Experts Explain How Staying Up Past Midnight Disrupts Your Heart’s Natural Rhythm

Most people see late-night scrolling, after-hours work, or binge-watching as harmless habits. But new evidence suggests the body may not be as forgiving. A large-scale Journal of the American Medical Association

(JAMA) study has found that going to bed late, even if you still get eight hours of sleep, may increase the risk of heart failure by a striking 56 per cent. The findings highlight a critical but often overlooked truth: the timing of sleep may matter as much as the duration.

Why When You Sleep Matters More Than You Think

The JAMA study, which examined thousands of adults, revealed a clear pattern – irregular sleep schedules and late sleep onset were independently associated with higher risks of heart attack, stroke, heart failure, and overall cardiovascular mortality.

As Dr. Amitabh Poonia, Consultant Cardiology, Kailash Deepak Hospital, Delhi, explains, “Scientific research consistently highlights the strong connection between sleep patterns and cardiovascular health. Even those who manage eight hours of rest but sleep after midnight face greater heart-related risks.”

He notes that the study’s strength lies in proving that sleep timing itself can be a standalone risk factor. Supporting data from twin-based research also found that siblings with delayed sleep patterns had a higher chance of heart disease despite shared lifestyles.

How Late Nights Impact The Heart

Cardiologists believe the reason is rooted in our biology. The heart follows a circadian rhythm, and staying awake late deregulates everything from hormones to blood pressure.
According to Dr. Dixit Garg, Consultant – Interventional Cardiology, Manipal Hospital, Gurugram, “Late-night wakefulness often leads to hormonal imbalances, increased stress levels, and higher blood pressure. Over time, these factors contribute to endothelial dysfunction and inflammation, which increase the risk of heart failure.”

When bedtime slips toward midnight or beyond, the effects accumulate:

• Higher cortisol and stress levels
• Increased nighttime blood pressure
• Inflammation in blood vessels
• Disrupted metabolic pathways
• Poorer diet and screen habits
• Reduced next-day physical activity

Dr. Poonia adds that late sleep patterns often go hand in hand with smoking, stress, unhealthy diets and excessive screen time, all of which add to the cardiovascular burden.

Building A Heart-Healthy Sleep Routine

The experts emphasise that improving sleep hygiene is a simple but powerful intervention.

Dr. Garg recommends:

• Sleeping and waking at consistent times
• Ensuring 7–8 hours of uninterrupted sleep
• Reducing blue-light exposure before bed
• Seeking medical guidance for insomnia or shift-work fatigue

Meanwhile, Dr. Poonia advises aiming for sleep onset between 10 and 11 PM, paired with healthier eating habits and stress management.

Our body is wired for rhythm, not randomness. Aligning sleep with natural circadian cues may be one of the easiest ways to reduce long-term cardiovascular risk. Consistent, early sleep may not feel revolutionary, but for the heart, it could be transformative by offering protection that no late-night productivity streak can justify.