CP+R Sciencecast | Edition #160
Wednesday 9th April 2024
Common questions + misconceptions about coffee
A new research paper on caffeine came out last week which covered 14 of the top questions and misconceptions about caffeine. I’ve picked out 6 that you might find interesting below and give the research paper a read if you’d like to swat up on the other 8.
Caffeine is probably the world’s most consumed performance-enhancing drug. It’s one of the few substances that consistently enhances various aspects of performance from psychological alertness and reaction time to muscular strength, power and endurance.
Here are those 6 common questions and misconceptions…
Does caffeine dehydrate you?
A fairly common statement you hear right? Historical research suggested that a dose of more than 300mg of caffeine (2-3 cups of coffee) may induce acute diuresis (more urine output). However, recent research examining and controlling for multiple factors has questioned that and has shown that moderate daily doses of caffeine (250-300 mg) do not increase urine volume and only in excessive amounts which is over 500mg or more than 5 cups of coffee is an issue.
Does caffeine promote fat loss?
The potential science behind this is that there’s an association between caffeine and fat oxidation and metabolism. However, the data as to if that actually leads to more body fat losses is very messy and doesn’t seem to show anything conclusive so, I’d place your time and efforts elsewhere.
Does caffeine work for everyone?
There is clear evidence here that large inter-individual variability exists. Exactly who is and who isn’t affected based on sex and/or genetics isn’t clear and so, understanding how your own body responds is key.
“Coffee’s hidden health benefits with James Hoffmann & Professor Tim Spector”
from ZOE Science and Nutrition
Does habitual caffeine consumption influence your response?
This is one I definitely had down as true. However, similar to dehydration, the classic study that showed a potential mechanism hasn’t been repeated in humans or in more recent studies on responses. The majority of studies didn’t report habitual intake very well so, more research is needed on this one.
Does waiting 90 mins after waking to consume caffeine help you avoid the afternoon “crash”?
Now, this wasn’t really on my radar but apparently, it has been all over social media with influencers claiming that drinking your coffee first thing is ‘ineffective’ and delaying it by 90 minutes not only is more effective but also, prevents an afternoon “crash”.
The research shows both of these are untrue so, don’t worry about putting a stopwatch next to your kettle and enjoy it at your leisure.
Does caffeine cause heart problems?
This is an interesting one as it’s important to disassociate caffeine from the form we most commonly consume, which is coffee.
Coffee consumption has been shown to have a number of cardiovascular and metabolic benefits due to its high polyphenol and fibre content.
Caffeine on the other hand, we know can acutely increase heart rate and systolic blood pressure and therefore, could potentially exacerbate pre-existing cardiovascular conditions such as angina and atrial fibrillation.
Take-homes:
Given the significant individual response to caffeine, it’s tough to give a sweeping recommendation. That said a decent starting point would be that for most people, anything up to the FDA guidelines of 400mg (4 cups of coffee) per day would be fine. If you feel like you’re a bit more sensitive to caffeine or perhaps are managing angina, high blood pressure or atrial fibrillation then, aiming for 2 or fewer cups would be a good idea.
That said if you’re looking to maximise the health benefits of coffee then, decaff has been shown to be just as beneficial. So rather than going cold turkey, I’d advise switching all or some of your cups to decaff.
Thank you for reading.
Best wishes,
Matt Thompson
Head of Cardiac Exercise
