New research reveals that maintaining a room temperature of 24 degrees or lower could significantly reduce sleep stress for older Australians. The study, conducted by researchers at Griffith University and published in the BMC Medicine journal, highlights the impact of temperature regulation during sleep on the body's stress response. Participants who slept in rooms with temperatures at or below 24 degrees Celsius exhibited lower heart rate variability (HRV) and reduced physiological stress. The study, which involved 47 individuals aged 65 and above, monitored their physiological status throughout the summer of December 2024 to March 2025. Researchers observed that as bedroom temperatures rose, stress responses increased, leading to less recovery during sleep. This finding suggests that temperatures above 24 degrees can trigger a 'fight or flight' response, impacting the body's ability to rest and recover. While there's no specific temperature threshold for immediate danger, the study indicates that stress levels tend to worsen with higher temperatures. Senior researcher Georgia Chaseling from the University of Sydney supports this, emphasizing the link between hot sleeping environments and changes in heart rate patterns. However, she clarifies that the study shows an association rather than a direct cause-and-effect relationship between hot weather and heart rate variability changes. Future research aims to strengthen the understanding of this connection by controlling for daily activity variations and expanding the sample group and climate areas. As Australia experiences a heatwave, with some regions expecting consecutive days of temperatures above 40 degrees Celsius, the study's findings take on added significance. Dr. O'Connor warns that prolonged exposure to high temperatures during sleep can lead to cumulative negative health effects, particularly during heatwaves, as individuals may struggle to recover adequately. The study recommends simple yet effective strategies to combat heat stress during sleep, such as using fans, wetting skin with spray bottles or towels, and taking cold showers before bed, especially when nighttime temperatures are below 35 degrees Celsius. These measures can significantly improve sleep quality and overall well-being. The absence of specific nighttime temperature guidelines by the World Health Organization prompts the need for further research to establish objective evidence for maximum night-time indoor temperatures, ensuring that older Australians can effectively manage stress and recover from daily heat exposure.
