The heat is on, and it's affecting your sleep. A recent study reveals that rising nighttime temperatures are linked to shorter and more disrupted sleep, especially for those with chronic health conditions, lower socioeconomic status, or residing on the West Coast. By 2099, people could lose up to 24 hours of sleep annually due to heat, according to the USC study. The findings, published in the journal Environment International, highlight the potential impact of climate change on sleep health.
Warm weather can disrupt sleep in various ways, including preventing the body from cooling down, triggering a stress response, and reducing deep sleep and REM sleep. Poor sleep, in turn, can increase the risk of heart and respiratory issues, as well as mental health concerns. As Jiawen Liao, PhD, notes, "We already know that during extreme heat events, more people die from cardiovascular disease and pulmonary disease. What will this mean for population health as global temperatures continue to rise?"
Past research has documented the link between rising temperatures and sleep problems, but most studies lacked detailed demographic, socioeconomic, and health information. This prevented researchers from understanding who is most at risk and how to respond effectively. The new study, conducted in collaboration with Harvard Medical School/Brigham and Women's Hospital and funded by the National Institutes of Health, utilizes data from 14,232 U.S. adults in the All of Us Research Program to address these gaps.
The researchers analyzed over 12 million nights of sleep data, examining sleep duration, ease of falling asleep, sleep stages, and interruptions. They also considered location and meteorological data to determine the impact of temperature changes on sleep patterns. The findings revealed that a 10-degree Celsius increase in nighttime temperature was associated with a 2.63-minute sleep loss, with greater effects among females, Hispanic individuals, those with chronic diseases, and those with lower socioeconomic status.
The study also found that the effects varied by season and geographic region. More sleep loss occurred from June to September, and people on the West Coast lost nearly three times as much sleep as those in other regions. Based on these findings, researchers project that U.S. adults could lose between 8.5 and 24 hours of sleep annually by 2099, depending on their location.
In addition to shorter sleep times, rising temperatures were associated with more disrupted sleep throughout the night and more time spent awake in bed. The study emphasizes that certain populations face higher risks, and targeting interventions and policy changes to these groups may be crucial. For instance, policymakers in West Coast regions could focus on improving access to air conditioning, expanding green roofs, and increasing urban green spaces. Strengthening building codes to enhance insulation, ventilation, and heat resistance could also protect population health.
Looking ahead, Liao and his colleagues plan to explore whether interventions like indoor cooling, green roofs, and sleep hygiene programs can mitigate the harmful effects of heat exposure. They aim to test whether improving sleep through these interventions can reduce heat-related health problems and lower the risk of disease and death.
