Rising temperatures are driving a surge in sleep apnea cases

Rising nighttime temperatures could quietly aggravate one of the world’s most widespread sleep disorders: obstructive sleep apnea (OSA). This could bring steep costs to public health and the global economy.

This warning comes from a new study by sleep researchers at Flinders University. The experts analyzed more than 58 million nights of sleep data and found a strong link between ambient temperature and breathing interruptions.

The results of the analysis suggest that, unless climate change is slowed, the worldwide burden of OSA may double before today’s newborns reach old age.

A billion people and counting

OSA already affects nearly a billion adults. People with the disorder repeatedly stop breathing during sleep as throat tissues collapse. This leads to drops in blood oxygen, loud snoring, and dozens or even hundreds of brief awakenings each night.

Untreated OSA is tied to hypertension, heart disease, cognitive decline, accidents, and depression. In Australia, the combined medical and productivity losses linked to poor sleep are estimated at roughly $66 billion per year.

Researchers knew little about how outdoor climate might influence the severity of the condition, despite its prevalence.

Bastien Lechat of the Flinders Health and Medical Research Institute (FHMRI) Sleep Health group is lead author of the study.

“This helps us to understand how environmental factors like climate might affect health by investigating whether ambient temperatures influence the severity of OSA,” said Lechat.

Linking sleep apnea to high temperatures

Lechat’s team partnered with a digital health company that provides a thin, FDA-cleared sensor placed under the mattress. The device measures subtle pressure changes to track breathing and body movement.

The researchers collected an average of 500 consecutive nights of raw data for each of 116,000 anonymous users in 29 mainly high-income countries. Altogether, this added up to more than 30,000 user-years of continuous monitoring.

The team then merged those sensor records with hourly surface-air temperatures generated by high-resolution climate models.

By comparing night-to-night shifts in breathing disruptions with local temperature fluctuations, the team could isolate the effect of heat from other confounding factors such as age, weight, or chronic illness.

“Overall, we were surprised by the magnitude of the association between ambient temperature and OSA severity,” Lechat said. When the overnight temperature rose, apnea severity followed.

“Higher temperatures were associated with a 45 percent increased likelihood of a sleeper experiencing OSA on a given night.”

Cooling technology may buffer heat stress

“These findings varied by region, with people in European countries seeing higher rates of OSA when temperatures rise than those in Australia and the United States, perhaps due to different rates of air conditioning usage,” Lechat said.

In other words, cooling technology – and the affluence that underwrites it – can buffer heat-related sleep stress, while people in older buildings or lower-income areas remain vulnerable.

The researchers translated these nightly risks into long-term stakes by running a health-economics model. They based it on disability-adjusted life years (DALYs), the same yardstick the World Health Organization uses to compare illnesses.

“Using our modeling, we can estimate how burdensome the increase in OSA prevalence due to rising temperature is to society in terms of well-being and economic loss,” Lechat noted.

The price of lost sleep

“The increase in OSA prevalence in 2023 due to global warming was associated with a loss of approximately 800,000 healthy life years across the 29 countries studied,” Lechat said.

“This number is similar to other medical conditions, such as bipolar disorder, Parkinson’s disease, or chronic kidney diseases.”

The team also attached a price tag. “Similarly, the estimated total economic cost associated was $98 billion, including $68 billion from well-being loss and $30 billion from workplace productivity loss,” Lechat said.

Those figures reflect only the added harm from climate change, not the baseline burden of OSA from other causes. Looking ahead, the numbers get starker.

According to Lechat, the findings highlight that without greater policy action to slow global warming, OSA burden may double by 2100 due to rising temperatures.”

Sleep study misses hot regions

Senior author Danny Eckert, a sleep scientist at Flinders, points out important caveats. Wealthier nations and individuals who can afford a modern sleep tracker dominate the data set.

“This may have biased our estimates and led to an underestimation of the true health and economic cost,” he said.

Many of the hottest, least air-conditioned regions – South Asia, Africa, parts of Latin America – are underrepresented, yet stand to experience the strongest warming trends.

Adapting sleep to hotter nights

Even as climate policy lags, the clinical community can act. “Higher rates of diagnosis and treatment will help us to manage and reduce the adverse health and productivity issues caused by climate-related OSA,” Eckert said.

Doctors still consider continuous positive airway pressure (CPAP) machines the gold-standard therapy. But alternative approaches – oral appliances, weight loss, and positional training – can also reduce breathing disturbances.

The next step for the researchers is to test protective strategies directly. “Going forward, we want to design intervention studies that explore strategies to reduce the impact of ambient temperatures on sleep apnea severity,” Eckert added.

For now, their message is clear: hotter nights are more than a comfort issue. They may be quietly robbing millions of restorative sleep, healthy years, and economic productivity – making climate mitigation, bedroom cooling, and sleep-health screening part of the same urgent conversation.

The study is published in the journal Nature Communications.

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