Omanghana
A new global study has found that rising nighttime temperatures linked to climate change are significantly reducing the amount of sleep people get each year, with the average person losing nearly 56 hours of sleep annually due to increasingly warmer nights.
The analysis, conducted by the nonprofit research organization Climate Central, examined temperature trends across 1,338 major cities worldwide and found that nights are warming faster than days in many parts of the world. The researchers warn that this growing trend is making it harder for millions of people to achieve the deep, restorative sleep essential for maintaining good physical and mental health.
According to the study, the annual sleep deficit is equivalent to losing approximately seven full nights of sleep every year.
Warmer Nights Are Disrupting Natural Sleep Cycles
Unlike daytime heat, elevated nighttime temperatures interfere directly with the body’s natural cooling process.
Human body temperature normally drops during the evening to help initiate and maintain deep sleep. However, when overnight temperatures remain unusually high, the body struggles to cool itself, making it more difficult to fall asleep, stay asleep, and reach restorative stages of sleep.
Researchers found that this effect has become increasingly common as global temperatures continue to rise.
Climate Change Responsible for Growing Sleep Loss
The report concludes that a measurable portion of annual sleep disruption can be directly attributed to human-induced climate change.
On average, researchers estimate that around six hours of sleep lost each year are specifically linked to global warming caused by greenhouse gas emissions.
The study notes that this climate-related sleep loss has more than doubled since the 1970s, reflecting the accelerating pace of global temperature increases over recent decades.
Scientists warn that unless greenhouse gas emissions are significantly reduced, warmer nights are expected to become even more frequent, increasing the burden on public health worldwide.
Sleep Problems Increase Above Key Temperature Threshold
Researchers identified a critical temperature threshold where sleep disruption becomes much more severe.
When overnight temperatures remain above 20°C (68°F), the body’s ability to regulate its internal temperature declines, increasing the likelihood of restless sleep, repeated awakenings, and shorter sleep duration.
As heatwaves become more frequent and intense, many cities are experiencing longer periods where nighttime temperatures remain above this threshold.
Tropical Regions Face the Greatest Impact
The study found that sleep loss is not evenly distributed around the world.
Countries in tropical and arid climates experience the greatest burden because they already endure consistently warm nights, leaving residents with little opportunity to cool down after sunset.
Among the hardest-hit regions are:
- Southeast Asia
- The Middle East
- West Africa
- Parts of Central and South America
In some of these areas, researchers estimate that residents lose more than 80 hours of sleep each year due to excessive nighttime heat.
Rapid urbanization has further intensified the problem in many cities through the urban heat island effect, where buildings, roads, and concrete surfaces absorb heat during the day and release it slowly overnight, keeping cities significantly warmer than surrounding rural areas.
Older Adults and Women More Vulnerable
The report highlights several groups that are particularly vulnerable to heat-related sleep disruption.
Adults aged 65 years and older are among those most affected because aging reduces the body’s ability to regulate temperature efficiently.
Women also experience greater sleep disruption during periods of high nighttime heat, although researchers say further studies are needed to better understand the biological and environmental factors contributing to this disparity.
People living in lower-income countries are also disproportionately affected, as many lack access to air conditioning, reliable electricity, or housing designed to reduce indoor temperatures.
Health Risks Extend Beyond Fatigue
Experts warn that chronic sleep deprivation caused by rising temperatures can have far-reaching consequences beyond simply feeling tired.
Long-term sleep loss has been associated with an increased risk of:
- Cardiovascular disease
- High blood pressure
- Diabetes
- Weakened immune function
- Depression and anxiety
- Reduced cognitive performance and concentration
- Workplace accidents and lower productivity
Poor sleep can also impair memory, decision-making, and emotional well-being, affecting both individual health and broader economic productivity.
Climate Change Becoming a Public Health Challenge
Health experts say the findings add to growing evidence that climate change is increasingly becoming a major public health issue.
While much attention has focused on extreme heat, flooding, droughts, and severe storms, researchers argue that the effects of warmer nights on sleep represent a less visible but equally important consequence of global warming.
They emphasize that improving urban planning, increasing green spaces, expanding access to cooling technologies, and reducing greenhouse gas emissions will be essential to protecting public health as global temperatures continue to rise.
As climate change drives more frequent and intense heat events around the world, scientists warn that safeguarding healthy sleep may become an increasingly important part of adapting to a warming planet.
Source: Omanghana
