Using Caffeine to Optimize Mental & Physical Performance - Huberman Lab  ## Metadata - Author: **Huberman Lab** - Full Title: Using Caffeine to Optimize Mental & Physical Performance - Category: #podcasts - URL: https://share.snipd.com/episode/3ac72544-ad9f-4012-821c-4b611233b231 ## Highlights - Caffeine's Effect on Reaction Time Key takeaways: • Caffeine reduces reaction time. • It doesn't make it longer, it makes it shorter. Transcript: Speaker 1 But a little bit later, I'll talk about how you can consume caffeine at regular intervals while doing mental work or physical work in a way that can further increase mental performance And physical performance. But let's just touch on what caffeine intake really does for mental performance and physical performance. Perhaps the most robust finding across all of the studies that I've examined is that caffeine reduces our reaction time. That is, it improves our reaction time. It doesn't make it longer. It makes it shorter. So, for instance, in a laboratory study where people were asked to hit a lever every time they hear a tone, you can greatly reduce the time between the tone and the pressing of the lever If people ingest caffeine about 30 minutes before they do that task. Now, that seems like a trivial task, but this is also seen in the domain of sports performance and even in cognitive performance where people have to arrive at a particular answer to A question. And the answer to that question has to be pulled from their memory banks within their brain, their hippocampus, for instance, a brain structure involved in memory. And if you are asking people, for instance, to remember the capitals of different states or cities or to remember certain historical facts, they will do that at a particular rate. But if they've ingested caffeine within the hour prior, their ability to recall that information is much, much better. They are faster and it does not appear that accuracy is reduced. ([Time 0:18:16](https://share.snipd.com/snip/d2df4c94-cadd-4a99-96db-6b839cbad5ab)) - The Effects of Caffeine on Sleep Key takeaways: (* Adenosine accumulates throughout the day, and can bias you towards feeling more sleepy than you would otherwise., * Caffeine allows us to divorce ourselves from the circadian cycle.) Transcript: Speaker 1 We'll talk about why that is because it turns out there's a way to completely clear adenosine out of your system in the hour or so after waking. But for most people, adenosine levels are going to be close to their lowest after a good night's sleep. But there's really no negotiating the accumulation of adenosine that's going to occur and going to bias you towards feeling more sleepy than you would otherwise that's going to occur throughout the day. There's really no way to eliminate adenosine. All you can really do is block its function. So it's sort of like borrowing energy against the fatigue that you will inevitably feel. Now, this actually has very important socio-economical relevance. Before caffeine was regularly consumed by human beings, we were really slaves to the light dark cycle. And this was especially true before the presence of artificial lighting. But even before the advent of artificial lighting, humans were largely constrained to the outside light dark cycle. We need to be active during the day and working during the day and we need to be asleep at night. Caffeine allows us to divorce ourselves from that circadian cycle. Circadian just means about 24-hour. Caffeine allows us to do that at least somewhat by way of increasing our alertness, that is spiking our alertness at various times throughout the day and even at night. This is how we can have shift workers for instance that can sleep during the day and then drink a strong cup of coffee at 8 p.m. ([Time 0:41:23](https://share.snipd.com/snip/50e4c45c-4746-4dd8-98ae-7fdbb9f431df)) - How Much Caffeine Is Safe to Ingest? Key takeaways: (* People should start thinking about the dosage of caffeine they are ingesting and the timing in which they ingest it., * People who are considering using caffeine should start with the lower end of the dosage range.) Transcript: Speaker 1 That means that one to three milligrams, again, milligrams, thousands of a gram, one to three milligrams of caffeine per kilogram of body weight would mean for me. I could safely ingest 100 to 300 milligrams of caffeine in a single dose in a single drink. If that's the way I'm consuming it or pill form if that's the way that I'm consuming it. And it's very likely that that would be a tolerable dose. However, if you are not somebody that's accustomed to drinking caffeine on a regular basis, I suggest you start on the lower end of that one to three milligrams per kilogram of body weight range. So for instance, if you're somebody who weighs 50 kilograms, that's approximately 110 pounds and you would be pretty comfortable ingesting somewhere between 50 and 150 milligrams of caffeine. So what I recommend is that people who are considering using caffeine as a tool or who are already ingesting caffeine start to think about the dosage of caffeine that you are ingesting or plan to ingest and the timing in which you ingest that caffeine relative to certain tasks throughout your day. You're waking and you're sleeping. We'll talk about that in just a moment. But the first step for you is to figure out how much you weigh in kilograms and then to go to that number of one to three milligrams of caffeine per kilogram of body weight. And that's a good range in which you might want to explore the use of caffeine in a single application, meaning in a single dose. ([Time 0:46:32](https://share.snipd.com/snip/091cf621-5c98-44ff-bb69-98a0bbe29b76)) - How to Determine if You're Caffeine Adapted Key takeaways: (* If you're ingesting 200 milligrams of caffeine and that's the appropriate dose for you based on your body weight and then you are ingesting another 200 milligrams of caffeine an hour later, you are effectively ingesting approximately 400 milligrams of caffeine, which is going to start exceeding the dose in which you can normally tolerate without feeling anxious and jittery., * There is a range of tolerance for caffeine that's based on two things. One is a preexisting disposition that is whether or not your genetics and nervous system in the backdrop of your life, how much stress you're experiencing tends to make you feel more anxious and alert and jittery before you ingest any caffeine. And the other is how so-called caffeine adapted you are.) Transcript: Speaker 1 Just keep in mind that if you're ingesting 200 milligrams of caffeine and that's the appropriate dose for you based on your body weight and then you are ingesting another 200 milligrams of caffeine an hour later, you are effectively ingesting approximately 400 milligrams of caffeine, which is going to start exceeding the dose in which you can normally tolerate without feeling anxious and jittery. With all of that said, there is a range of tolerance for caffeine that's based on two things. One is a pre-existing disposition that is whether or not your genetics and nervous system in the backdrop of your life, how much stress you're experiencing tends to make you feel more anxious and alert and jittery before you ingest any caffeine. And the other is how so-called caffeine adapted you are. We often hear about tolerance. Tolerance means something very specific. It's the ability to ingest more and more of something with a plateau that is a non-in no increase or an actual reduction in the effectiveness of that thing. But here we're not really talking about tolerance to caffeine. What we're talking about is being caffeine adapted. A simple way to understand whether or not you're caffeine adapted or not is that if you drink caffeine and it tends to increase your heart rate and make you feel more alert and a bit more anxious, then chances are you are not caffeine adapted. Provided the amount of caffeine is within the healthy range for you. That is the range as we talked about a moment ago. However, here's somebody who drinks caffeine and you actually feel alert and relaxed. Chances are you are caffeine adapted. ([Time 0:49:13](https://share.snipd.com/snip/23236283-617c-4345-88c4-3650a5bc8902))