So, high caffeine, what are the risks? Firstly, the dosage will be quantified, as this is a significant contributor when discussing risk.
The tolerance of the consumer matters a lot in this regard, as I’m also sure the biomass also matters when it comes to absorption and tolerance levels.
General Information
The FDA have stated that 400mg of caffeine as a daily intake is safe for most people, however, this figure will need to be adjusted for different sizes and body types.
What someone may prefer, is to 3mg of caffeine per kilo of bodyweight as a guideline for safe consumption levels, though this can be pushed to 6mg per kilo.
For example, if we use 3mg/kg, and we have someone who is 60kg, then this could suggest a safe limit of 180mg, depending on tolerance levels.
The best way to measure tolerance levels, is to monitor your response, such as heart rate, blood pressure, and even jitters, which may occur at higher dosages.
Caffeine has been associated with cardiovascular strain if consumed at high dosages regularly, and when coupled with strenuous exercise.
Pre-workouts often include very high levels of caffeine, relative to other sources such as energy drinks, or coffee.
As an example, I have recently tried pre-workouts shots from Optimal Nutrition, and C4, and there are differences between the products.
For instance, the Optimal Nutrition Gold Pre-workout shot contained 175mg of caffeine, whereas the C4 original pre-workout shot contained 150mg of caffeine.
These dosages are similar to most energy drinks, such as Monster Energy, Relentless, and the larger Red Bull cans etc.
Arguably, consuming one of these on their own, and a smaller dose later in the day (at least 6 hours or more before sleep) is relatively safe.
It is usually recommended to not consume additional sources of caffeine, if consuming a pre-workout.
It should also be noted that the tingling sensation induced from pre-workouts is not from caffeine, rather, it is from beta-alanine.
The Risks
Daniel Amen had reported that caffeine, typically in daily doses higher than 100mg, has been associated with shrinkage of the brain.
Of course, Amen recommends that if people are going to consume caffeine, they need to keep it below that level (not possible if you want to consume a pre-workout)
Caffeine has also been associated with gradual memory decline when consumed at higher dosages, in the following article, the association was established when 6 or more coffees were consumed (this is approximately 600mg of caffeine, and is considerably above the safe level advised by the FDA:
I quote from the article: “In the largest study of its kind, researchers have found that high coffee consumption is associated with smaller total brain volumes and an increased risk of dementia“.
Other risks include slowing down detox pathways, by competing for enzyme binding, specifically, the CYP1A2 enzyme. Caffeine can impact mineral absorption (Calcium, Magnesium, Iron etc), and can also affect hydration, as its a diuretic.
Alternatively, lower dosages have been associated with a reduction in memory decline, I have provided a citation to a study: Chen JQA, Scheltens P, Groot C, Ossenkoppele R. Associations Between Caffeine Consumption, Cognitive Decline, and Dementia: A Systematic Review. J Alzheimers Dis. 2020;78(4):1519-1546. doi: 10.3233/JAD-201069. PMID: 33185612; PMCID: PMC7836063.
The link is here: https://pubmed.ncbi.nlm.nih.gov/33185612/
I quote from the conclusion from the study: “This review suggests that caffeine consumption, especially moderate quantities consumed through coffee or green tea and in women, may reduce the risk of dementia and cognitive decline, and may ameliorate cognitive decline in cognitively impaired individuals.”
Summary
A moderate amount of caffeine can provide some health benefits, this will be the level where someone doesn’t experience negative side-effects, and will vary from person to person; on the other hand, higher dosages are associated with various health risks, from cardiovascular issues, to memory decline etc.