Sleep, Light, and Your Heart: What the Melatonin Buzz Misses

You may have seen the headlines about melatonin and heart risk. As a cardiologist, I read them too. 

The study behind those headlines was only a short summary of early data, not a full scientific paper. There’s still a lot we don’t know.

But one thing we do know is this: sleep matters. It affects how your heart rests, repairs, and recovers every single night. 

So, instead of focusing on one supplement, let’s talk about what really supports healthy sleep—and why it’s so important for your heart.

How sleep and the heart work together

Good sleep is like a nightly tune-up for your heart.

When you fall into deep sleep, your blood pressure drops, your heart rate slows, and your body repairs itself. This happens through your circadian rhythm, your body’s natural 24-hour clock that tells your hormones when to rise and fall.

When that rhythm gets thrown off—by stress, late-night screens, or light in your bedroom—your heart doesn’t get the rest it needs.

Even small disruptions, like sleeping with a TV or lamp on, can keep your body from fully relaxing. That means your blood pressure may not dip overnight the way it should, and over time, this can strain your heart.

Your natural sleep rhythm is guided by light and dark. Darkness signals your body to rest, and morning light tells it to wake. When that rhythm is disrupted, your heart has to work harder.

That brings us back to melatonin, the hormone your body naturally releases in the dark. It’s your internal signal that it’s time to rest. 

The truth about the melatonin study

When I read through the new study warning about melatonin and heart risk, I realized the story wasn’t exactly what it seemed.

It showed an association, not cause and effect. Most people taking melatonin were already struggling with serious sleep issues, and sleeplessness itself is a known heart risk factor.

So, it may not be melatonin that’s the problem. It could be the poor sleep that led people to take it in the first place.

For now, there’s no clear proof that melatonin causes heart issues. But there’s plenty of research showing that poor sleep does.

Heart disease doesn’t just happen overnight, it builds slowly through everyday choices. Habits like what you eat, how you move, how you manage stress, and how well you sleep all shape your heart over time.

Simple steps for heart-healthy sleep

Improving your sleep can help your heart stay strong and young. Here are four ways you can do this, starting tonight. 

1. Keep it dark

Your body starts releasing its own melatonin when it’s dark. Any kind of light—blue, white, even a nightlight—tells your brain it’s daytime.

Try this:

• 30-60 minutes before bedtime, turn off TVs, phones, and glowing clocks
• Use blackout curtains or an eye mask to block outside light
• Keep devices out of the bedroom if you can, or set them to “Do Not Disturb” so your sleep stays uninterrupted

2. Protect your rhythm

We may live with technology, but our hearts still run on ancient rhythms.

Try this:

• Go to bed and wake up around the same time each day
• Aim for about seven hours of sleep
• Dim lights an hour before bed so your body knows it’s time to wind down

3. Notice your blood pressure patterns

When you’re getting good rest, your blood pressure naturally dips overnight. That “nighttime drop” is one of the signs your heart is relaxing the way it should.

I’m not suggesting you check your blood pressure in the middle of the night, but you can look for patterns over time.

Check your blood pressure regularly in the Hello Heart app, especially at consistent times in the morning or evening. If your numbers stay high day after day, that may mean your body—and your heart—aren’t getting the recovery they need.

That kind of early awareness is powerful. When you spot small changes early, you can talk with your doctor and make adjustments before they become bigger problems.

4. Support sleep naturally

You don’t need a pill to rest well, just a few smart habits.

Try this:

• Avoid caffeine after lunch
• Limit alcohol before bed—it disrupts deep sleep
• Create a short “wind-down” routine, like gentle stretching or reading

Sleep isn’t just rest, it’s repair. Your heart needs that downtime to recover from the day.

Focus on small improvements. The goal is to make your next night a little better than the one before.

When to talk to your doctor

If you rely on sleep aids or melatonin most nights—or still feel tired after seven to eight hours—check in with your doctor. Sometimes insomnia is a sign of something deeper, like sleep apnea or high blood pressure.

Pay attention to your patterns. The more you understand what affects your rest, the sooner you can take steps that truly help.

The bottom line

Good sleep doesn’t have to be perfect, just intentional. A dark, calm space and a steady sleep schedule are some of the simplest ways to keep your heart strong and young.

Your heart is resilient. When you give it the rest it needs, it can recover and grow stronger.

Track your sleep and blood pressure together in your Hello Heart app. Small steps tonight can mean a healthier heart tomorrow. 

👉 Ready to see how rest shows up in your numbers?

‍Open your Hello Heart app, take a quick reading, and add a short note about how you slept. Small, calm moments matter, and your data will show it.