Coffee is a fast-acting stimulant that’s known to enhance performance and alertness, which is part of why it’s so popular around the world. But how quickly does the caffeine in coffee actually take effect?
The rate at which your body metabolizes coffee depends on several factors including your age, any alcohol consumption, how much has been consumed, and any medications you’re taking. A feeling of alertness usually starts to kick in within 15 minutes, and it can last for 2-3 hours.
Even though the feeling of alertness may fade after a few hours, it generally takes about 6 to 10 hours for your body to rid itself of all the caffeine, provided you don’t consume any more. In some rare cases, caffeine can actually remain in the bloodstream for several days. Let’s take a closer look at how the body processes coffee and what you can expect from your next cup.
How Quickly Does Coffee Kick In?
Coffee doesn’t instantly make you feel alert, but because the body absorbs it very quickly, the effects generally start to kick in within 15 minutes of consumption.
The effects will generally peak about an hour after ingestion, and as that happens, the sleep receptors will be fully blocked, causing you to feel significantly more energized and awake.
Depending on your level of caffeine tolerance, the effects of a cup of coffee can last up to 6 hours before they start wearing off. The science behind it is that during peak levels, the caffeine in coffee is absorbed fully in your bloodstream, causing your body to produce more adrenaline and cortisol. They’re the chemicals behind the jittery effect you may be familiar with.
A common misconception surrounding drinking coffee is that the effects kick in faster when you consume it on an empty stomach. That may be true to some extent, but drinking coffee on an empty stomach is not recommended because it can do more harm than good.
On an empty stomach, coffee can potentially cause severe heartburn and inflict damage to the stomach lining.
Why Caffeine Affects Everyone Differently
Not everyone will experience the same stimulating effect of coffee. In general, how your body reacts to caffeine depends on your genetic makeup. For caffeine to be effective, it has to attach to adenosine receptors.
Some people’s receptors aren’t as “sticky,” so they will naturally be less susceptible to the effects. Additionally, differences in response to coffee can occur due to the following factors:
Caffeine Tolerance
With regular consumption over time, coffee loses its effectiveness. This causes the human body to develop a tolerance to caffeine and become less responsive to its effects.
People with high caffeine tolerance often feel little to no effect after consuming more than the recommended amount.
Blood Sugar Levels
According to experts, caffeine not only impairs insulin reaction but it also makes your body resistant to insulin. Because insulin won’t be performing optimally and regulating glucose levels as it should, your blood sugar levels may spike after a cup of coffee.
Health Conditions
Caffeine is known to raise the heart rate and destabilize blood pressure. These side effects are even more pronounced in people with pre-existing health conditions like Arrhythmias and Epilepsy.
The Caffeine Content of Different Roasts
The general idea is that the more potent a particular coffee is with caffeine, the faster your body’s going to experience the effects. That is mostly true, except the difference in reaction time is insignificant in most cases.
Most coffee enthusiasts prefer to use a micro-roaster (on Amazon) to conveniently roast their own coffee beans from the comfort of their homes. There’s only one practical point to consider if you’re going down that road — the degree of roast affects the caffeine level.
Three things change during the process of roasting coffee beans: the flavor, the caffeine content, and the color. While the beans are being roasted, the caffeine content is gradually burned away. As a result, darker roasts have a lower caffeine content than their lighter-roast counterparts. In fact, lighter roasts generally have about 60% more caffeine.
That’s not to be confused with flavor changes though, because roasting the beans does give them flavor. Despite containing less caffeine, darker roasts (on Amazon) are often more flavor-packed.
How Long Does Caffeine Stay in your System?
When you drink coffee, it’s absorbed in your system in a matter of minutes, and the effects kick in shortly after. The feeling of alertness may wear off within 2 to 3 hours, but there will still be traces of caffeine in your system. All in all, it will take anywhere between 6 hours and a couple of days for caffeine to completely leave your system.
Once caffeine enters your body, there isn’t much you can do to flush it out faster than normal. Water may help limit the effects but it will not clear the caffeine from your bloodstream. The only thing you can do is wait it out.
Sometimes caffeine will stay longer in your system if you’ve overdosed. Caffeine overdose is a serious situation that can quickly get out of hand. If you suspect you’ve taken more coffee than recommended, watch out for any symptoms like dizziness, fatigue, fever, and increased thirst.
These are all common symptoms of having too much caffeine. However, you should seek immediate medical treatment if you experience severe symptoms like hallucinations or trouble breathing.
Other Factors Impacting Caffeine Metabolism
How fast caffeine kicks in also depends on caffeine metabolism. Simply put, caffeine metabolism is the process where caffeine is broken down, absorbed into your bloodstream, and cleared from your system.
The following factors largely influence the rate at which your body metabolizes caffeine:
Age
Caffeine metabolism slows down significantly with age. Consequently, caffeine has a bigger impact on older adults. A study discovered that senior citizens between the ages of 60 and 75 metabolize coffee 33% slower than the average Joe. They’re also more likely to struggle with the adverse effects.
Alcohol
Alcohol inhibits caffeine metabolism. Consequently, ingesting caffeine while under the influence of alcohol will only intensify its aftermath. On the other hand, the notion that caffeine speeds alcohol metabolism is a misconception. Caffeine may improve overall alcohol-influenced performance, but it will not help you sober up.
How Much Coffee You Drank
There’s a reason why the FDA set the healthy daily caffeine consumption at 400 mg a day. Anything beyond that enhances the side-effects.
Medication
Caffeine can interact with several medications to either reduce or enhance their effectiveness. At the same time, many drugs impact caffeine reaction and sensitivity. You’ll find that most typical caffeine symptoms, like alertness, are significantly more intense after ingestion of certain medications.