(HealthDay News) – For adults, individual daytime noise exposure correlates with changes in heart rate variability, with effects less pronounced for noises of 65 dB(A) or more, according to a study published online March 19 in Environmental Health Perspectives.

Ute Kraus, MPH, from Helmholtz Zentrum München in Neuherberg, Germany, and colleagues examined the correlation between individual daytime noise exposure and heart rate variability in a prospective panel study involving 110 individuals participating in 326 electrocardiogram recordings with a mean duration of six hours. A-weighted equivalent continuous sound pressure levels (Leq) were used to measure individual noise exposure.

The researchers found that concurrent increases of 5 dB(A) in Leq up to 65 dB(A) correlated with significant increases in heart rate and in the ratio of low-frequency to high-frequency power, and with decreases in low-frequency and high-frequency power. There was a positive association between standard deviation of normal-to-normal intervals with concurrent noise up to 65 dB(A), and a negative association for noise lagged by five to 15 minutes. For noise ≥65 dB(A), associations with cardiac function were less pronounced, with some associations being in opposite directions from those with noise of up to 65 dB(A). Sex and age modified concurrent associations.

“Individual daytime noise exposure was associated with immediate changes in heart rate variability, suggesting a possible mechanism linking noise to cardiovascular risk,” the authors write. “Noise at lower levels may have health consequences beyond those resulting from ‘fight-or-flight’ responses to high levels of noise.”

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