Menu

What does caffeine do to your body

Caffeine is a naturally occurring drug and the world's most popular psychoactive substance. It functions as a stimulant that's largely removed from euphoria and other recreational stimulant effects.

What does caffeine do to your body

It's usually legal and is used in various forms, including tea, coffee, and soda. The effects of a drug will vary for each user, so the most I can do is provide a general overview of the effects. The positive effects include bronchodilation, improved mental and physical performance, stimulation, reduced boredom, and mood elevation. Among the possible negative effects are increased blood pressure, vasoconstriction, acute dehydration, increased heart rate, and jaw tension. Also, with larger amounts, anxiety, insomnia, jitteriness, and reduced coordination may appear. Caffeine reliably improves mental and physical performance at moderate doses, though high doses may negate some of the effects. It's capable of attenuating many of the negative effects of mild sleep deprivation.
Whether you are sleep deprived or just fatigued, caffeine does alleviate or reduce drowsiness. With physical performance, the drug can improve power output, endurance, and other factors of aerobic and anaerobic activity. The exact effects will vary depending on the source of your caffeine, since substances like tea and coffee contain other chemicals that can augment the effects you receive. The stimulation provided by caffeine is generally weaker than what you'd see with amphetamines or other common stimulants. However, at high enough doses, it has a lot of the same negatives like shaking, jaw clenching, and aggravation. When taken too late, caffeine can disrupt the normal mechanism used to induce sleep, so you should avoid taking large amounts it late in the evening. It may cause a crash in energy when it wears off, particularly with higher doses. When used orally, caffeine lasts for 3 to 5 hours. It has an onset of 5 to 30 minutes and is strongest 1 to 3 hours after administration.

Caffeine is a methylated xanthine, with three methyl groups attached to the main xanthine molecule. It functions as a CNS stimulant. It largely provides its effects by working as an antagonist at adenosine receptors. By blocking those receptor sites, adenosine is no longer able to trigger a cascade of effects that'd usually result in drowsiness. The antagonism also ends up increasing respiration, causing vasoconstriction, and other things. Beyond getting rid of drowsiness, caffeine can also provide stimulation through its adenosine antagonism. It's able to increase dopamine, glutamate, and other chemicals that contribute to stimulation. It's not a dopamine agonist, but it does affect dopamine binding since some adenosine receptors are part of complexes that include dopamine receptors. Caffeine has effects on the acetylcholine system through the inhibition of an enzyme that'd normally break down acetylcholine and it can stimulate the release of acetylcholine. On top of all those actions, it stimulates the release of epinephrine and, at high doses, can inhibit GABA, which may be connected to anxiety, insomnia, and negative cardiovascular effects.
Caffeine was only isolated a couple hundred years ago, but it has been used in plant sources for millennia. Chocolate use may date back to 1900 BCE. There are unreliable stories of tea being used as far back as 2700 BCE, though it's at least been drunk since 200 BCE. Coffee appears to be a little more recent. It's been used since at least the 1400s, but probably dates back to before 900 CE. During the 1600s, coffee spread through Europe as a medicine as well as a social and work drink. This resulted in a large coffee trade. It was isolated for the first time in 1819 by Friedlieb Runge. Then, in 1895, it was synthesized by German chemist Hermann Fischer. Over the years, it's been found in dozens of plants. Among which are coffee plants, kola nuts, yerba mate, guarana, and Camellia sinensis, the source of tea.
Caffeine is now the most widely used drug in the world and an estimated 90% of the North American population uses it in one form or another. The drug is used in various ways, such as in a powder or tablets or as a part of chocolate, tea, or coffee. A light oral dose is 20 to 75 mg. A common dose is 75 to 250 mg. And, a strong dose is 250 to 400 mg or more. You should always check your local laws before ordering or using caffeine. Caffeine is legal in the US and generally everywhere else, though there may be some restrictions on the type of products that can be sold. There are some deaths from caffeine on record and it's clear high doses can be unpleasant and very high doses can be lethal. At least one death occurred with around 10 grams, while there are other reports of people surviving up to 50 grams of caffeine. However, for susceptible people, it appears the lowest lethal dose could be just 3 grams. Given the average caffeine user takes about 250 mg per day, they're very far from a truly dangerous amount. The LD50 is believed to be 150 mg per kilogram of bodyweight. That comes out to around 75 cups of coffee. Clearly, you'd have to go out of your way to kill yourself with that amount of coffee. Even with caffeine pills, you'd have to take dozens to obtain a lethal dose. Powder is therefore a more dangerous way to use caffeine, since it's one of the only ways you can mistakenly use a lethal amount. With powder, a lethal dose is contained in just a few teaspoons.

When deaths occur, they usually involve seizure and cardiac arrhythmia. If you use a lower, but still unpleasant dose, such as 400 mg, you may experience caffeine overdose. That state comes with the same negative effects usually found with stronger stimulants, such as insomnia, anxiety, restlessness, disrupted thought and speech activity, rapid irregular heart beats, muscle twitching, and irritability. Beyond that amount, you could experience hallucinations, cardiac issues, and even temporary psychosis before reaching a deadly amount. Dependence does occur with caffeine and because it's such a commonly used drug, many people go through caffeine withdrawal at some point. Depending on your intake, withdrawal includes varying levels of headache, lack of concentration, irritability, and fatigue. Those symptoms usually exist for at least a couple days and sometimes more. It's best to avoid combining caffeine with other stimulants since you're likely to experience greater negative cardiac effects, anxiety, and various overstimulation effects. Also, with some specific drugs like MDMA, caffeine can reliably boost their negative effects.