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How Much Caffeine to Drink to Stay Awake & Alert: Facts & FAQ

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Caffeine affects every individual differently. How caffeine affects you depends on how much caffeine you consume, the rest of your diet, your genes, and more!

So, how do you figure out how much caffeine to drink to stay alert? Read on to find out what you need to know about caffeine and staying wide awake! Although it depends on your caffeine tolerance and how much you usually drink, drinking two to four cups of coffee in a day can help you stay alert.

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How Does Caffeine Work?

When you drink or eat caffeinated substances, you are absorbing the caffeine molecule. Once it is in your system, caffeine travels throughout your body, even to your brain.

As it travels through your body, caffeine works to make you feel alert by blocking sleep-inducing factors in your body. One such factor includes adenosine receptors.

Adenosine receptors trigger tiredness, and tell your body when it is time to slow down. Caffeine works against adenosine receptors by attaching to those receptors and, rather than activating them, blocking the job they are meant to do.

This helps you stay alert and active, even when your adenosine receptors want to turn off the lights and take a nap.

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Image Credit: chiosphotographer, Shutterstock

How Much Caffeine Does It Take?

According to WebMD, up to 400 milligrams of caffeine a day is safe for the average adult. The average cup of black coffee contains 95 milligrams of caffeine. That means that up to four cups of coffee a day is safe for most adults.

Of course, everyone is different. Each person has a different tolerance for caffeine. If you drink lots of coffee daily, you may build up a tolerance for caffeine. If you rarely drink coffee, you may have a very low tolerance, and get jittery quite easily.

Depending on your weight, diet, lifestyle, and even your genes, your tolerance to caffeine and coffee will fluctuate. Always consult a doctor or medical professional when it comes to how much caffeine you should consume.

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Frequently Asked Questions

You’ve got questions, we’ve got answers. Check out some of the most frequently asked questions when it comes to how much caffeine it takes to stay alert.

How much caffeine can you consume in a day?

Generally, it is safe to consume up to 400 milligrams of caffeine in a day for the average adult. However, this is dependent on your lifestyle, body type, caffeine consumption, existing health conditions, and more. Always check in with your doctor, or other health care professional, when making decisions about your health and caffeine consumption!

woman enjoying cappuccino in a cafe
Image Credit: polinaloves, Shutterstock

How much caffeine will help you stay alert?

This depends on your body, tolerance, and various other factors. If you rarely consume coffee, even one cup can do the trick. If you consume large quantities of caffeine, upwards of four cups of coffee may be necessary to get you going.

What are the side effects of too much caffeine?

Too much coffee or caffeine can result in headaches, jitters, anxiety, high blood pressure, and more. Always be cautious with your caffeine consumption, and consult a medical professional before consuming more caffeine than you usually do.

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For many of us, caffeine is key to keeping our world spinning. Whether you’re staying up late for a friend’s birthday, or working through the night to meet a deadline, caffeine can help you get there. Of course, be cautious with your caffeine consumption, and be aware of how caffeine affects you personally.

Featured Image Credit By: Galina Zhigalova, Shutterstock


Sophie Short

Sophie Short is a freelance writer and coffee expert fully steeped in the specialty coffee community. She formerly worked at a specialty roaster and is now a coffee writer and consultant. She also serves as the San Diego Coffee Network President, where she develops coffee-related non-profit projects. Sophie enjoys travelling, community organizing, and (of course) drinking delicious coffee!

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