Bengaluru Residents Lose 67 Hours of Sleep Per Year as Night Temperatures Rise

Bengaluru residents lost an average of 67 hours of sleep per year between 2020 and 2025 due to rising nighttime temperatures, making it the worst-affected metro city by climate change in India. The findings were revealed in an analysis by Climate Central, an independent international group of scientists.

According to the study, climate change added approximately 16 extra nights per year in Bengaluru between 2018 and 2023 where summer temperatures remained above 20 degrees Celsius. Out of the 67 hours of annual sleep loss recorded between 2020 and 2025, eight hours—or 12 percent—were directly attributed to climate change.

To estimate the impact on sleep, Climate Central scientists compared observed temperatures to counterfactual temperatures, which represent what the climate would have been without carbon pollution. They analyzed data from 2020 to 2025 and compared it to a historical period in the early 1970s.

The report highlighted that warmer nighttime temperatures lead to shorter sleep duration and reduced sleep quality. These effects are particularly strong during the hottest periods, in warmer regions, and among vulnerable populations.

Local healthcare experts stated that sleep is essential for physical and mental well-being, helping the body recover, strengthening the immune system, supporting heart health, and improving concentration. A healthcare expert noted that as Bengaluru becomes warmer, the body struggles to cool down, a process vital for falling and staying asleep. The expert added that even small sleep losses can build up over time, affecting overall health, productivity, and quality of life.

While climate change is a major driver, experts also pointed to rapid urbanization in Bengaluru as a key factor. The city is steadily losing its green cover and open spaces to concrete buildings, roads, and other impervious surfaces. These structures absorb heat during the day and release it slowly after sunset, keeping nights warmer through the urban heat island effect.

Although Bengaluru is the worst-affected metro in India, the analysis showed that other cities in Karnataka experienced even greater sleep loss. Residents of Kalaburagi lost an average of 80 hours of sleep each year, followed by Hubballi at 71 hours, and Mysuru at 70 hours.