As Australia braces for another scorching summer, new research led by Flinders University sleep experts reveals that rising temperatures are silently chipping away at our sleep and with it, our health.
Published in a major international study, the findings show that warmer nights are causing widespread reductions in sleep duration across the globe.
Analysing over 165 million nights of sleep data from more than 317,000 users of wearable and under-mattress sleep tracking devices, researchers found that when temperatures rise from the global median of 12°C to 27°C, people lose an average of 15 to 17 minutes of sleep.
More concerning, the likelihood of experiencing short sleep-defined as less than six hours per night-increases by approximately 40% with similar results being observed during heatwaves.
"Sleep is essential for physical and mental health, and our findings show that high temperatures are quietly undermining this fundamental biological need," says lead author and sleep expert, Dr Bastien Lechat, from FHMRI Sleep Health.
"This isn't just about our comfort, it's about our cognition, mood, immune function, and long-term overall wellbeing."
The findings are part of a large scale research project led by Flinders University exploring the impact of rising temperatures and changing environmental conditions and how they affect sleep health to help project the long-term consequences of a progressively warming climate.
Co-first author and biostatistician Barbara Toson says the study used validated consumer sleep tracking devices and controlled for environmental factors such as humidity, air pollution, and cloud cover.
"This is one of the most comprehensive analyses of sleep and climate to date," she says.
"We've shown that the relationship between temperature and sleep is robust across devices, regions, and demographics and clearly shows that heat induced sleep loss is impacting people of all ages and health backgrounds."
Senior researcher on the paper, Professor Danny Eckert, says that the implications are far-reaching.
"Sleep deprivation is linked to depression, cardiovascular disease, impaired cognitive function, and increased risk of accidents," says Professor Eckert.
"As global temperatures continue to rise, the burden of sleep-related health issues is likely to grow too."
Dr Lechat says that there are ways to adapt and protect sleep in warmer times.
"Urban design, housing, and public health strategies such as using heat-resilient housing designs and urban cooling strategies, such as green roofs, tree planting, and reflective building materials could help," he says.
"We can also take steps to safeguard our own sleep, such as keeping bedrooms cool with fans, air conditioning or breathable bedding, which can help your body rest.
"Closing blinds and sunny-side windows during the day to block heat, and opening them at night if there is a late cool breeze can also protect bedrooms from heating up.
"Drinking water regularly and avoiding caffeine to stay hydrated helps your body regulate temperature and sleep better, and avoiding heavy meals and alcohol before bed can help to reduce sleep disruption."
The article, 'How do we sleep while our beds are burning? High ambient temperatures are associated with substantial sleep loss', by Bastien Lechat, Barbara Toson, Hannah Scott, Duc Phuc Nguyen, Billingsley Kaambwa, Amy C Reynolds, Jack Manners, Robert Adams, Jean-Louis Pepin (Univ. Grenoble Alpes, France) Sebastien Bailly (Univ. Grenoble Alpes, France), Andrew J K Phillips, Pierre Escourrou (Centre Interdisciplinaire du Sommeil, France), Peter Catcheside and Danny J Eckert was published in SLEEP. DOI: 10.1093/sleep/zsaf323
See also: https://news.flinders.edu.au/blog/2025/06/17/climate-change-linked-to-dangerous-sleep-apnea/
Acknowledgments: Dr Lechat and Professor Eckert are supported by National Health and Medical Research Council (NHMRC) of Australia Fellowships.
