Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Thanks for visiting. Don't miss your FREE gift. Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health , plus the latest advances in preventative medicine, diet and exercise , pain relief, blood pressure and cholesterol management, and more. Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss Stay on top of latest health news from Harvard Medical School.
Recent Blog Articles. Health news headlines can be deceiving. Elevated blood pressure is a risk factor for heart attack and stroke because it may damage arteries over time, restricting the flow of blood to your heart and brain. High caffeine intake has also been shown to raise blood pressure during exercise in healthy people, as well as in those with mildly elevated blood pressure 37 , Therefore, paying attention to the dosage and timing of caffeine is important, especially if you already have high blood pressure.
Summary: Caffeine seems to raise blood pressure when consumed at high doses or prior to exercise, as well as in people who rarely consume it. It may also lead to altered heartbeat rhythm, called atrial fibrillation, which has been reported in young people who consumed energy drinks containing extremely high doses of caffeine In one case study, a woman who took a massive dose of caffeine powder and tablets in an attempted suicide developed a very rapid heart rate, kidney failure and other serious health issues Indeed, even some people with heart problems may be able to tolerate large amounts of caffeine without any adverse effects.
In one controlled study, when 51 heart failure patients consumed mg of caffeine per hour for five hours, their heart rates and rhythms remained normal Regardless of the mixed study results, if you notice any changes in your heart rate or rhythm after drinking caffeinated beverages, consider decreasing your intake.
Summary: Large doses of caffeine may increase heart rate or rhythm in some people. These effects appear to vary greatly from person to person. If you feel them, consider reducing your intake.
However, they can also have the opposite effect by leading to rebound fatigue after the caffeine leaves your system. One review of 41 studies found that although caffeinated energy drinks increased alertness and improved mood for several hours, participants were often more tired than usual the following day Of course, if you continue to drink lots of caffeine throughout the day, you can avoid the rebound effect.
On the other hand, this may affect your ability to sleep. Summary: Although caffeine provides energy, it can indirectly lead to fatigue when its effects wear off. Aim for moderate caffeine intake to help minimize rebound fatigue. You may have noticed that you need to urinate frequently when you drink more coffee or tea than usual. In one study, 12 young to middle-aged people with overactive bladders who consumed 2 mg of caffeine per pound 4. In addition, high intake may increase the likelihood of developing incontinence in people with healthy bladders.
One large study looked at the effects of high caffeine intake on incontinence in more than 65, women without incontinence. Those who consumed more than mg daily had a significantly increased risk of incontinence, compared to those who consumed less than mg per day If you drink a lot of caffeinated beverages and feel that your urination is more frequent or urgent than it should be, it may be a good idea to cut back on your intake to see if your symptoms improve.
Summary: High caffeine intake has been linked to increased urinary frequency and urgency in several studies.
Reducing your intake may improve these symptoms. Meredith explains this in the following terms:. Many food and drink products now contain added caffeine to enhance their stimulating effects, such as jellybeans, waffles, syrup, and chewing gum. While moderate consumption of caffeine is unlikely to produce harmful effects in most people, reactions to the stimulant depend on highly individual factors, such as genetics and accompanying lifestyle choices. People should be mindful that they are consuming a psychoactive substance when they use caffeine.
Black tea is a popular beverage worldwide. However, it may also have an effect on health. Learn more about the benefits and risks of drinking black…. Green tea may benefit the heart, aid weight management, and soothe the skin.
Learn more about the potential benefits and risks here. Decaffeinated coffee, or decaf, is similar to regular coffee but contains very little caffeine. Research suggests that drinking decaf is not harmful…. Do you enjoy tea for its flavor or the soothing feeling brought by holding a steaming cup? In this Spotlight, we tell you which brews are best for…. Caffeine stimulates the nervous system. People often consume it to stay alert, but how long do effects last, and how does it impact sleep?
Is caffeine bad for you? Natural stimulant Benefits Adverse effects Variation Addiction and withdrawal Young people Takeaway Caffeine is a psychoactive substance that occurs naturally in coffee. Caffeine is a natural stimulant. Share on Pinterest Caffeine can help counteract tiredness. Matthew Chow, a neurologist and assistant clinical professor at UC Davis, to get the lowdown on caffeine intake.
He told me everything you need to know, including who should stay away from the stuff, what health benefits it could provide and how to know when you need to quit. Chow explains that children should refrain from ingesting any caffeine, as well as people with heart disorders specifically arrhythmias or peptic ulcer disease.
The main reason that kids should stay away from caffeine is because they tend to drink it in the form of sodas and energy drinks. These beverages are marketed toward children, but contain high levels of sugar and can contribute to childhood obesity and health disorders.
The caffeine in those beverages could potentially be harmful when concentrated in childrens' smaller bodies as well, so Chow recommends that kids don't consume any at all. Chow also notes that anyone who is pregnant should stay away from caffeine, though the evidence behind this rule of thumb is inconclusive. There are differing opinions about this guideline in the medical community -- Dr. Deep Bhatt of Weill Cornell Medicine tells CNET in an email statement that pregnant people should keep their caffeine intake below milligrams per day.
Anyone who is concerned about their caffeine intake while pregnant should talk to their doctor. For anyone who's cleared to drink caffeine, the upper limit is about milligrams per day. That equals four cups of coffee , 8 cups of green tea or 10 cans of soda. However, this guideline is highly personal -- if you feel jittery or uncomfortable when drinking caffeine, consider limiting yourself further.
0コメント