Seasonal Variation in Sleep, Respiratory, and Cardiovascular Parameters Assessed by a Wearable Device

Area of Science:

• Sleep Science
• Respiratory Physiology
• Wearable Technology

Background:

• Seasonal variations in sleep are known, but their impact on sleep architecture and respiratory function using wearable tech is understudied.
• Environmental factors like light and temperature may influence sleep quality and apnea severity.
• Large-scale, real-world data on seasonal sleep modulation are limited.

Purpose of the Study:

• To investigate the seasonal impact on sleep architecture and respiratory physiology using wearable home sleep studies.
• To analyze how environmental factors across seasons affect sleep parameters and apnea severity.
• To examine age-related modifications in seasonal sleep and respiratory patterns.

Main Methods:

• Retrospective analysis of 2,386 home sleep studies using the SleepImage wearable system (2022-2025).
• Studies categorized by season (winter, spring, summer, fall).
• Statistical analysis (ANCOVA, multiple linear regression) adjusted for age to assess main and interaction effects (Season × Age).

Main Results:

• Significant seasonal differences observed in sleep latency, apnea-hypopnea indices (AHI), oxygen saturation (SpO₂), and heart rate after age adjustment.
• Sleep latency was longest in summer and shortest in fall (p < 0.001).
• Apnea-hypopnea indices were highest in winter, lowest in fall (p = 0.027); mean SpO₂ was reduced in colder months (p < 0.001).
• Mean heart rate was higher in winter than summer (p < 0.001).
• Age modified seasonal effects: older adults had greater winter sleep latency increases but smaller seasonal apnea fluctuations.

Conclusions:

• Sleep and respiratory parameters show distinct seasonal modulation.
• Winter is associated with increased apnea burden and reduced oxygenation.
• Summer is linked to prolonged sleep latency and fragmented sleep.
• Age plays a role in how individuals experience seasonal changes in sleep and respiratory health.