Key result
Exposure to secondhand smoke-related PM2.5 significantly decreased heart rate variability, including a 46.9% reduction in RMSSD and a 77.7% reduction in HF power over 240-minute moving averages.
Why the study?
Does exposure to secondhand smoke-related PM2.5 reduce heart rate variability in non-smoking adults?
Observational (n=35)
Single-blind
No
Does exposure to secondhand smoke-related PM2.5 reduce heart rate variability in non-smoking adults?
Effect estimate: 46.9% decrease in RMSSD
p-value: p=<0.01
Short- and longer-term exposure to secondhand smoke-related PM2.5 is associated with significant decreases in heart rate variability, indicating acute adverse autonomic and cardiovascular effects.
May indicate acute autonomic effects from secondhand smoke; hypothesis-generating and leaves open clinical relevance in Level 5 data.
PURPOSE: Exposure to secondhand smoke (SHS) has been associated with decreased heart rate variability (HRV). However, the time course of this association is unclear. Therefore, the objective of this study was to investigate the association between 15-240 minute SHS-related fine particulate matter (PM2.5) moving averages and indices of HRV. METHODS: With a panel study design, we used personal monitors to continuously measure PM2.5 and HRV of 35 participants who were exposed to SHS for approximately 6 hours. RESULTS: We observed negative, significant associations between 5-minute HRV indices and 15 minute PM2.5 moving averages and 240 minute PM2.5 moving averages: there was a significant (p<0.01) 7.5% decrease in the 5-minute square root of the mean squared differences of successive normal heart beats associated with (RMSSD), and a significant (p<0.01) 14.7% decrease in the 5-minute high frequency (HF) power associated with the 15 minute PM2.5 moving averages; there was also a significant (p<0.01) 46.9% decrease in the 5-minute RMSSD, and a significant (p<0.01) 77.7% decrease in the 5-minute high frequency (HF) power associated with the 240 minute PM2.5 moving averages. CONCLUSIONS: Our findings that exposure to SHS related PM2.5 was associated with HRV support the hypothesis that SHS can affect the cardiovascular system. The negative associations reported between short and longer term PM2.5 and HRV indicate adverse effects of SHS on the cardiovascular system.
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Garza et al. (2016) conducted an observational in Healthy non-smokers (n=35). Secondhand smoke PM2.5 exposure vs. Unexposed or lower exposure periods was evaluated on 5-minute heart rate variability (HRV) indices (RMSSD and HF power) (46.9% decrease in RMSSD, p=<0.01). Exposure to secondhand smoke-related PM2.5 significantly decreased heart rate variability, including a 46.9% reduction in RMSSD and a 77.7% reduction in HF power over 240-minute moving averages.
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