All About Caffeine

By Nichelle Haynes, DO

Are you someone who gets up in the morning and looks forward to your cup of coffee or tea? I am. I love to have a cup of coffee in the mornings before getting the day going. It is now part of my routine every morning and something I look forward to. If you enjoy a cup of coffee, tea, soda or energy drinks you’re in the majority. About 85% of Americans consume caffeine. Most of the time this caffeine comes from coffee in adults and soda in teenagers. It is no surprise caffeine is the most widely consumed psychoactive drug.

It is common knowledge caffeine can help you stay awake or more alert, just ask any student cramming for an exam, night shift worker or new parent! You know caffeine helps keep you awake, but do you know how? To keep it fairly simple, adenosine is a chemical which is present in all your cells. It has a variety of jobs, but one of its jobs is to help you know when you’re sleepy. Caffeine works in a complicated way but basically prevents adenosine from doing its job of making you sleepy. Caffeine can also stimulate parts of your nervous system and has been shown to improve motor coordination, concentration and wakefulness. Caffeine can also stimulate other parts of your body including your GI tract, which is why you may have a bowel movement after a cup of coffee.

Caffeine has been shown to worsen insomnia. This is especially true if you’re drinking caffeine less than 9 hours prior to bedtime. This means if you’d like to go to bed around 10 PM your last caffeinated drink should be with lunch or before. About 9 hours after consuming caffeine about ¾ of the caffeine is gone from your system. Depending on how much caffeine you consumed, this could mean a significant amount of caffeine is still in your system impacting your body’s sleep/wake cues to prevent you from being able to fall asleep.

Even moderate amounts of caffeine have been shown to worsen anxiety. This may be due to caffeine acting as a stimulant. It can stimulate your heart, breathing, and make you feel jittery. These are similar to anxiety and it is difficult for your body and brain to differentiate the two. When your body is feeling stimulated it may imitate a “fight or flight” response and cause your brain to search for why your body is feeling this way. If you’re experiencing anxiety, it may be helpful to monitor your caffeine intake and see if you have worsened anxiety on days where you’re consuming more caffeine.

In general, tea has less caffeine than coffee, with black tea having more caffeine than green tea. Tea ranges between 20 to 75 mg of caffeine per serving.  A serving of espresso has about 100 mg of caffeine and regular drip coffee can range from 115 mg to 175 mg. The amount of caffeine in a cup of coffee can vary based on the seed which is used and how it is prepared. Sodas have varying amounts of caffeine as well, usually somewhere between 30-70 mg. These numbers are important to monitor because there are different recommended “safe” amounts of caffeine for women who are pregnant, women who are breastfeeding and people of differing ages.

Most doctors recommend having less than 150 mg of caffeine during pregnancy and less than 300 mg while breastfeeding. Caffeine in low to moderate doses is considered “safe” in pregnancy but at high doses there is some evidence of increased risk of miscarriage. Caffeine can be found in breast milk with peak concentrations about 2 hours after mothers consumption. Babies, especially newborns, are not as good at metabolizing caffeine. This means it can last in their system a lot longer than it would a breastfeeding moms. In general, this is relatively safe because the amount excreted in breastmilk is very low. When a mom is consuming over 750 mg of caffeine a day (thats over 5 cups of coffee!), one study showed the baby can show signs of being stimulated by the caffeine. This may include being extra irritable, fussy or not sleeping as well.

When you consume caffeine for a period of time then stop you can have withdrawal symptoms like sleepiness, irritability or headache. This is especially true when caffeine is stopped “cold turkey.” To reduce the effects of withdrawal you can usually cut back your caffeine amount slowly.

That’s probably way more than you ever wanted to know about caffeine! It is so widely used but is not always discussed. Talk to your doctor if you’re having caffeine. They can provide you with information specific to you.

-Dr. Haynes

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