Staying up late might seem harmless or even productive but consistently falling asleep after midnight can lead to serious health consequences, warns California-based gastroenterologist Dr. Saurabh Sethi.
Well known for sharing medical advice with his 500K+ followers on TikTok (@doctorsethimd), Dr. Sethi recently posted a video that’s gained thousands of views, highlighting the four key ways late bedtimes harm the body and mind.
“If you regularly stay up past midnight, you might experience several health issues,” he explains, noting that this habit usually means getting less than the recommended 7–9 hours of sleep.
Although sleep needs vary, quality and duration are essential for physical recovery, hormonal balance, and mental clarity. Here’s how a late bedtime can impact your health:
1. Weight Gain
Dr. Sethi points to weight gain as the first consequence of sleep deprivation. Inadequate sleep disrupts hunger hormones like ghrelin and leptin, leading to cravings for unhealthy, high-calorie foods.
Research published in JAMA supports this, showing a 20% higher risk of obesity in individuals who sleep after midnight compared to those who sleep earlier (between 8–10pm).
2. Mood Decline
Going to bed late has been linked to worsening mood. A study from Stanford Medicine found that sleeping before 1am is associated with better mental health, regardless of whether you’re naturally a night owl or early bird. Those who sleep after 1am show a higher risk of depression and anxiety.
3. Increased Stress
Sleep timing also affects stress hormone levels, especially cortisol. A lack of early-night deep sleep can leave the body in a constant low-level stress state, impacting both mental resilience and immune function.
4. Poor Focus and Thinking
Finally, Dr. Sethi notes that staying up past midnight can impair cognitive performance, especially concentration and memory. This is because the deepest and most restorative sleep usually occurs in the earlier hours of the night.
A University of Arizona study found that early sleep promotes stronger memory consolidation and sharper focus throughout the day.
Additional Risks: Heart and Hormonal Health
Late sleepers may also face increased cardiovascular risks. Research from the British Heart Foundation found that people who fall asleep between 10–11pm have the lowest risk of heart and circulatory diseases. A related study in the European Heart Journal confirmed this link.
Dr. Sethi’s Final Advice:
“To improve your overall health including hormone balance, gut health, liver health, and mood—aim to sleep before midnight.”
Getting to bed earlier isn’t just about waking up refreshed it’s a long-term investment in your mental and physical well-being.
