High levels of caffeine consumption is becoming more and more prevalent within the fitness community and the general public. Caffeine is the most widely used drug that promises increased energy, improved mental clarity and elevated physical and psychological performance.
There is a huge driving force in society to perform at a high-level; be it physically in the gym or on the field or court, or mentally at work in the office or on the job site.
When it all gets too much many of us reach for that conveniently packaged energy drink, consume our pre-workout supplement of choice, or pop a couple of caffeine pills.
But could our morning ‘buzz’ and afternoon ‘pick-me-up’ be doing us more harm than good? Let’s delve into the depths of caffeine and its affects to find out!
What Is Caffeine?
Caffeine is a potent central nervous system (CNS) and metabolic stimulant, and is the world’s most widely consumed psychoactive drug. Caffeine works as a powerful stimulant to improve physical and mental performance by means of antagonizing adenosine receptors, causing alertness and wakefulness.
Naturally, caffeine is found in the leaves, seeds and fruits of over sixty plant species including coffee, tea and yerba mate, with the most common form being the ‘bean’ of the coffee plant. Caffeine is also synthesized in laboratories and used in soft drinks and energy drinks, caffeine tablets, and in many pre-workout and fat loss supplements.
The table below outlines the typical amount of caffeine found in some common beverages.
Tea (Tea Bags)
Soft Drink/Diet Soft Drink
Fat Burner/Thermogenic Supplement
Regular use of caffeine can quickly lead to tolerance and dependence, with some individuals beginning to experience dependence in as little as 7 days at doses as low as 150mg per day (around the same amount of caffeine found in a large cup of coffee or standard energy drink).
Over time the positive performance effects associated with caffeine consumption will diminish as the body produces more and more adenosine, with eventually caffeine tolerance becoming too great to overcome regardless of how much is consumed. Fortunately, a 4 week break from caffeine will re-sensitize most individuals to the effects of caffeine at a much lower dosage.
However, completely removing the consumption of caffeine will result in withdrawal type symptoms ranging from headaches to muscle stiffness and irritability, and will also lead to drowsiness and decreased performance for 3-6 days following the cease of consumption.
Therefore, those looking to reduce their daily caffeine consumption are best served doing so very gradually. As a rule of thumb removing 50mg-100mg of caffeine per day over a period of 5-10 days will reduce the severity of the associated withdrawal symptoms from caffeine.
What Are The Different Forms Of Caffeine?
Just as caffeine is found in a variety of beverages and products from coffee to energy drinks, soft drinks and chocolate, caffeine in its chemical form can also be categorized into naturally occurring forms and a variety of synthetic forms each with subtle differences and effects.
Caffeine is found naturally in around 60 plant varieties, with the most renowned natural sources being coffee and various teas including black, green and yerba-mate teas. These naturally occurring sources of caffeine often contain a variety of botanicals, antioxidants and other naturally occurring compounds that provide their own health benefits whilst working synergistically with the caffeine to provide a ‘balanced’ energy lift.
In comparison to the limited number of plants yielding natural caffeine, there are literally hundreds, if not thousands of energy drinks, pre-workout supplements, soft drinks and foods that contain synthetic forms of caffeine. Synthetic caffeine is produced in laboratories for the sole purpose of adding an artificial energy uplift to a variety of products. It may also be argued that adding caffeine to consumable products may also make them addictive.
Synthetic caffeine is chemically exactly the same as its natural counterpart, however synthetic caffeine is produced in isolation and therefore does not contain the naturally occurring botanicals and antioxidants found in natural caffeine that work to balance and regulate the body’s response to the properties of caffeine.
Typically, synthetic forms of caffeine will be absorbed into the bloodstream much faster and in higher concentrations than the naturally occurring variety. The result is a quicker and more ‘harsh’ spike in energy synonymous with energy drinks and pre-workout supplements, followed by a more intense ‘crash’ or down-regulation of the energy effects of caffeine.
In an effort to improve on simple forms of synthetic caffeine and address the demand for energy products without the harsh ‘crashing’ effects, some pre-workout supplements and energy drink manufacturers are seeking new altered synthetic alternatives. Companies are turning to new caffeine-hybrids that contain bonded forms of caffeine and nature-identical ingredients that in theory can provide longer lasting energy, offer health benefits beyond those of caffeine alone, and deliver the same energy enhancing effects of caffeine in significantly lower dosages.
