Effects of Ceiling Fans on Self-Reported Symptoms and Mood-State in Bed-Resting Older Adults Exposed to Indoor Overheating.

BACKGROUND

While fans are recommended for cooling at temperatures ≤ 40°C, the extent to which ceiling fans mitigate perceptual and physiological strain in older adults exposed to warm indoor environments (~31°C [87.8°F]) remains unclear.

METHODS

This follow-up analysis of our randomized study used validated questionnaires to evaluate effects of ceiling fans on self-reported heat-related symptoms (68-item Environmental Symptoms Questionnaire; ESQ-IV) and mood-state (40-item Profile of Mood States questionnaire; POMS-40) in bed-resting older adults during indoor overheating (8 h; 31°C (87.8°F), 45% relative humidity). Twenty participants (median age [interquartile range]: 71 [68-73] years; 12 females) completed two sessions with a ceiling fan set to 0 m/s (control) or ~1.5 m/s (fan). Perceptual outcomes (ESQ-IV, POMS-40) were assessed pre-exposure and at end heating. Cumulative physiological strain was assessed using area-under-the-curve (AUC) values for core temperature and heart rate over hours 0-8. End heating perceptual scores were evaluated using linear mixed-effects models adjusted for pre-exposure scores and fan condition (with/without each physiological strain index).

RESULTS

Core temperature and heart rate increased 0.15 [0.06, 0.24]°C (0.27 [0.11, 0.43]°F; p = 0.003), and 1.5 [0.5, 3.4] bpm (p = 0.135) per hour, respectively, with no-fan compared with fan use. After adjusting for core temperature AUC (p = 0.233), total symptom scores were 1.3-fold [1.1, 1.7] higher with no-fan (p = 0.015). Heart rate AUC did not modify this effect (p = 0.215); however, greater heart rate AUC was independently associated with higher symptom scores (p = 0.042). Mood disturbance did not differ between fan conditions and was not significantly associated with physiological strain markers (all p ≥ 0.187).

CONCLUSIONS

Ceiling fans alone do not fully mitigate perceptual or physiological strain in older adults exposed to prolonged indoor overheating. Nonetheless, a "fan-first" strategy integrating fan use with ambient cooling may offer an accessible, energy-efficient approach to enhance heat-health protection in this population.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT06142890.