Sleep is one facet of our health that is impacted by climate change. Sleep is vital for restoring physical and mental health. Sleep deprivation speeds up the aging process and can lead to various cardiometabolic disorders. Not getting enough good sleep used to be seen as a lifestyle problem, but it is now considered as a distinct disease. The current terminology for sleep deprivation is “insufficient sleep syndrome” (ISS). While ISS can be deliberate and self-induced, environmental cues are also a risk factor.
One of the ways the body prepares itself to fall asleep is by cooling the body. Before falling asleep, temperature at the body’s distal sites, like the hands and feet, increases slightly. This increase causes the core body temperature to drop. The body’s temperature remains low while asleep, then increases again before awakening.
When the environmental or room temperature is warmer than usual, it’s more difficult for the body to decrease its temperature for sleep onset and maintain the lower temperature during sleep. That’s why it’s harder to fall and stay asleep in warmer temperatures. Because climate change is causing higher temperatures in many parts of the world, people may have a more difficult time getting good sleep.
In the United States, the average temperature has increased 0.8-1.0 ᵒC since 1895. The rise has been steeper since 1970. Rising temperatures have caused more heat-related events. Higher daytime temperatures are leading to persistently higher nighttime temperatures.
There is evidence that negative effects of higher temperatures are stronger in elderly and lower income populations. The most vulnerable people for climate-sensitive diseases are those least responsible for such a climate crisis.
The climate crisis can reduce sleep in other ways, such as air pollution. Recent studies show that air pollution can lead to obstructive sleep apnea (OSA). In OSA, there is reduced or blocked airflow to the lungs during sleep. This leads to reduced oxygen saturation in blood. The brain wakes up repeatedly to choking episodes during sleep. OSA impairs sleep quality and daytime functioning and can lead to premature death.
EXTREME WEATHER EVENTS
The climate crisis is responsible for more cyclones and extreme weather events. Since the middle of the 20th century, the frequency of very severe cyclonic storms has increased significantly. These events have negative effects on acute and chronic sleep health due to loss of shelter, anxiety, and posttraumatic stress disorders.
Climate changes will lead to more climate refugees. A 2018 World Bank Group report estimated that the impacts of climate change in Sub-Saharan Africa, South Asia, and Latin America could lead to more than 140 million people leaving their homes before 2050. This has a tremendous effect on mental health. Such adverse mental health conditions will cause more sleep problems in the affected population. Sleep problems and mental health have a bidirectional relationship and perpetuate each other.
The five pillars of good health are good food, good water, good air, good sleep, and regular exercise. The first four components are directly affected by climate changes. Though much attention has been shown regarding food, water, and air safety, there has been little concern about sleep health. The right to a healthy sleep environment is still a concept in need of attention. Sleep problems are not yet included in lists of climate-sensitive diseases. Given sleep’s importance to maintain a healthy body and mind, it cannot be ignored.
Dr Arup Haldar works for the Department of Pulmonary Medicine, Woodlands Multispecialty Hospital, in Kolkata, India. He completed a fellowship in Epidemiology and Biostatistics and has worked in sleep medicine for 17 years. He has a special interest in obstructive sleep apnea and titration methodologies.
Alcayna T, Fletcher I, Gibb R, et al. Climate-sensitive disease outbreaks in the aftermath of extreme climatic events: A scoping review. One Earth. 2022;5(4): 336-350 doi: https://doi.org/10.1016/j.oneear.2022.03.011
Chattu VK, Sakhamuri SM, Kumar R, Spence DW, BaHammam AS, Pandi-Perumal SR. Insufficient Sleep Syndrome: Is it time to classify it as a major noncommunicable disease? Sleep Sci. 2018;11(2): 56-64. doi: 10.5935/1984-0063.20180013.
Obradovich N, Migliorini R, Mednick SC, Fowler JH. Nighttime temperature and human sleep loss in a changing climate. Sci Adv. 2017;3(5):e1601555. doi: 10.1126/sciadv.1601555.
Rifkin DI, Long MW, Perry MJ. Climate change and sleep: A systematic review of the literature and conceptual framework. Sleep Medicine Reviews. 2018;42(Dec):3-9. doi: https://doi.org/10.1016/j.smrv.2018.07.007.
Mendelsohn R, Emanuel K, Chonabayashi , et al. The impact of climate change on global tropical cyclone damage. Nature Clim Change. 2012;2:205–209. doi: https://doi.org/10.1038/nclimate1357
Ahmed B. Who takes responsibility for the climate refugees? International Journal of Climate Change Strategies and Management. 2018;10(1):5-26. doi: https://doi.org/10.1108/IJCCSM-10-2016-0149