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Hey everyone welcome back to the barbell medicine youtube channel where we bring modern medicine to strength conditioning and strength and conditioning to modern medicine i’m your host dr jordan feigenbaum and this episode is all about caffeine caffeine is widely used in the united states as a recent survey reports that 85 of the population consumes at least one
Caffeinated beverage per day the average intake is about 165 milligrams per day which is about two cups of coffee or four cups of tea whereas the 90th percentile for caffeine intake is reported to be about 380 milligrams per day or four cups of coffee given the prevalence of caffeine use it should come as no surprise there’s a ton of research out there that’s
Going to help answer our questions on this particular topic caffeine works in multiple ways many of which haven’t been fully fleshed out for example there are a number of findings from animal models in isolated tissue studies which is basically looking at how caffeine works on single muscle fibers that really haven’t been replicated in human studies in any case
Based on existing evidence we can only say that caffeine tends to do the following things in humans so thing one it increases calcium release in the muscle tissue so that’s cardiac muscle skeletal muscle and smooth muscle which results in a number of actions such as increased muscle contraction force potential and increased muscle excitability it also inhibits
Phosphodiesterase enzymes to increase intracellular cyclic amp and cyclic gmp which basically have many different actions they’re secondary messengers and it changes the cell’s excitability and function it also blocks adenosine receptors with varying potency at each receptor it increases norepinephrine release from the sympathetic nervous system basically your
Fight or flight catecholamines overall there are a number of mechanisms that caffeine uses though again they’re not fully understood at present the increase in excitability of the muscle tissue via caffeine-induced calcium increase appear to play a significant role the current recommendation regarding safety of caffeine intake basically states that caffeine
Intakes up to 400 milligrams per day which is about four to five cups of coffee is safe for healthy non-pregnant adults and generally does not produce negative side effects to that end regular caffeine ingestion appears to be well tolerated and does not appear to be reliably related to disease overdoses are exceedingly rare as well as the ld50 which stands for
The lethal dose 50 the dose needed to kill about 50 of the test population is about 150 to 200 milligrams per kilogram body weight or 75 to 100 cups of coffee for 70 kilo 154 pound adult depending on individual sensitivities a few important things to note regarding caffeine and health so first off caffeine intake does increase the force of each heartbeat but
Tends to not actually increase heart rate in most individuals with respect to blood pressure many folks will say that drinking caffeine or coffee increases blood pressure although we don’t see that in habitual consumers so people who drink caffeine or consume coffee regularly although you do tend to see a small increase in it uh in caffeine naive individuals
And those who are very very sensitive to it in case you were wondering yes coffee does tend to increase urine production and urine frequency at doses of 250 to 300 milligrams of coffee per day and same thing with gut motility so you might have to go with respect to specific diseases there are a number of studies suggesting that regular coffee intake may reduce
The risk of heart attack also diabetes and some cancers even at relatively high intakes greater than four cups per day in that same breath however there are also other studies suggesting no risk reduction with these diseases with regular coffee consumption though again there aren’t really studies showing an increased risk with increased coffee consumption and
Again not all caffeine comes from coffee which makes it hard to confidently describe the relationship of caffeine intake with all these potential disease states so overall the existing literature suggests that moderate to even high intakes of caffeine 400 to 600 milligrams of caffeine per day is not associated with any increase in cardiovascular disease risk
Cardiac arrhythmia any increased risk of heart failure or high blood pressure or even blood pressure changes and those who regularly consume caffeine as mentioned before consumption of moderate amounts of caffeine is associated with an actual reduction risk of cardiovascular disease although that is complicated because again coffee and caffeine are not the
Same thing there might be multiple things at play there taken together i feel pretty comfortable in saying that habitual caffeine or coffee intake is unlikely to be the smoking gun with respect to developing any particular disease like cardiovascular disease cancer diabetes etc provided the person tolerates it well but it’s probably not saving anyone’s life
Either i think the biggest potential health risk from caffeine intake or coffee intake probably has to do with individuals sleep patterns now this is a very complex relationship when you actually look at the literature there are unreliable findings with respect to caffeine intake dosing and timing relative to time to sleep and how that actually affects sleep so
I don’t want to say that there’s any one particular you know sort of relationship here it does appear that in westernized societies that timing people’s caffeine intake very close to bedtime so even up to six hours before bed may negatively impact their sleep that night they call we call it this coffee cycle so effectively you drink coffee because it improves
