Warmer nights are costing people sleep

Because nights are warming with climate change, more people are having a harder time falling and staying asleep. Unless there is adaptation or a reduction in greenhouse-gas emissions, people won’t sleep enough for two weeks each year due to high temperatures, on average, globally. Adaptation is especially important in the Pacific Northwest, where air conditioning is less common. 

In a Q&A, Dr. Molly Billings, professor of pulmonary, critical care and sleep medicine at the University of Washington School of Medicine, discusses how heat undermines sleep. She offers recommendations for mitigating those effects. The conversation has been edited for length and clarity. 

Q: Why is sleep important? 

A: Sleep is vital for life. When you sleep, you process memories and restore your brain function by clearing toxins. Your heart rate and blood pressure go down, and your endocrine system resets. 

Q: How does heat impact sleep? 

A: Studies have shown people sleep fewer hours and have more disrupted sleep when it’s hot. I've definitely seen this in my patients. Those who live in homes without air conditioning sleep especially poorly. They can be bothered by noise and air pollution because they have their windows open instead. 

Q: Are there disparities in how heat affects sleep? 

A: There definitely are disparities in terms of heat experience. There are heat islands within cities. Areas with less tree canopy, typically lower-income residential areas, tend to be hotter. People in those areas often don't have access to air conditioning and may have worse quality sleep when it is hot. 

Q: How can people improve their sleep when temperatures are high? 

A: For individuals, do the best you can to keep your sleeping space cool. Close the blinds during the day. Use a fan at night, which can also protect you from noise. In the summer, avoid getting too much light late in the day and exercising late in the day because they make it less likely you're going to fall asleep. Other things to do are to cool off before bed and do something to wind down. Taking a shower can help some people relax and cool off. 

Q: What policy changes could help? 

A: On a policy level, we need to improve our infrastructure to have more equitable living environments. Planting trees and enhancing green space to reduce urban heat is one step. We also need more support for programs that provide air conditioning to low-income people.

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