Climate change has been shown to have a direct and indirect impact on many aspects of our life and our livelihood. Now a new study reveals it could also affect the quality of our sleep, especially among people living in urban areas. The importance of proper sleep, along with a healthy diet and regular exercise, is fundamental to a person’s overall health and wellbeing.
Researchers at Harvard Medical School in the United States found that both climate change and urban induced warming effects such as urban heat islands (UHI) can substantially increase nighttime temperatures and thereby impact the quality of sleep enjoyed by people. The study revealed that as nighttime temperature rises above 25 degrees centigrade, there is a rapid decline in quality of sleep.
An UHI is an urban area that is significantly warmer than its surrounding rural areas, with the difference being more perceptible at night than during the day, and most noticeable during summer and winter. The UHI effect could be caused by several factors, including reduced ventilation and heat trapping due to the close proximity of tall buildings, heat generated directly from human activities, the heat-absorbing properties of concrete and other urban building materials, as well as the limited amount of vegetation.
The elderly and those from lower socio-economic conditions are especially vulnerable to higher temperatures and its impact on quality sleep. In general, as we age,the depth of sleep and sleep duration are usually impaired, this is further exacerbated in elderly people with baseline medical conditions, mental health conditions, underlying sleep disorders, and those on medications..
Additionally, people with lower socioeconomic status are more likely to live in congested homes and in dense urban areas with less green space where the urban heat island effect is more intense. They also have less access to healthcare facilities to deal with consequences of disrupted and inadequate sleep.
For the study, participants wore sleep monitors and environmental sensors, which monitored the length of sleep, efficiency, and restlessness. Researchers gathered data from 50 older adults, which included 11,000 nights of sleep and environmental information. Findings revealed a 5 to 10 percent drop in sleep efficiency as temperature escalated from 25° to 30°C. As cities around the world get warmer this could impact sleep quality and overall health of people living in these areas,
During sleep, we fluctuate between phases where our body temperature is regulated differently. During the Rapid Eye Movement (REM) sleep — which makes up about a quarter of the time spent asleep — the body’s ability to regulate temperature is impaired. This means that if room temperature is high, the body is unable to adjust to it, which leads to frequent arousals from sleep.
Considering the effect of sleep deprivation on overall wellbeing of individuals, there is a rising need for healthcare officials and policy makers to tackle sleep disruptions caused by higher temperatures induced by climate change.