Wakey Wakey! It’s time for your morning dose of caffeine! Whether you choose tea or coffee as your beverage of choice, it's caffeine that you are reaching out for. Caffeine must be one of the most popular and unifying food ingredients around the world, but how healthy is it? Does it impact your vitals adversely? What about caffeine and blood pressure? Let’s find out.
Caffeine is a natural stimulant that is generally found in tea, coffee, kola nuts, cacao plants and guarana plants. It can also be manufactured synthetically. Caffeine works by blocking the effects of adenosine, which is a neurotransmitter that relaxes your brain and induces tiredness. Adenosine levels increase as the day progresses, making you more tired and causing sleepiness.
Caffeine helps you stay awake by connecting to adenosine receptors in the brain without activating them. This blocks the effects of adenosine and reduces tiredness. It may also increase the blood levels of another neurotransmitter called adrenaline and the brain activity of the neurotransmitters dopamine and norepinephrine.
Thus, caffeine can help you feel awake, alert, and focused through a combination of these mechanisms.
Several drinks or beverages contain caffeine as the main stimulant. Some drinks that contain caffeine include:
1 cup (about 240 ml) of brewed black tea contains 47.4 mg of caffeine. Further, 1 cup (about 240 ml) of coffee contains 94.8 mg of caffeine.
Caffeine is generally considered safe for consumption and beneficial for health if consumed within the recommended quantity. The United States Department of Agriculture (USDA) and the European Food Safety Authority (EFSA) state that a daily intake of 400 mg of caffeine is safe. Pregnant women should limit their daily intake of caffeine to less than 200 mg.
The health benefits of caffeine and side effects due to excessive consumption are defined later in the blog.
Research on the connection between caffeine and blood pressure is still ongoing. The response of blood pressure to caffeine also appears to differ from person to person. Studies suggest that caffeine can cause a spike in your blood pressure for a short duration of time. This effect was observed for up to three hours after consumption of caffeine.
Caffeine has a vasoconstrictor effect. Vasoconstriction is when your blood vessels become narrow. This increases the resistance to blood flow and raises your blood pressure levels. Research suggests that caffeine exerts this effect by interacting with different receptors in your brain.
Other studies suggest that caffeine stimulates your adrenal glands to release adrenaline. Adrenaline is a stress hormone, which increases your heart rate and blood pressure.
It has been observed that some individuals who regularly drink caffeinated beverages have a higher average blood pressure than those who do not consume caffeine. However, some regular drinkers of caffeinated beverages may develop a tolerance to caffeine and have no long-term effect on their blood pressure.
If you love tea or coffee and do not want to give it up, do not worry. Caffeine consumption within the recommended limits does not appear to have adverse effects on blood pressure.
Caffeine may cause a short but noticeable increase in your blood pressure for up to 3 hours after consumption, especially if you do not drink caffeinated beverages regularly. For some individuals who have developed caffeine tolerance, there may be no significant impact on blood pressure levels.
Though caffeine may increase your blood pressure temporarily, this effect does not seem to extend for the long term. The long-term effect of caffeine is different for different individuals.
For some people who drink caffeinated beverages habitually, their blood pressure levels are higher than those who do not consume caffeine. Others who regularly drink caffeinated beverages develop a tolerance to caffeine and thus it does not have a long-term effect on their blood pressure levels.
Even if you have high blood pressure, research suggests that daily coffee consumption may not have a significant impact on your blood pressure levels. In fact, as per a study, increased coffee consumption is associated with a small decrease in hypertension.
It is advisable to consume caffeine in moderation irrespective of your health condition. If you have high blood pressure, ask your healthcare provider for advice about your caffeine consumption.
It is advisable to consume caffeine at least an hour after waking up, with mid to late morning (9.30 am to 11.30 am) being considered to be the most suitable time for caffeine consumption.
This is because your cortisol (a stress hormone) levels are highest during the initial 30 to 45 minutes of waking up and decrease through the rest of the day. Consuming caffeine early in the morning may not be as beneficial as consuming it during the daytime as your cortisol levels may alter the energising effects of caffeine.
Consuming a caffeinated beverage about 30 to 60 minutes before a workout or sporting event can help optimise caffeine’s beneficial effects on exercise performance.
Further, the stimulating effects of caffeine last for about 3 to 5 hours. Thus, consuming caffeine too close to bedtime can cause sleeping problems. You should avoid caffeine consumption at least 3 to 5 hours before going to bed.
As per the USDA and EFSA, you should not have more than 400 mg of caffeine a day, which equals about 4 to 5 cups of coffee or tea.
Also, it is advisable to consult with your doctor before consuming caffeinated beverages if you are pregnant, trying to conceive, breastfeeding, or taking medication for an existing health condition such as hypertension, diabetes, etc.
When consumed within the recommended quantity, caffeine has several health benefits, including:
Excessive intake of caffeine (beyond 400 mg every day) can cause side effects including:
If you do not want to consume caffeinated beverages due to their effect on your body or mind, you can look for non-caffeinated alternatives too:
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