Caffeine is a natural psychostimulant, a substance that affects the central nervous system (CNS). Considering the fact that we consume it daily by drinking coffee, tea and cola, it's no wonder why people call it the world's most famous psychoactive drug. Naturally, it can be found in leaves and seeds of many plants. Out of many physiological effects that caffeine has on the human body, one of the most important ones must be its effect on heart rate.

How Does Caffeine Affect Heart Rate?

Your heart will beat faster. It has been proven that caffeine has the ability to increase heart rate by somewhere around three beats per minute.

When you ingest caffeine, it goes to your small intestine from where it enters the bloodstream and starts to stimulate your central nervous system. It will stimulate receptors that can block an enzyme called phosphodiesterase. This enzyme, with the help of an enzyme called cyclic AMP, is in charge of keeping the heart rate in check. Therefore, your pulse starts to increase. 

The effect that caffeine has on you is determined by your size and your tolerance to it. For example, if you weigh more and consume large doses of caffeine every day, it is natural that your heart rate won't be affected so much, compared to the heart rate of a slim person who rarely consumes caffeine.

How Long Will the Effect Last?

The change in heart rate starts in 15 minutes after the consumption of caffeine, and takes about 6 hours to wear off, after which the ingested caffeine leaves the body along with urine.

Warning

But how does caffeine affect heart rate of cardiovascular patients? Well, caffeine will have a negative effect on such people's heart function and cause arrhythmia that could pose a threat to people suffering from atrial fibrillation.

In fact, even those perfectly healthy people could experience side effects of caffeine; therefore, try to restrict the consumption of caffeine to 250 milligrams per day, which is about 3 cups of coffee.

How Does Caffeine Affect Your Body?

1. Central Nervous System

Caffeine is a stimulant of the central nervous system, and as such, it makes one more alert. It also makes people feel more awake, so it's not a surprise that it is used as the main component of drugs made to fight drowsiness.

Despite its positive effects, it actually has more negative ones. For example, if you consume too much caffeine, there's a good chance it will give you a headache; if you have difficulties falling asleep at night, it will make your condition worse; if you are addicted to it, the withdrawal will cause anxiety and tremors; and caffeine overdose can even lead to death.

2. Digestive and Excretory Systems

Along with the question of "How does caffeine affect heart rate?" the question of how it affects the digestive system arises.

• Caffeine is known to increase the acidity of the stomach, thus causing the heartburn. It also has a diuretic ability, which means that drinking coffee when you are thirsty is only going to make you thirstier. Large amounts of caffeine should be avoided by those who exercise regularly since it can cause a loss of water that can lead to dehydration.
• In case you have stomach problems such as ulcers, it is best to consult your doctor prior to caffeine consumption as caffeine can worsen the condition.
• Caffeine withdrawal symptoms can include nausea and vomiting.

3. Skeletal and Muscular Systems

Large amounts of caffeine inhibit the proper absorption of calcium, which might lead to osteoporosis.

Caffeine withdrawal symptoms include muscle ache, and caffeine overdose can cause twitching of muscles.

4. Reproductive System

Once consumed, caffeine travels through your bloodstream, passes over to the placenta, and affects heart rate of your baby. A large amount of it can slow down the growth of the fetus, and unfortunately, increase the chances of miscarriage. 

Caffeine can also be one of the causes of painful breast lumps and can have a negative effect on the production of estrogen, thus reducing your chances of getting pregnant. So if you plan on conceiving a baby, or perhaps have breast lumps, you'd better talk to your health care professional about the safety of caffeine.

5. Circulatory System

How does caffeine affect heart rate? This question has been answered, and we know that heart belongs to the circulatory system. Then what are other effects on the circulatory system? Caffeine consumption often results in the increase of blood pressure, no matter whether you suffer from hypertension or not. What causes this phenomenon remains unanswered. While some scientists stand by the theory that caffeine blocks a hormone in charge of keeping your arteries expanded, others believe the theory that its consumption leads to the increased release of adrenaline which can cause high blood pressure.