For millions of people, the day begins with a cup of coffee. Now, the largest review yet from the American Heart Association (AHA) offers reassuring news: for most healthy adults, drinking up to 400 mg of caffeine a day — roughly three to five cups of regular black coffee — appears to be safe and may even lower the risk of heart disease, stroke and heart failure.The caveat? Not all caffeine is created equal. Energy drinks and caffeine shots, which pack far more caffeine into a much smaller serving, may do more harm than good.Explains Dr Balbir Singh, Chairman, Cardiac Sciences, Max Healthcare, who himself has black coffee through the day, “In fact, this latest review clears the misconception that drinking coffee could affect those who have atrial fibrillation, the most common abnormal heart rhythm, in which the heart’s upper chambers (atria) beat rapidly and irregularly, increasing the risk of stroke, heart failure and other cardiovascular complications. But beneficial compounds in coffee outweigh the mild stimulant effects of caffeine at moderate doses. In fact, they are anti-inflammatory and improve blood vessel function.”He also demolishes the myth that drinking black coffee raises blood pressure. “The BP spike is very temporary and then goes down, so one cannot say that coffee-drinking has a significant long-term effect on BP. This is the reason why we advise people to measure their BP for trustworthy readings 30 to 45 minutes after they have had their cup of coffee. It is for the same reason that we advise people not to have coffee before they undertake any intense physical exercise or strenuous activity which can raise your BP. Even then the BP response varies from person to person. Some studies have shown that in habitual coffee drinkers, the spiral effect reduces over time as they develop tolerance to the brew, compared to non-regular drinkers. Others attribute the BP spike to coffee spurring the release of extra adrenaline,” he adds.Must Read | Your morning coffee does more than wake you up, may rewire your cells: StudyHowever, Dr Singh clarifies that this finding applies only to black coffee and not coffee with a lot of milk and sugar. “That’s harmful for the body because it raises calories. Latest research says sweeteners too raise the risk of blood clotting, which is worrisome for heart health,” he says. Excerpts from an interview:Coffee gets a clean bill of heart healthThe latest scientific statement from the American Heart Association, published in Circulation, quotes experts as saying that moderate coffee consumption does not increase cardiovascular risk for most adults. In fact, drinking black coffee without added sugar, syrups or cream was associated with a lower risk of several conditions, including heart disease, stroke, heart failure and Type 2 diabetes.The recommended upper limit remains 400 mg of caffeine a day, roughly equivalent to three to five 8-ounce cups of brewed coffee, depending on its strength.Why energy drinks are a different storyStory continues below this adWhile coffee appears relatively safe in moderation, the same cannot be said for energy drinks. Many energy drinks and concentrated “energy shots” contain three to four times more caffeine per ounce than regular coffee, often combined with stimulants and other additives that may speed up caffeine absorption.Also Read | Knowledge Nugget | Coffee in India: History, Geography and key facts for UPSC AspirantsThe review found that high doses of caffeine from energy drinks were linked to increased blood pressure and a greater risk of abnormal heart rhythms. Even healthy young adults have experienced heart rhythm disturbances after consuming large amounts of these beverages.More benefits than just caffeineInterestingly, researchers say coffee’s health benefits may not come from caffeine alone. Coffee contains hundreds of natural compounds with antioxidant and anti-inflammatory properties that may help protect blood vessels and reduce inflammation. This may explain why coffee often performs better in studies than caffeine consumed through supplements or energy drinks.At the same time, scientists caution that adding generous amounts of sugar, flavoured syrups, whipped cream or sweetened creamers could offset some of coffee’s potential health benefits.Story continues below this adYour body doesn’t process caffeine like everyone else’sOne reason caffeine research remains complicated is that people respond to it very differently. Genetics, age, liver metabolism, medications and even how often someone drinks coffee influence how quickly caffeine is broken down. Some people can enjoy several cups without noticeable effects, while others experience palpitations, anxiety or poor sleep after a single cup.Also Read | ‘Drink your coffee, but only in the morning’: What a new study saysThe review notes that caffeine typically reaches peak levels in the bloodstream within an hour, though its effects can last much longer in sensitive individuals.The sweet spot may be two to four cupsAcross multiple studies, drinking two to four cups of coffee a day was consistently associated with the greatest reduction in the risk of heart disease, heart failure and stroke.Story continues below this adHowever, the evidence becomes less certain beyond that level. Some studies suggest consuming more than four cups daily may increase the risk of heart failure in certain people, reinforcing the message that moderation still matters.Filtered coffee may be better than French pressThe way coffee is prepared also matters. Unfiltered coffee — including French press, Turkish coffee, boiled coffee and some espresso preparations — contains higher amounts of cafestol, a naturally occurring compound that can raise LDL (bad) cholesterol.Paper-filtered coffee and instant coffee contain much lower amounts of cafestol and may, therefore, be the better choice for people concerned about cholesterol.The takeawayThe new guidance isn’t a licence to drink coffee endlessly. Instead, it offers reassurance that moderate coffee consumption can fit comfortably within a heart-healthy lifestyle for most adults.Story continues below this adAt the same time, experts stress there is no universal caffeine prescription. People with heart rhythm disorders, uncontrolled high blood pressure, pregnancy, sleep problems or sensitivity to caffeine should discuss their intake with their doctor. For the rest, do not abandon the diet, sleep and exercise routine.