionally get in the habit of using caffeine to stay alert for long shifts at work. I have heard of adrenal fatigue being associated with ongoing excessive caffeine intake, particularly among those trying to lose weight – is this something that you’ve encountered in your research?

    Thanks again for a great post!

      Sharon · 17/03/2020 at 7:40 AM

      Hi Lisa,

      Good to hear you learned something new from the article. That is interesting, I wonder is there much research correlating migraines or migraine-relief and caffeine?

      With regards to adrenal fatigue, I have encountered it in some reports. As you stated, it’s supposed to be caused by excess caffeine consumption. Although, I’ve read other peer=-reviewed studies that refute the existence of this as a medical condition. Either way, a person experiencing the symptoms that adrenal fatigue supposedly elicit should visit to a health professional to diagnose the cause. I would love to hear your thoughts on it.

      Best wishes,

    Justin · 16/03/2020 at 6:39 PM

    Wow, very interesting. I wasn’t aware that caffeine had so many health benefits in moderation. I understood that too much caffeine could affect your sleep but not the other adverse reactions.
    Thank you for highlighting these benefits and how best to avoid the adverse reactions.

      Sharon · 17/03/2020 at 7:48 AM

      Hi Justin,

      Yes it really does have some tremendous advantages. In terms of adverse effects, I’d agree with you on the sleep disruption, for me at least, that would be the primary issue I would experience with caffeine consumption.

      Hope the article helps!

    Telly · 16/03/2020 at 8:40 PM

    Very interesting article I did not know that caffeine had so many benefits.This article open my eyes to better ways to use caffeine.I will defiantly share this with other people.

      Sharon · 17/03/2020 at 7:49 AM

      Hi Terry,

      You’re right, it really is a wonder product, it’s nice to be able to have some vices that are healthy.

      Please do share it, you never know how it could improve their health, e.g. sleep etc.


    Bob · 16/03/2020 at 9:30 PM

    Caffeine has always given me that extra jolt to work out longer & harder at the gym, as well as work harder in the office. I’ve never had any bad effects from caffeine & the befits it gave me have helped me in all my endeavors.
    Thanks for the information.

      Sharon · 17/03/2020 at 7:54 AM

      Hi Bob,

      I’m delighted to hear you’re not experiencing adverse effects from caffeine. All too many people consume excess caffeine which ends up disrupting their sleep and wreaking havoc on their health.

      Best wishes,

    Jeff · 17/03/2020 at 5:00 PM

    This is an awesome article on caffeine providing us the benefits and the side-effects it is very useful for us to use caffeine in a safe and healthy way. The majority of Americans abuse caffeine just like alcohol and other drugs, we are ruining our lives depending on caffeine to the point we are abusing its benefits by overconsuming

    Thank you

      Sharon · 17/03/2020 at 8:03 PM

      Thank you Jeff,

      It’s unfortunate that caffeine is so addictive, although it is the lesser of evils when compared with the likes of alcohol and drugs. It seems as if people aren’t able to moderate their consumption of foods etc.


    John · 17/03/2020 at 6:26 PM

    Great article! Thanks for creating such a concise collection of costs and benefits of caffeine consumption. As a habitual coffee drinker myself it’s good to know the limit (400mg a day) and I love the idea of coffee cycling.
    I’m actually going to try and do one day off two days on for starters. The idea of 2 weeks off without coffee scares me too much at this point lol!

      Sharon · 17/03/2020 at 8:09 PM

      Hi John,

      You are most welcome. I would love to hear how you get on with the caffeine cycling. Some people practically crash for the first few days/weeks while they body adjusts to the lack of caffeine in their system. Some people also fear the cold turkey approach and wean themselves off it, which is sometimes more manageable.

      Best of luck either way!

    Velislav · 17/03/2020 at 7:29 PM

    Great article. I was recently looking for some info from this kind in order to help my self with my condition. I’ll defenetelly try those pills and i hope the will help me. THANK YOU!

      Sharon · 17/03/2020 at 8:10 PM


      You’re very kind, thank you! Let me know if I can be of assistance with any queries you may have!


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