Most people trying to protect their heart focus on the same three things. Eat better, move more, quit smoking. And those things genuinely matter. But there’s a fourth piece that almost never comes up at the dinner table or in a doctor’s checklist, and it turns out to be just as important as the other three combined. That piece is sleep.Dr. Hemanth Kaukuntla, Senior Cardiothoracic Surgeon at Renova Century Hospital, has spent enough time in operating rooms and consultation chambers to notice a pattern. Patients walk in convinced they’re doing everything right. “You eat healthy, exercise regularly, maintain a healthy weight and avoid smoking. You may think you are doing everything possible to protect your heart,” he says. But according to him, there’s one important piece of the puzzle that is often overlooked, and it’s sleep. Growing scientific evidence now shows that poor sleep can increase cardiovascular risk, even in people who otherwise lead a healthy lifestyle.This isn’t a fringe opinion floating around wellness circles either. The American Heart Association has folded sleep directly into its official framework for heart health, listing it as one of its “Life’s Essential 8” measures of cardiovascular wellbeing. Its latest scientific statement, published in 2025, makes a point worth sitting with. Healthy sleep is not simply about the number of hours we spend in bed. Sleep regularity, continuity, timing, quality and daytime alertness also matter. And the statement doesn’t stop at vague warnings either. Poor sleep is associated with high blood pressure, abnormal cholesterol, inflammation, impaired glucose control, obesity, heart disease, stroke and cardiovascular mortality. Read that list again and it starts to look uncomfortably similar to a rundown of heart disease’s greatest hits.
What actually happens to your heart while you sleep badly
So why does something as passive as sleep carry this much weight for an organ that’s working around the clock anyway? Dr. Kaukuntla breaks down what’s happening on a mechanical level. During normal sleep, particularly deep sleep, heart rate and blood pressure generally fall, giving the cardiovascular system a period of relative rest. That dip isn’t incidental. It’s the one stretch in a 24-hour cycle where the heart genuinely gets to slow down and recover from the demands of the day.The trouble starts when that recovery window keeps getting interrupted. Repeated sleep disruption can interfere with this recovery and increase activity of the body’s stress-response system, he explains. And it’s not a one-off effect either. Over time, inadequate or fragmented sleep may contribute to higher blood pressure, inflammation and metabolic disturbances, all important risk factors for cardiovascular disease. In other words, it isn’t one rough night that does the damage. It’s the slow accumulation of nights where the heart never quite gets its scheduled break.
Is there a magic number of hours?
Everyone wants a single figure to aim for, and there’s actually decent research pointing toward one, though the shape of that research might surprise you. A large systematic review and dose-response meta-analysis found a U-shaped relationship between sleep duration and cardiovascular outcomes, with the lowest risk occurring at around seven hours of sleep per night. The U-shape is the interesting bit here. Both substantially shorter and longer sleep durations were associated with increased cardiovascular risk, meaning oversleeping isn’t the safe zone people sometimes assume it to be. Seven hours, according to this data, sits right at the low point of that curve.But hours on a clock only tell part of the story. Someone can spend a full eight hours lying in bed and still walk around the next day running on empty. It is not only about sleep duration, Dr. Kaukuntla points out. Someone may spend eight hours in bed but still have poor-quality sleep. Frequent awakenings, irregular bedtimes, difficulty falling asleep or excessive daytime sleepiness can all indicate unhealthy sleep. So the number on the alarm clock is really just one input among several, and arguably not even the most important one.
The condition that gets brushed off as “just snoring”
There’s one sleep condition Dr. Kaukuntla is particularly keen to flag, mostly because it hides in plain sight inside so many Indian households. One particularly important condition is obstructive sleep apnoea, in which breathing repeatedly stops or becomes restricted during sleep. The warning signs are rarely subtle. Loud snoring, choking or gasping at night and excessive daytime sleepiness should not simply be dismissed as normal ageing or tiredness, he says. And yet that’s precisely what tends to happen. A family member’s thunderous snoring becomes a running household joke rather than a reason to book an appointment, even though it can be quietly working against the heart every single night.
Can better sleep actually undo the damage?
Here’s where the conversation takes a genuinely encouraging turn. Poor sleep raising cardiovascular risk is one thing to accept. But does fixing it actually move the needle back the other way? An encouraging finding from newer research is that improving sleep may improve cardiovascular risk factors, Dr. Kaukuntla says. He points to a 2026 systematic review and meta-analysis in European Heart Journal – Open, which examined behavioural sleep interventions and found that interventions designed to improve sleep were associated with reductions in blood pressure. This suggests that improving sleep may be more than simply a way of feeling refreshed, he adds. It could potentially form part of cardiovascular prevention in its own right.That said, he’s careful not to oversell sleep as some kind of standalone fix that lets people off the hook on everything else. Sleep does not replace exercise, a healthy diet or prescribed medication, he clarifies. Rather, it complements them. So nobody gets to trade their morning walk for an extra half hour under the blanket and call it a wash. The point isn’t substitution, it’s addition.
The updated prescription
For years, the standard heart-health advice has stayed more or less the same: eat well, exercise, don’t smoke. Dr. Kaukuntla thinks it’s time that list got a fourth line. We have traditionally told people to eat well and exercise to protect their hearts, he says. Perhaps the modern prescription should be eat well, move well, sleep well. Because even the healthiest heart needs time to rest.His practical advice for readers is fairly simple to state, even if it’s harder to follow through on. Aim for seven to nine hours of good-quality sleep each night, and pay attention to regular sleep and wake times, not just the total count of hours. Persistent snoring, gasping, insomnia or daytime sleepiness deserves medical attention rather than a shrug. And no matter how disciplined your diet or how consistent your workouts are, a healthy diet and regular exercise cannot completely compensate for chronic poor sleep. Protecting your heart, in the end, means protecting your sleep too, right alongside everything else you’re already doing to take care of it.
