Can Caffeine Make You Tired?

Quick Health Scoop

• Roughly 80% of U.S. adults consume caffeine every day.
• Caffeine itself affects everyone differently, and although it’s a stimulant, it may make some people feel tired.
• A variety of factors can contribute to caffeine making you tired, including adenosine levels, caffeine tolerance, dehydration, and sleep deprivation.
• To avoid feeling tired, natural ways to boost energy including getting enough sleep on a regular basis, exercising, drinking caffeine in moderation, and choosing alternative, caffeine-free drinks.

If you rely on a cup of coffee, energy drink, or soft drink to give you a caffeine boost for some much-needed energy, you’re not alone. According to the U.S. Food and Drug Administration, approximately 80% of U.S. adults consume caffeine in some form every day. [1]

As a stimulant, caffeine does help keep you alert and give you a jolt of energy, at least temporarily. But for some people, caffeine has the opposite effect. Can caffeine make you tired? And are you one of those people who experiences a caffeine crash instead of an energy burst?

Let’s find out what’s going on.

Signs That Caffeine Makes You Tired

If you notice that your energy level tanks after drinking coffee (or other caffeinated drinks), that might be a sign that your body has built up a caffeine tolerance. Telling signs of caffeine making you tired include a feeling of daytime sleepiness and decreased alertness.

Why Does Caffeine Make You Tired?

Just like alcohol and medications can affect people differently, caffeine works in a similar way—it affects people differently. For some people, one cup of coffee can make them tired, while others can drink three cups of coffee and feel fine. Why? Because everyone’s body processes caffeine differently. [2]

It’s not just one factor that makes you tired. Several things are at play that can contribute to your fatigue, including adenosine levels, caffeine tolerance, dehydration, suffering from lack of sleep, or differences in in how your body metabolizes caffeine. [3]

Sugar crash

If you’re not one to drink your coffee black, you probably add milk or sugar or both. If you order lattés and other specialty coffees, you might also get your drink topped off with a splash of flavored syrup or whipped cream. All this adds up to an increased amount of sugar in your caffeinated beverage—leading to a sugar crash soon after. Ditto for energy drinks and soft drinks, both of which contain a lot of added sugar. After the initial sugar high, an energy slump might follow, leading to a feel of sleepiness.

Tolerance

People who enjoy a regular caffeine intake commonly develop a caffeine tolerance. This can lower caffeine’s stimulant effects unless a larger quantity is consumed. Many Americans drink an average of 135 mg of caffeine a day, which is equal to about 1.5 cups of coffee. According to the U.S. Food and Drug Administration, most healthy adults can safely consume up to 400 milligrams (about four cups brewed coffee) every day. [4]

Stress

Caffeine consumption can increase the body’s cortisol levels (a.k.a. the stress hormone). Higher cortisol levels can make you feel more awake (at least initially) and have a heightened sense of alertness. This can make you feel stressed, fatigued, and also affect your sleep.

Dehydration

Did you know that caffeine is a diuretic? In laymen’s terms, this just means it makes you urinate more frequently. And the more you pee, the more your body loses water, which can  lead to dehydration, which can then make you feel tired.

Adenosine

Your body produces a hormone called adenosine, which is responsible for deep sleep. [4] When you’re tired at the end of the day, that’s partially the result of adenosine building up throughout the day. [2] How does caffeine come into play here? It can thwart the effects of adenosine by binding to the brain’s adenosine receptors. Not only does this decrease adenosine levels, but it also affects the levels of other sleep-related hormones such as dopamine, GABA, norepinephrine, and serotonin. [4]

And remember that caffeine tolerance mentioned earlier? Adenosine is involved. As you  regularly consume caffeine, your body adapts by making more adenosine—so you need more caffeine to get that same wide-awake feeling. [2]

Adenosine is also responsible for the unpleasant feeling of suddenly quitting caffeine. If you stop consuming caffeine, all that extra adenosine can cause withdrawal symptoms, including headaches, irritability, increased sleepiness, and agitation. [2,4]

Avoid Tiredness

Can caffeine make you tired? Yes, sometimes. To avoid feeling fatigued, follow a few natural ways to boost energy.

Sleep

This might sound like a no-brainer, but lack of sleep can make you feel tired. Therefore, the best way to feel refreshed and full of energy is to get consistent, adequate sleep every night. While age and lifestyle play a role in the amount of sleep you need, experts generally recommend that most adults need 7-9 hours of sleep every night. [5]

Moderation

Since the F.D.A. says that most healthy adults can safely consume 400 milligrams (about four cups brewed coffee) every day, limit your caffeine intake based on those recommendations.

Due to the caffeine withdrawal mentioned earlier, you might want to slowly taper your caffeine intake instead of going cold turkey to help minimize withdrawal symptoms. Caffeine withdrawal hits hardest within the first few days of quitting caffeine but typically lessens after a week. [4]

Alternative drinks

If you like a hot beverage in the morning, consider switching to green tea, decaffeinated herbal tea, decaf coffee, or even “golden milk” (a blend of warm milk and good-for-you spices such as turmeric, ginger, and cinnamon). This way, you can still enjoy your morning routine without the caffeine.

Throughout the day, quench your thirst with water, milk, 100% fruit or vegetable  juice, and other caffeine-free beverages that are low in sugar.

Exercise

Did you know that exercise can help boost your energy and help improve your sleep quality? Engaging in exercise delivers oxygen and vital nutrients throughout your body, helps promote proper functioning of your cardiovascular system, enhances muscle strength, and improves endurance. [6] Hours later, exercise helps you fall asleep quicker and enjoy better quality sleep.

Bottom Line

Can caffeine make you tired? Caffeine affects everyone differently. While caffeine is a stimulant, coffee consumption can sometimes have the opposite effect. So, yes, caffeine can make you tired. Because they may have built up a caffeine tolerance, some people feel tired instead of energized after drinking a caffeinated beverage. A variety of factors can contribute to feeling tired after caffeine consumption including adenosine levels, caffeine tolerance, dehydration, and lack of sleep. To avoid feeling fatigued, make a few healthy lifestyle changes to boost energy, such as getting adequate sleep on a regular basis, exercising, drinking caffeine in moderation, and choosing alternative, caffeine-free drinks.

Continue to check back on the Nature Made Blog for the latest science-backed articles to help you take ownership of your health.

This information is for educational purposes only and is not intended to serve as medical advice or a recommendation for any specific product. Consult your health care provider for more information. 

References 

1. The National Institute for Occupational Safety and Health. “Caffeine & Long Work Hours.” April 1, 2020. Accessed on: August 18, 2022. https://www.cdc.gov/niosh/emres/longhourstraining/caffeine.html
2. NIH News in Health. “Tired or Wired? Caffeine and Your Brain.” October 2020. Accessed on: August 18, 2022. https://newsinhealth.nih.gov/2020/10/tired-or-wired
3. Sleep Foundation. “Why Does Coffee Make You Tired?” 2022. Accessed on: August 20, 2022. https://www.sleepfoundation.org/sleep-faqs/why-does-coffee-make-me-tired
4. Harvard T.H. Chan School of Public Health. “Caffeine.” 2022. Accessed on: August 18, 2022. https://www.hsph.harvard.edu/nutritionsource/caffeine/
5. National Sleep Foundation. “How Much Sleep Do You Really Need?” October 1, 2020. Accessed on: August 20, 2022. https://www.thensf.org/how-many-hours-of-sleep-do-you-really-need/
6. Mayo Clinic. “Exercise: 7 benefits of regular physical activity.” October 8, 2021. Accessed on: August 20, 2022. https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise/art-20048389