Effect Of Coffee On Your Cardiovascular System

Coffee is a beverage brewed from coffee beans. It is the biggest source of caffeine worldwide.

Coffee contains caffeine, a substance that may boost your mood, metabolism and mental and physical performance.

What Is Caffeine?

Caffeine is a naturally occurring substance that belongs to a group of compounds called methylxanthines.

It is found in over 60 plants worldwide, including the humble coffee bean and the berries of the guarana plant. It's believed that the caffeine in these plants helps to protect them from insect damage. For us humans, it acts as a stimulant and is the most commonly consumed psychoactive substance in the world.

Studies have also shown that it’s safe for most people when consumed in low-to-moderate amounts.

However, high doses of caffeine may have unpleasant and even dangerous side effects.

Research has shown that your genes have a major influence on your tolerance to it. Some can consume much more caffeine than others without experiencing negative effects.

Where Caffeine Is Commonly Found?

There are several common foods and drinks that naturally contain caffeine such as: coffee, tea (both black and green tea) and chocolate. Caffeine can also be added to drinks, such as energy drinks and soft drinks. Both tea and coffee are the most popular beverages worldwide, with coffee being by far the biggest source of caffeine consumption.

 

Effect Of Caffeine On Your Body, Especially The Heart.

Caffeine has multiple effects on the central nervous system, as well as the heart. Typically most people will experience an increase in heart rate, the degree of which differs among individuals. The amount of increase depends on various factors including the amount of caffeine consumed, frequency of consumption, the person's size, physiology, etc. Therefore sensitivity to caffeine is unique to each individual.

The effects of caffeine begin fairly soon after consumption (as soon as 15 minutes) and can last for hours. This, again, varies depending on the plasma concentration of caffeine in the blood.

With regard to the increase in heart rate, as long as someone is not experiencing symptoms such as lightheadedness or dizziness, a temporary, unsustained increase in heart rate should not have any damaging effects. It is generally recommended that no more than one or two cups of coffee/caffeine daily, as higher amounts can sometimes predispose someone to cardiac arrhythmias, if caffeine is consumed in excess.

And please stay away from those energy drinks! It contains a large and unregulated amounts of caffeine and sugar.

Does Caffeine Affect Your Blood Pressure?

Many effects of caffeine, both positive and negative, can be temporary and reversible. For example, some people experience an increase in blood pressure, but this may only last for around four hours. This is therefore reversible, however the long-term impact on overall blood pressure from this temporary effect has not been well researched and remains uncertain.

When caffeine is taken in high doses, it raises your blood level of epinephrine. Epinephrine is also known as adrenalin. In pure forms, epinephrine can increase blood pressure, increase the contractility or force of the heart, and mildly increase the heart rate. In people that are susceptible to abnormal heart rhythms, high doses can cause the heart to develop skipped beats from the upper or lower heart chambers or palpitations from a rapid heart rhythm.

For most people that enjoy caffeinated products our bodies develop tolerance to caffeine over time and the effects on the heart are lessened. Unfortunately for most people that have consumed caffeine for many years without significant changes, the development of new abnormal heart rhythms is usually independent of the caffeine. However, it is always a good idea to consider a trial of stopping caffeinated products if you experience an abnormal heart rhythm or any new heart symptoms. 

When considering your caffeine consumption, caffeine that has been extracted or developed as a chemical, dry product, or pill appears to be more potent in our bodies compared to natural sources of caffeine. For example, the metabolism and exercise performance effects with caffeine are greater with caffeine pills compared to coffee that has a similar level of caffeine. 

How Much Caffeine Is Too Much?

For children and pregnant or breastfeeding women there are strict caffeine guidelines. For children it’s recommended to have no more than 3mg of caffeine per kg of bodyweight. For pregnant and breastfeeding women, it’s recommended they limit caffeine to 200mg or less a day from all sources. For adults who are not pregnant or breastfeeding this equates to a maximum of 400mg of caffeine per day and no more than 200mg in one sitting. 

As food and drink sources of caffeine can vary, so does the caffeine content. Depending on the product and size, 400mg can add up quickly. For example, a cup of coffee tends to have more caffeine than a cup of tea, but this also varies between the type of beans and how they are prepared.

• Caffeine in brewed coffee can range between 95–200mg per cup.

• Instant coffee can range from 27–173mg per cup.

• Black tea contains between 40–120mg per cup.

• Green tea between 25-29mg per cup.

For tea, the amount of caffeine depends on how much water it is brewed in, how long it’s brewed for and the quality of the tea.

Substitute For Caffeine Intake

Sometimes our caffeine consumption from food and drinks can creep up over time. Moderating the amount of caffeine, you have a day can help keep you feeling at your best and prevent any unwanted side-effects.

Here are some simple substitutes to your hot and/or cold drinks to reduce the amount of caffeine you have each day.

• Substitute to decaf coffee and decaf black tea.

• Substitute to naturally caffeine-free herbal tea such as peppermint, chamomile, berry or lemon & ginger.

• Substitute soft drink/energy drink for plain or sparkling water with cucumber and mint for flavouring.

Impact Of Caffeine During Exercise

There are many studies that have examined the impact of caffeine during exercise. When interpreting these studies you must take into account that they were performed in people that were often athletes with healthy hearts and may not apply to people with heart disease. Recently, the Journal of the International Society of Sports Nutrition summarized the effects of caffeine on exercise:

1. Caffeine is effective for enhancing sport performance in trained athletes when consumed in low-to-moderate dosages (~3-6 mg) and overall does not result in further enhancement in performance when consumed in higher dosages (= 9 mg).

 2. Caffeine exerts a greater ergogenic effect [enhancing exercise performance] when consumed in an anhydrous state [contains no water or pill form] as compared to coffee.

3. Caffeine enhances alertness during periods of extended exhaustive exercise, as well as periods of sustained sleep deprivation.

4. Caffeine is ergogenic for sustained maximal endurance exercise, and has been shown to be highly effective for time-trial performance.

5. Caffeine supplementation is beneficial for high-intensity exercise, including team sports such as soccer and rugby, both of which are categorized by intermittent activity within a period of prolonged duration.

6. The literature is equivocal [unclear or ambiguous] when considering the effects of caffeine supplementation on strength-power performance, and additional research in this area is warranted.

7. The scientific literature does not support caffeine-induced diuresis [increased urination] during exercise, or any harmful change in fluid balance that would negatively affect performance.

When you look at the total evidence available, in low to moderate levels, caffeine will likely result in an improvement in both your aerobic exercise ability and tolerance and may also provide benefit in resistance exercise.

In conclusion, if you feel abnormal heart beats or rhythms if you start using caffeine or start using high doses then stop using it. You may have to wait days after the caffeine exposure for your heart to go back to normal. If it doesn’t or the symptoms are severe, you should contact your doctor. If you develop these symptoms after years of using similar levels of caffeine, then your heart symptoms are likely caused from other sources. If you use caffeine to improve your exercise ability, use relatively low doses. The accumulative evidence with low to moderate amounts of caffeine and exercise suggests it is beneficial and relatively safe. If you have prior heart disease or abnormal heart rhythms, talk to your physician before starting an endurance exercise program in which you want to also use caffeine to enhance your performance.