Whether you are a coffee-shop junkie or a cold-brew enthusiast, if you’re among the 59% of Americans who drink coffee, that java buzz after downing a cup is probably familiar to you.
But are you aware of the extent to which this beverage can affect nearly your entire body within minutes post-sip? Join us as we take a look at how a cup of coffee affects your system right after you drink it —some of its effects are pretty astounding.
If you need to pull an all-nighter, push through a tight deadline, or stay alert for a long drive, a mug of coffee can be your BFF. “Caffeine is a stimulant, and some evidence shows that it can increase mental functioning and strengthen your ability to concentrate,” according to Marc Leavey, MD, a primary care specialist at Mercy Medical Center in Baltimore.
The brain sends out chemicals called neurotransmitters through synapses — that’s how we are able to think. Caffeine is a psychoactive compound that allows these neurotransmitters to operate more efficiently. “As a result, the brain is able to better process chemical messengers,” Leavey explains. “When used in moderation, coffee gives you an edge.” You start to feel more mentally alert after some 30 minutes, and the effects lasts a few hours.
The key word, of course, being moderation. Overconsumption of caffeine can overwhelm your system and sabotage your concentration, leaving you anxious and jittery.
Caffeine also activates your sympathetic nervous system, activating fight-or-flight mode. “It stimulates the receptors in your brain that tell your body to rev up and produce more adrenaline,” explains Nieca Goldberg, MD, cardiologist at NYU Langone Medical Center. What this means for your eyes? – Sharper vision.
“Research suggests that if you drink coffee, your pupils may dilate very slightly,” Leavey says. “It’s so subtle that you wouldn’t be able to notice it just by looking in the mirror, but you may feel that you can see better.”
Too much coffee can give your pearly whites a corn-kernel effect, but there’s one more side to the story. “Coffee contains a fair amount of polyphenols, micronutrients that have been shown to be effective in killing oral plaque and bacteria,” says NYC-based dentist Keith Arbeitman. However, as soon as you add milk, sugar, or syrup, those very same benefits backfire.
“It’s a double-edged sword, because once the polyphenols dissolve the layer of plaque, milk and sugar can easily access areas deep within the teeth,” Arbeitman explains. “This leads to demineralization and eventual decay.” Essentially, as long as you stick to black, you’ll be doing your teeth a favor. Otherwise, you’re making them even more vulnerable to cavities than usual.
If you can’t imagine your morning coffee without milk and sugar, try drinking from a straw to limit the amount of time the sugars have to hang around in your mouth. Then brush your teeth afterward to correct your oral pH and neutralize residual sugars.
If you heart coffee, you should know that coffee hearts you too – the most immediate physical effects of a coffee fix are indeed cardiovascular. “Caffeine increases the sensitivity of your neural pathways so that the electrical impulses responsible for triggering your cardiovascular system pass through the body more easily,” Leavey says. “Consequently, about 15 minutes after drinking a cup, the caffeine begins to elevate your pulse and blood pressure by an average of 10 to 15 percent.”
Consuming two six-ounce cups a day isn’t dangerous for most people, but a greater intake can be challenging if you have underlying issues like heart disease, high blood pressure, or tachycardia. “It may increase cardiovascular activity to the extent that it can cause a heart attack,” continues Leavey.
There might be some rationale behind downing an espresso after dinner. “Caffeine triggers the receptors in your stomach, boosting gastric secretions by about 10 to 15 percent — a small, but meaningful, increase,” says Leavey. These higher levels of acid help you digest your meal faster.
The flip side, however, is potential cramping, acid reflux, or heartburn. “Caffeine relaxes the sphincter, which is a bundle of muscles located at the base of your esophagus that acts as a gate to keep food from entering your trachea,” says Goldberg. “As a result, stomach contents can travel backward into the esophagus.”
Hand-in-hand with a quick-acting stomach is a quick-acting bowel activity … which means you may be struck by a tush-quake.
“Caffeine stimulates your bowels, telling them to work harder and faster,” Leavey explains. “But fecal matter has to remain in the bowels for a certain length of time in order to become a solid. If it moves too quickly, it will emerge still in liquid form.” Irritable Bowel Syndrome (IBS) sufferers are particularly at risk.
Every devoted coffee drinker knows the dangers of gulping your way through a Grande when you’re stuck in traffic or miles away from a bathroom. “Coffee acts as a diuretic, influencing the tubules in your kidneys to send more water through,” Leavey says. “That, in turn, leads to increased urinary output.”
The diuretic effects exist whether you’re drinking regular or decaf, so it’s not the caffeine at play. “Coffee contains other stimulating compounds, including steroid-like molecules that physiologically provoke the bowels and bladder,” Leavey adds.
Most people don’t think of coffee as problematic in terms of cholesterol. However, most studies suggest otherwise. “Coffee beans contain oils that are shown to increase cholesterol,” Leavey says. “These oils are sifted out if you drink filtered coffee, but not in a French press.” The next time you order an unfiltered brew, look at the surface of your cup carefully — you’ll see globules of fat floating on top.