One such product, PURENERGY (Caffeine Pterostilbene Complex) is a patented innovative ingredient developed by ChromaDex that combines caffeine (43% proportion) with pTeroPure (57% proportion), a 99% pure nature-identical pterostilbene.
Pterostilbene is a naturally occurring antioxidant produced by plants to protect themselves from viral, bacterial and fungal attacks and is most abundant in blueberries. Pterostilbene has the unique ability to change abnormal cellular metabolic pathways by up or down-regulating these pathways based on the nature of the disease and ageing process.
PURENERGY is a next-generation caffeine alternative that delivers almost 30% more caffeine into the bloodstream than ordinary caffeine, with the rate of caffeine absorption being approximately 30% slower. In addition the half-life of caffeine from PURENERGY is extended significantly by around 25%; 6 hours following oral consumption subjects taking PURENERGY continued to experienced improved energy, reduced fatigue and greater concentration than baseline.
Similarly Infinergy (Di-Caffeine Malate) is a patented ingredient developed by innovative supplement ingredient supplier Creative Compounds. Infinergy is a precise combination of caffeine and malic acid fused together using an ionic bond into a compound known as di-caffeine malate.
Infinergy contains approximately 75% caffeine and 25% malic acid by molecular weight. The malic acid in Infinergy works to buffer the salts in caffeine, allowing for easier digestion whilst also replenishing the energy produced by caffeine, which helps to minimise the excessive “jitters” side effect that many users experience with caffeine anhydrous and the dreaded post-caffeine energy ‘crash’.
What Are The Effects Of Caffeine On The Adrenal Glands?
Perhaps the biggest concern surroudning excessive caffeine consumption over long periods of time is its effect on cortisol and the adrenal glands, and potential to cause syndromes such as adrenal fatigue.
The adrenals are glands on top of the kidneys that release hormones including cortisol that trigger the ‘flight-or-fight’ response when presented with external stressors such as pollutants, toxins, poor health, or stressful and life-threatening situations. The problem with caffeine is that it stimulates the adrenal glands in much the same way as any other stressor. As an individual starts to increase their caffeine consumption and frequency of consumption throughout the day the adrenal glands become overworked, producing more and more cortisol, and begin to burn out.
The combination of excessive caffeine consumption in addition to daily stressors causes over stimulation of the adrenals and a decrease in various regulatory hormones that maintain the body’s homeostasis. This biological response has been titled “adrenal fatigue” and results in a variety of issues including feelings of exhaustion, trouble getting out of bed regardless of hours slept, uncontrollable cravings of sweets and salty foods, decreased libido, increased body fat, slower recovery from training and increased frequency of illness.
Another undesirable side-effect of excessive caffeine consumption is its influence on the natural cycle and production of cortisol and its subsequent connection with weight-gain, low immunity, fatigue and insomnia. Typically natural cortisol production is at its highest in the early morning to help with the natural waking cycle, however those who become over-reliant on caffeine throughout the day effectively rewire this process.
The chronic exposure to caffeine and release of cortisol forces the body into a continual ‘state of alert’ whereby regenerative processes such as sleep and natural anabolic systems no longer operate at their full capacity, resulting in loss of energy and fatigue. This release of extra cortisol from caffeine throughout the day can contribute to such conditions as chronic inflammation, allergies, insomnia and conservation of body fat and fluid that hinder fat loss and muscle retention.
When caffeine use throughout the day stimulates the release of cortisol, there is a cortisol-induced demand for increased blood sugar and an increase in the release of insulin to facilitate the movement of glucose from the bloodstream into cells, putting the body in a state of alert to deal with the physical danger it believes will be encountered.
The body is unable to detect the difference between true physical stress and or the release of cortisol from caffeine whilst sitting at a desk-job, and as such the released blood sugar (glucose) is not actively burnt-off and weight-gain, particularly around the organs and mid-section, is a likely result. In addition muscle tissue and other cells become resistant to the effects of insulin, making it even more difficult to effectively utilize carbohydrates (glucose) as energy, leading to elevated levels of blood sugar, increased body fat and the potential for type 2 diabetes.