Your performance which we’ll talk about shortly and then you go through a period of coffee deprivation which is during the day and during sleep and that actually you know maybe affects your sleep overnight in a negative way and you wake up in the morning and you’re more fatigued and so you drink more coffee that relationship again is very complex however
So it appears that many individuals can consume coffee with really no impact on their sleep it also appears that you might need some additional triggers to reduce your actual sleep quality or sleep quantity and so overall i think there needs to be this sort of individual assessment based on how folks actually respond to caffeine my general advice is to avoid
Anything with caffeine in it about six to eight hours prior to bed unless you’ve again previously tolerated it well and it doesn’t affect your sleep quantity so how much you’re sleeping and sleep quality and again this is really complex so i wouldn’t go around saying that caffeine negatively affects your sleep i think it’s highly individualized and very very
Complex check out the study by o’callaghan about sleep and caffeine intake and you can start to get a better appreciation of just how complex this issue is there are many different ways to administer or deliver caffeine so let’s talk about the different ways first up is caffeine gum there is a markedly faster rate of absorption with gum compared to other ways
Of administering caffeine for example when you use a 200 milligram dose they see a very large increase in plasma caffeine concentration so caffeine in your blood between 5 and 15 minutes after ingesting it uh capsules basically the largest increase in caffeine concentration seen in the blood is seen about 25 to 45 minutes after consumption so slower than gum
You can also do mouth rinsing so swish and spit of caffeine is relatively new you don’t actually swallow the solution but you kind of swirl it around your mouth for about five to twenty seconds unfortunately data looking at blood levels of caffeine report no increases in blood caffeine concentration so it doesn’t actually appear that this necessarily works
Although people are trying this energy drinks this is a huge topic and people are very very interested a number of studies have actually investigated the effects of commercially available energy drinks such as red bull which basically contains 160 milligrams of caffeine two thousand milligrams of taurine and about 10 grams of glucose per 500 cc’s while caffeine
Is shown to potentially improve performance and isolation the current report on energy drinks shoulder shrug because it has all these different things in it and it doesn’t appear to actually work as well as caffeine interestingly the blood concentration of caffeine appears to rise more slowly and are overall lower in when caffeine is obtained from energy drinks
Than compared to when drinking warm coffee and the last way that people are administering caffeine is through the nose uh via like an intranasal spray 20 seconds unfortunately it doesn’t actually increase blood levels of caffeine and doesn’t appear to actually improve performance when tested so there are many different ways to administer caffeine overall
Oral caffeine is rapidly and completely absorbed about 99 is absorbed within 45 minutes of ingestion provided it’s not taken via this swish and spit like oral rinse or nasal misting caffeine metabolism is actually increased meaning caffeine is broken down faster by individuals who smoke if they’re fasting or vigorous exercise whereas metabolisms actually slow
Down perhaps to a clinically insignificant degree by grapefruit an important note is that repeated administration of caffeine doesn’t really change its pharmacokinetics so it’s absorption and you know time to peak in the body what people commonly talk about with respect to caffeine is tolerance but tolerance is not observed for all effects of caffeine such as
The cognitive and physical performance improvements those seem to persist even though you’re getting some tolerance effect you mostly become tolerant to physiological changes like changes in heart rate and blood pressure that only occur in caffeine naive individuals but not necessarily in those who are habitual consumers that being said there are withdrawal
Symptoms sometimes seen following caffeine cessation symptoms include headache irritability nervousness and a reduction in energy and at this time the physiological basis for these symptoms are unknown although the development of withdrawal symptoms might indicate an addictive property caffeine does not actually have a convincing profile as an addictive drug
Dosing caffeine can get a little bit complicated but let’s start out with what the evidence says a number of recent systematic reviews and meta-analyses indicate that the ergogenic or performance-enhancing dose of caffeine falls somewhere in this three to nine milligrams per kilogram body weight range however the correct dose for an individual is going to differ
Based on the source of caffeine the specific exercise test and likely further vary between individuals based on their individual physiology preferences etc from our practical standpoint i like when individuals start on the lower end that three milligrams per kilogram and so if you have a 70 kilo or 154 pound individual um and coffee has a hundred milligrams
We’ll say of caffeine per cup uh two cups of coffee gives you 200 milligrams of caffeine and that’s right at that three milligram per kilo level they might need more than that to actually see a performance benefit but in any case that’s a good place to start on the low end and take about 60 minutes prior to exercise and that should give most folks an ergogenic
Or performance enhancing benefit individual preferences with respect to caffeine source sensitivity exercise etc should always be taken into consideration and the dose should be tailored appropriately so overall i like starting at the low end of the range three milligrams per kilo body weight and seeing how folks do if they see a performance improvement there
