But this manner of thinking comes at a significant cost, as human biology tells a very different story of what sleep deprivation actually does to our health. Every bodily system that sustains health depends on sleep. During sleep, the body recalibrates metabolism and strengthens immune defences to protect from disease-causing factors such as bacteria and viruses. Emotional balance and cognitive clarity also depend heavily on consistent rest.

Longevity conversations today often focus on breakthroughs in medicine such as precision diagnostics, new therapies and biotechnology. These innovations continue to extend human lifespan. Yet one of the most powerful forces shaping how well we age remains something far simpler. The quality of sleep we get each night plays a decisive role in determining whether longer lives translate into healthier lives.

World Sleep Day offers an opportunity to reflect on this quiet biological foundation.

Living longer raises a new question about how well we age

Human beings now live longer than any generation before us. In Singapore, life expectancy exceeds 83 years, placing the country among the longest lived societies in the world. It goes without saying that longer life is an extraordinary achievement of modern medicine and public health.

However longevity has introduced a new challenge. Healthspan, which refers to the number of years lived in good health, has not expanded at the same pace as lifespan. Many people now spend the final decade of life coping with chronic illness or reduced independence.

Data from the World Health Organization show that globally there is roughly a ten year gap between life expectancy and healthy life expectancy. Closing that gap has become one of the central ambitions of longevity science.

Researchers studying lifestyle and longevity medicine now highlight six pillars that support long term health: nutrition, movement, sleep, stress management, avoiding harmful substances and maintaining meaningful social connections.

Among these pillars, sleep often receives the least attention, even though biological recovery depends heavily on sufficient bodily rest.

What happens inside the body during sleep

The recommended amount of sleep, on average, for healthy adults falls between 7 and 9 hours each night, according to Bupa. During this period, sleep does not shut down the body. Instead, many essential repair processes are activated, especially when we enter the realm of what we call “deep sleep”.

One of the most important discoveries in recent years is the role of something known as the glymphatic system, an impressive waste-clearance system facilitated by the act of sleeping. This network functions as a cleaning system for the brain, helping remove metabolic waste that accumulates during the waking hours. Scientists have even shown that the brain clears proteins called beta-amyloid, which are linked to Alzheimer’s disease, during periods of deep sleep.

Sleep also plays a key role in regulating hormones that influence growth, tissue repair and metabolism. Immune cells adjust their response to inflammation while the brain strengthens neural connections formed as a result of new memories collected during the day.

A meta analysis published in the European Heart Journal found that individuals sleeping fewer than six hours per night face significantly higher risks of heart disease. When sleep becomes too short or irregular, these systems struggle to operate effectively.

Research has also consistently linked chronic sleep deprivation with other metabolic disorders and overall cognitive decline, which leads to a shorter healthspan.

Modern life has disrupted natural sleep rhythms

Over the past half century, economic progress has reshaped the way societies function, and not always for the better. Global markets operate across time zones and digital devices allow work to continue long after sunset, with cities increasingly running twenty four hours a day.

These developments created remarkable economic opportunity, but they also disrupted circadian rhythms that evolved over thousands of years in response to natural light and darkness.

Research published in Nature Reviews Neuroscience shows that disruptions to circadian rhythms can affect metabolism, immune regulation and hormone balance.

Modern professional culture sometimes treats sleep as optional, yet the body continues to operate according to biological rules rather than workplace expectations. This is where circadian rhythms are at a disconnect with modern systems, which has disastrous effects on our collective health.

Singapore’s growing role in sleep awareness

Singapore, where I currently reside, provides an interesting lens through which to examine sleep health as part of preventive medicine. Rapid economic development has transformed the city-state into a global financial and technological hub, where demanding urban lifestyles can place pressure on healthy sleep habits.

At the same time, Singapore has played a notable role in the development of sleep medicine in Asia. The country’s first dedicated sleep laboratory was established in 1987 at Singapore General Hospital, where neurologists began studying sleep disorders using early polysomnography equipment. At the time, sleep medicine was still an emerging field globally, with relatively few specialist centres operating worldwide.

Local clinicians were among the first in the region to investigate obstructive sleep apnea (OSA), a condition in which breathing repeatedly stops during sleep and which is now recognised as a major public health concern linked to cardiovascular disease, metabolic disorders and cognitive decline. Early research in Singapore helped demonstrate that OSA was more common than previously assumed and highlighted its potential prevalence in Asian populations.

The formation of the Singapore Sleep Society in 2010 further strengthened research, education and public awareness efforts. Today, Singapore illustrates both the pressures modern urban life places on sleep, and the growing recognition of sleep health as a core component of preventive medicine and long-term wellbeing.

What World Sleep Day teaches us

Greater awareness of the gap between lifespan and healthspan has helped drive global interest in longevity and preventive health. The global longevity economy is now estimated to exceed USD 8 trillion, spanning biotechnology, diagnostics and preventive health.

Much of this innovation focuses on extending lifespan. Yet one of the most powerful ways to protect healthspan may lie in something far simpler: the quality of sleep we get each night.

World Sleep Day reminds us that long-term health depends not only on medical breakthroughs but also on respecting the biological rhythms that sustain the human body. Scientific progress will continue to push the boundaries of medicine, yet everyday habits remain powerful determinants of wellbeing.

Each night, the body quietly performs the work that allows us to age with strength, clarity and independence. In a world searching for the secrets of longevity, sleep may be one of the most powerful, and most overlooked, foundations of all.