Have you ever had a cup of coffee, or maybe even a double-shot latte, and suddenly felt like you were going to fall asleep? It's the worst. You're sitting at your desk, trying to get stuff done, but suddenly, you feel like you need a nap. You start thinking: "Why does caffeine make me tired?." There are some reasons why these symptoms may be occurring.
First, caffeine is known to block the effects of adenosine (a chemical In the brain) which controls our sleep cycle7Z. L. Huang, Y. Urade, O. Hayaishi. (2011). The role of adenosine in the regulation of sleep. Curr Top Med Chem. DOI:10.2174/156802611795347654; second, it acts as a diuretic so that you lose more water through urination than normal which in turn leads to tiredness and lastly, it could be due to the sweetener you added to your coffee. Either way, let's look at the science behind this phenomenon and find out why caffeine makes you tired and jittery.
Caffeine is a stimulant, and it might seem like it would make you more awake, but when your body processes caffeine, it releases adrenaline (the fight-or-flight hormone)4Rajeev Dalal, Dejan Grujic. (2022, May). Epinephrine. NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK482160/ and other hormones like cortisol that can cause feelings of anxiety or stress5Lauren Thau, Jayashree Gandhi, Sandeep Sharma. (2022, Aug). Physiology, cortisol. NCBI. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK538239/. These hormones are what make your heart race and make you feel alert and awake. But when they're released too often or in large amounts, they can start to have the opposite effect by causing fatigue and drowsiness.
Caffeine also blocks your body's adenosine receptors. Adenosine is a central nervous system chemical that controls our sleep cycle. As adenosine levels rise during the day, we feel more awake and energetic; as those levels drop at night, we become sleepy and tired1T. Porkka-Heiskanen. (1999). Adenosine in sleep and wakefulness. Ann Med. DOI:10.3109/07853899908998788. By blocking adenosine receptors (making them non-responsive), caffeine tricks your body into thinking it has more energy than it does by blocking signals from other parts of your brain telling you to slow down and rest.
Without these inhibitions, your brain is more stimulated and produces more dopamine (the "feel-good" hormone)3Stephanie Watson. (2021, July). Dopamine: The pathway to pleasure. Health Havard. Retrieved from https://www.health.harvard.edu/mind-and-mood/dopamine-the-pathway-to-pleasure. This can be helpful if you need an extra jolt of energy or want to feel alert for a short period, but if you consume too much caffeine over time, it can cause you to feel anxious or jittery.
This is because your body starts to build up a caffeine tolerance2Havard. (n.d). Cafffeine. The Nutrition Source. Retrieved from https://www.hsph.harvard.edu/nutritionsource/caffeine/. Tolerance is the body's natural process of getting used to the effects of a stimulant like caffeine. When this happens, your body will have less access to adenosine receptors and, therefore, won't need as many for normal functioning. This means that when you try to sleep later on in the day after consuming caffeine earlier in the day, there won't be enough adenosine receptors left to inhibit brain activity, so when the lights go out at night, your brain will keep firing away.
However, it is important to remember that every person is different regarding how their body reacts to caffeine. Some people will experience more energy from caffeine than others; others will feel no difference. It all depends on how your body processes the drug and what kind of receptors it has in place for receiving it.
Yes, caffeine can make you sleepy all the time. Caffeine is a stimulant that helps your body stay awake by increasing your body's adrenaline and stimulating the central nervous system. Adrenaline gives you the energy to run from a bear or stay up all night writing a paper, but it also makes your body release more adenosine, a chemical that tells your brain to sleep. The effect of caffeine on adenosine is temporary, so if you drink coffee in the morning, you'll be less likely to sleep at night. But when you stop drinking coffee, your body will start producing more adenosine again, making you feel tired and sleepy during the day.
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Coffee is a great way to start your day and keep going throughout the rest of it. But you'll likely get tired and cranky if you drink too much. Here are some tips for how to minimize the causes of getting tired after drinking coffee:
While regular coffee does contain caffeine, decaffeinated coffee has less caffeine6FDA. (2018, Dec). Spilling the Beans: How Much Caffeine is Too Much? FDA. Retrieved from https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much#:~:text=For%20healthy%20adults%2C%20the%20FDA,associated%20with%20dangerous%2C%20negative%20effects.. Decaf is still made from coffee beans, so it'll still have all the flavor and health benefits of regular coffee but with fewer stimulant effects. This means that you can drink it without feeling jittery or overstimulated.
This is another good way to help your body adjust its internal clock so that it doesn't expect more stimulation as time goes by. If you're just not a fan of the taste of decaf, then try cutting down on your regular cup of joe by half or more you'll still get plenty of energy-boosting benefits without all the extra caffeine. A healthy adult can safely consume 400 milligrams, about 5 cups of coffee daily6FDA. (2018, Dec). Spilling the Beans: How Much Caffeine is Too Much? FDA. Retrieved from https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much#:~:text=For%20healthy%20adults%2C%20the%20FDA,associated%20with%20dangerous%2C%20negative%20effects..
If you find yourself gulping down cup after cup at once because they're so delicious, then consider spacing them out with some water instead this will help keep your body hydrated while allowing time for the caffeine to kick in before you have another sip.
While we love our sweet treats as much as anyone else, too much sugar can make us tired after eating or drinking. To keep your energy levels up while still enjoying your tasty brew, try using less or no sugar instead of sweeteners like honey or maple syrup. You'll still get all the flavor you love with fewer calories and less chance that those extra sugars will leave you feeling fatigued later on.
Coffee is a staple in many people's lives, and it's easy to get into drinking it every day. But if you're feeling tired after a cup or two, it's time to look at what else is happening in your life. If you're tired after your morning cup of joe, try cutting back on the caffeine or switching to decaf to see if that helps. Remember, not all caffeine comes in the form of coffee. Soft drinks, some medications, and energy boosters also contain caffeine, and the overall effect on your body depends on how much you take per day from all sources.
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