That’s great if they don’t see a performance improvement and they don’t have any you know untoward side effects based on their preferences and their individual physiology might increase that dose a little bit working up until we see an effect again with respect to tolerance the main thing that we see is a reduction or attenuation of uh sort of the physiological
Side effects like heart rate blood pressure increases and stuff like that we don’t really see this sort of reduction in cognitive or performance benefits which is good which means you don’t necessarily need a caffeine holiday unless you’re trying to sort of suss out some maybe sleep issue that you feel like you’re having from this or other sort of side effect
That you feel like is due to caffeine it’s probably not worth doing from a performance improvement standpoint meaning if you take a break from caffeine for a week you know you’re probably not going to come back and have improved results when you start using caffeine again in the gym you might feel a little bit more amped up but as far as the actual data on
Physical performance probably not saying all that i don’t know that every single workout is the most important workout of your life and you actually need a performance improving you know our performance enhancing sort of substance every single time my personal opinion is that the most important workouts that you do should probably you know you could reason to
Take caffeine before them that’s fine um and you know again not every workout is the most important workout of your life so for me days one and two i usually take caffeine beforehand and then on days three and four i typically don’t unless i’m tired and in which case i do um you know because that happens the main thing is i try to avoid taking caffeine within
That six to eight hour range before it’s time to go to bed based on the most recent systematic reviews and meta-analyses caffeine ingestion does appear to improve both cognitive and physical performance with respect to physical performance we’re talking about aerobic endurance muscular strength muscular endurance power jumping performance etc but how much
Does caffeine actually move the needle so for aerobic endurance uh when you pull all the studies together you see about an average of 16 percent increase until the time to exhaustion on tasks like run or cycle to exhaustion at 80 of the vo2 max with respect to muscular strength we tend to see a three percent increase in 1rm and vertical jump when you again
You pull all the studies testing this sort of stuff together when we look at how fast individuals can actually complete an aerobic task specifically in the 45 second to eight minute range we typically see that they’re about one to two percent faster with caffeine in general there’s a larger effect the shorter the event is even though there is data showing
Improvements in endurance in long long distance events but with respect to speed we’re talking about one to two percent improvements in that 45 second to eight minute range with potentially a bigger effect in the shorter distance also again improves things like power jumping and as we mentioned earlier cognitive functions such as vigilance so your alertness
Reaction time memory reasoning learning decision making and reduces errors in both folks who had a good night of sleep and who are sleep deprived overall the data is pretty robust supporting an improvement although one caveat most of the studies are performed in men only there are a handful of studies on women specifically with respect to physical performance
And shows an improvement there as well although when they use lower doses so one and 1.5 milligrams per kilo body weight it appears to only be in muscular strength not necessarily muscular endurance but again there are other studies which are all linked in the description below alright so that’s a wrap on caffeine in summary caffeine is super common about 85
Percent of individuals in the united states consume at least one caffeinated beverage per day it works via a bunch of different mechanisms ultimately with respect to physical performance probably just increasing the muscles excitability as far as dosing we’re looking at three to nine milligrams per kilogram body weight start on the lower end work up over time
As far as the type of caffeine would prefer a liquid beverage coffee is great should you prefer that but other other sources as well probably avoid the swish and spit and the intranasal administration with respect to health there does seem to be a net benefit with respect to caffeine intake particularly if it comes from coffee although individuals who are very
Sensitive to it or don’t tolerate well obviously should avoid it with respect to sleep would recommend avoiding caffeine intake about six to eight hours prior to sleep if you find you’re more sensitive to that you can even push that back further although again the relationship between sleep and caffeine intake is very very complicated and then finally caffeine
Does appear to have a pretty good size effect on a bunch of different physical and cognitive performance tasks so if you’re looking to improve your performance you’re looking for a little leg up caffeine pre-workout about 60 minutes or pre-test perhaps about 60 minutes may improve your performance so that’s it on caffeine thank you guys so much for watching
Make sure you subscribe to get updates on all the latest content make sure you hit the like button if you did indeed like the video and hey let us know what you think in the comments below uh pretty excited to hear from you guys and any additional topics you want us to cover right here on the barbell medicine youtube channel until next tuesday see you guys foreign
Transcribed from video
A Doctor Weighs In On Caffeine for Health And Performance By Barbell Medicine