What Effects Does Caffeine Have On Sleep?
The effects of caffeine on sleep quality are both dose-dependant and time-dependant and pertain to an individual’s overall caffeine tolerance. Caffeine has been demonstrated to disrupt sleeping patterns particularly when ingested close to bedtime in doses greater than 200mg, resulting in the delayed onset of sleep, reduced total sleep time as well as altered stages of sleep resulting in a reduction in overall sleep quality.
Removing late night consumption of caffeine may appear to be a simple fix for improving sleep quality, however new research is showing that regular daily caffeine consumption also results in significantly diminished sleep quality due to the disruption of the body’s internal clock, known as the circadian rhythm.
The circadian rhythm refers to a number of natural biological processes that occur in the body on a 24 hour cycle, allowing individuals to coordinate their behaviours (such as sleep) with the daily environmental changes of the day-night cycle. An individual’s sleep quality and overall well being is dependant on the circadian rhythm working correctly and remaining synchronized with night and day.
Of most interest is caffeine’s effect on the production of melatonin, a natural hormone that is secreted during the end of the day to promote restfulness and sleep when less natural light is available. Regular caffeine use appears to effectively delay the natural release of melatonin by up to 40 minutes, making sleep less inviting and delaying the body’s natural cycle which can impact morning wakefulness.
Individuals suffering from irregular circadian rhythm will likely experience some hormonal irregularities that can lead to obesity, poor cognitive skills, reduced physical recovery and immune deficiencies.
How Much Caffeine Is Too Much?
It is extremely difficult to determine exactly how much caffeine per day is too much. The effects of caffeine on the body will vary dramatically between individuals, depending on their biological tolerance and other aspects of their life such as sleep, recovery, diet and training that may help reduce the unwanted side effects of excessive caffeine consumption.
With this in mind, it appears that up to 400mg of caffeine per day would not raise safety concerns for most healthy adults. To put this in perspective, 400mg of caffeine is the equivalent of 3-4 cups of coffee, 2 and a half 500ml energy drinks or 1.5-2 scoops of most pre-workout or fat loss supplements.
How much caffeine an individual can consume in a single dose will also depend on one’s sensitivity to caffeine and the magnitude of effect that is to be achieved. Typically a single dose of 150mg-200mg of caffeine or 2-2.5mg/kg of bodyweight is likely to produce the desired anti-fatigue and cognitive enhancing effects without producing relevant changes to blood pressure, blood flow or body temperature.
Many of the benefits associated with caffeine consumption, particularly its impact on adrenalin and hence mental focus and physical performance will fade with tolerance. Therefore individuals using caffeine for its performance benefits would be best using caffeine either sporadically when maximum performance is important, or in a cyclical manner, alternating between specific periods of use followed by specific periods of abstinence.
Because of individual tolerance, caffeine cycling protocols for physical performance can be problematic to recommend, however a starting point could be to use caffeine from Monday to Friday (5 days) followed by abstinence for 9 days, before beginning another Monday to Friday (5 day) cycle. Similarly, performance and strength based athletes preparing for an important competition, may wish to reduce or even cease caffeine consumption for several days prior to a competition to increase its effectiveness on the day of the contest.
The Verdict On Caffeine
The majority of research on caffeine tends to focus on the narrow range of caffeine’s short-term benefits to athletic and cognitive performance, with little information on the long-term health and performance implications.
Caffeine’s short term effects are certainly desirable for the competitive bodybuilder or athlete seeking optimal physical performance, or for the everyday office worker after increased productivity and enhanced cognition.
In contrast little research exists pertaining to the long-term health effects of caffeine use, with most arguments against the use of caffeine citing only the withdrawal symptoms rather than the direct long-term implications on health, cortisol and sleep quality.
With ever-increasing quantities of caffeine being consumed by a variety of subcultures, such as bodybuilding and fitness enthusiasts, workaholics and those ‘plugged-in’ 24/7, the overall research on long-term caffeine consumption is unsatisfactory.
It therefore appears that at this point in time the best approach to caffeine consumption would be “everything in moderation”