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Coffee & Health

Where in the Body Does Caffeine Act?

For many individuals, starting the day with a hot cup of joe has become an important part of their morning routine. Not only does it taste delightful, but that dose of caffeine can help you get the jump on your day. It’s no wonder then that according to the U.S Food and Drug Administration (FDA), more than 80% percent of adults in America consume some form of this stimulant daily – making it one of the world’s most popular drugs!

caffeine in body

Whether it’s from coffee beans, tea leaves, chocolate bars or other sources; there are multiple ways we receive our hit and each will have its own unique impact on our bodies. So where in the body does caffeine act?


Caffeine Activity in the Body

As a coffee lover, you probably know a thing or two about the effects of caffeine on your body. In order to make sense of it all, let’s break down how adenosine receptors work and why they are so important. Adenosine is an essential purine nucleotide base that plays a major role in ATP – an energy molecule’ found throughout the body.

It helps regulate various processes from neurotransmitter release to vasodilation/vasoconstriction and T cell proliferation – one of its main functions being inducing sleepiness in the brain!

Caffeine enters our system and binds itself to these same adenosine receptors, blocking them from connecting with actual adenosine molecules – causing quite a stir up! This disruption leads not only to more alertness but also affects hormones like norepinephrine, dopamine and GABA; which ultimately affect moods too!

Have you ever felt a deep exhaustion hit you just a couple hours after guzzling down your morning cup of joe? That’s what we call the caffeine crash. It happens when all that built up adenosine floods back into our receptors. Consequently, it makes you feel to retire to bed.

Additionally, caffeine effects calcium movement between body cells. Essentially, neurotransmitters rely on calcium on their nerve endings. In case there’s excessive caffeine in the body, the endoplasmic reticulum will be inhibited to absorb and release calcium.

Regrettably, caffeine consumption in toxic amounts may prevent the cyclic adenosine monophosphate (cAMP) from breaking down. Basically, cAMP triggers the release of certain hormones such as dopamine into the blood. Collectively, these issues can cause a serious and life-threatening effect.


Caffeine Activity in the Brain

It feels quite relaxing to take a cup of joe after a tiresome day, thanks to its effect in boosting mood. Besides, research findings indicate that caffeine enhances alertness and focus for up to three hours, giving you that extra push when you need it most. However, heavy consumption of caffeine comes with its own set of side effects—including tension and anxiety—so moderation is key here.


Caffeine in the Heart

If your morning ritual includes a caffeine kick-start, it’s worth knowing what this stimulant does to your body. Caffeine is a vasoconstrictor; it narrows blood vessels which leads to an increase in both blood pressure and heart rate – but only temporarily.

If you’re someone who drinks coffee regularly, however, these effects might be lessened due to tolerance building up over time. High blood pressure sufferers needn’t worry though; research suggests that moderate amounts (4-5 cups per day) won’t cause any long term issues with BP levels.

What about our hearts? Well scientists are divided on whether or not caffeine can lead directly to cardiovascular disease – some studies report positive outcomes from drinking coffee while others suggest more evidence is needed before we arrive at any conclusions! All in all though, as long as you stick within reasonable limits then there’s no need for concern!


Reproductive System and Caffeine

Caffeine has the power to move throughout your body, even reaching the placenta. As a stimulant, it can cause your baby’s heart rate and metabolism to increase faster than usual. Too much of this drug can lead to slower fetal growth and an elevated risk of miscarriage. However, in most cases moderate amounts are safe during pregnancy.

According to experts at Mayo Clinic, if attempting conception, you should try not exceed 200-300 milligrams of caffeine per day; large dosages could interfere with estrogen production needed for successful fertilization.


Excretory and Digestive Systems

Caffeine can be a real buzzkill – literally. Not only does it increase the amount of acid in your stomach, which may lead to heartburn and upset stomach, but you also don’t get to store it up for later use either. It’s processed by the liver and then exits out through urine – hence why many people find themselves having an increased urge to pee shortly after drinking something with caffeine in it.

If you have any history of digestive issues like acid reflux or ulcers, make sure that you check-in with your doc before going overboard on caffeine consumption!


Effect on Muscular Skeletal Systems

It’s important to watch out for the amount of caffeine you consume — too much can interfere with calcium absorption and metabolism, leading to bone thinning (osteoporosis). Not just that, but excess consumption may also cause muscle twitching. On top of all this if you find yourself going through withdrawal symptoms then achy muscles may be one of them!


Sleep and Caffeine

People love the way caffeine helps them stay alert and energized, but overindulging can lead to serious consequences like sleep deprivation or insomnia. Studies have shown that in some cases, consuming caffeine may just be a means of restoring performance lost due to drowsiness – not actually increasing overall productivity.



It is important to remember that caffeine comes with some side effects. To make sure you don’t feel any adverse reactions while still getting your energy boost, try not exceeding more than 400 mg per day – which would be equivalent to four small cups of regular brewed java. So go on and fuel up with a Starbucks order without going overboard!