Effects of ceiling fan use on cardiovascular autonomic function during simulated indoor overheating in bed-resting older adults
Abstract
Older adults are at heightened susceptibility to heat-related cardiovascular complications when exposed to indoor overheating. While ceiling fans are recommended as an accessible cooling intervention, their effects on cardiac autonomic regulation remain unclear. In this randomized crossover study, 20 healthy older adults (median age 71 years, 12 female) completed two 8-h exposures to simulated indoor overheating (31°C, 45% relative humidity) while bed-resting with either no fan (control) or ceiling fan use (∼1.5 m/s airflow). Core temperature and heart rate were monitored. Before exposure and between hours 6 and 7, participants underwent cardiac autonomic response testing including measures of heart rate variability (SDNN, RMSSD - indices of overall and parasympathetic/vagal cardiac autonomic modulation, respectively) and supine-to-standing tests (30:15 ratio, systolic blood pressure response) as well as self-reported symptoms of orthostatic intolerance. Ceiling fan use reduced peak core temperature (0.2°C [95% CI: 0.1-0.3]; P < 0.001), heart rate (-5 beats/min [-10 to 0]; P = 0.03), and attenuated heat-induced reductions in RMSSD (4.7 ms [0.2-9.2]; P = 0.04) compared to control. However, fan use did not influence SDNN, blood pressure during postural changes, cardiac response to standing, or symptoms of orthostatic intolerance. While ceiling fans provided modest reductions in core temperature and heart rate and partially preserved RMSSD, they offered limited overall…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 20 participants or records.
Read the paper
Related studies
- Metformin as an adjuvant in breast cancer treatment
- Metformin Lysosomal Targeting: A Novel Aspect to Be Investigated for Metformin Repurposing in Neurodegenerative Diseases?
- Aberrant HSF1 signaling activation underlies metformin amelioration of myocardial infarction in mice
- Metformin induces ZFP36 by mTORC1 inhibition in cervical cancer-derived cell lines
- Protein Interaction Network for Identifying Vascular Response of Metformin (Oral Antidiabetic)
- Preventing Long COVID With Metformin
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.