Sleep is essential for good health, and doctors consistently advise adults to get 7–8 hours of sleep daily. However, new research suggests that the timing of sleep is just as important as the duration. Going to bed at different times every day—sometimes at 10 pm, sometimes at 11 or even later—can quietly increase the risk of several serious diseases.

In today’s fast-paced lifestyle, irregular sleep has become common. Some people stay awake due to work pressure, while others lose sleep because of excessive screen time. Experts warn that frequently changing your sleep schedule can disrupt the body’s internal system and harm long-term health.

What Does the Study Say?

A study published in the science journal Health Data Science tracked the sleep patterns of 88,461 people using wearable devices. The findings revealed that people who slept at inconsistent times or stayed up late regularly were at a higher risk of developing multiple diseases, even if they completed 7–8 hours of sleep.

Expert Insight on Sleep and Disease Risk

Dr. Bipin Kumar Sharma, Consultant Neurologist at Kailash Deepak Hospital, also highlighted similar findings in a study published in Nature Medicine. His research used sleep data (polysomnography) from over 65,000 individuals. The model developed from this data can predict the risk of more than 130 diseases.

Doctors now stress the importance of sleep hygiene, which includes not only sufficient sleep but also consistent and high-quality sleep.

Diseases Linked to Poor and Irregular Sleep

According to experts, poor sleep patterns can increase the risk of:

• Obesity

• High blood pressure

• Heart attack

• Stroke

• Diabetes

• Dementia

Lack of proper sleep also weakens the immune system, making the body more vulnerable to infections.

How Much Sleep Is Ideal?

Experts recommend:

• Adults: 7–9 hours of sleep

• Children & teenagers: Slightly more

Quality sleep means uninterrupted rest without frequent waking or disturbances during the night.

Irregular Sleep Disrupts the Body Clock

Dr. Bharat Kumar Surisetti, Consultant Neurologist at Yashoda Hospitals, Hyderabad, explains that our body follows a circadian rhythm (biological clock). Sleeping at different times disturbs this rhythm, leading to hormonal imbalances.

Hormones such as cortisol, thyroid hormones, and growth hormone follow a fixed daily cycle. Irregular sleep interferes with this cycle, affecting overall health.

Irregular Sleep Increases Hunger and Weight Gain

Poor sleep increases hunger hormones like ghrelin and reduces leptin, leading to:

• Cravings for junk food

• Overeating

• Insulin resistance

• Higher diabetes risk

It also affects mental health, causing irritability, anxiety, depression, and memory problems.

Tips to Fix Your Sleep Schedule

To improve sleep quality and timing:

• Go to bed and wake up at the same time every day

• Avoid tea and coffee in the evening

• Reduce screen time before bed

• Do light exercise in the evening

• Take a warm bath before sleeping