Limits...
Vibration from freight trains fragments sleep: A polysomnographic study.

Smith MG, Croy I, Hammar O, Persson Waye K - Sci Rep (2016)

Bottom Line: Nocturnal trains in particular are of particular importance since night-time exposure may interfere with sleep.In an experimental polysomnographic laboratory study, 24 young healthy volunteers with normal hearing were exposed to simulated freight pass-bys with vibration amplitudes of 0.7 and 1.4 mm/s either 20 or 36 times during the night.Subjects reported sleep disturbance due to vibration (F(4,92) = 25.9, p < 0.001) and noise (F(4,92) = 25.9, p < 0.001), with the number of trains having an effect only for the 0.7 mm/s condition (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational and Environmental Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.

ABSTRACT
As the number of freight trains on railway networks increases, so does the potential for vibration exposure in dwellings nearby to freight railway lines. Nocturnal trains in particular are of particular importance since night-time exposure may interfere with sleep. The present work investigates the impact of vibration and noise from night-time freight trains on human sleep. In an experimental polysomnographic laboratory study, 24 young healthy volunteers with normal hearing were exposed to simulated freight pass-bys with vibration amplitudes of 0.7 and 1.4 mm/s either 20 or 36 times during the night. Stronger vibrations were associated with higher probabilities of event-related arousals and awakenings (p < 0.001), and sleep stage changes (p < 0.05). Sleep macrostructure was most affected in high vibration nights with 36 events, with increased wakefulness (p < 0.05), reduced continual slow wave sleep (p < 0.05), earlier awakenings (p < 0.05) and an overall increase in sleep stage changes (p < 0.05). Subjects reported sleep disturbance due to vibration (F(4,92) = 25.9, p < 0.001) and noise (F(4,92) = 25.9, p < 0.001), with the number of trains having an effect only for the 0.7 mm/s condition (p < 0.05). The findings show that combined vibration and noise from railway freight affects the natural rhythm of sleep, but extrapolation of significance for health outcomes should be approached with caution.

No MeSH data available.


Related in: MedlinePlus

Visual representation of train distribution in 36 event night (left) and 20 event night (centre).Acoustic characteristics of the auditory stimuli (right). LAEq,8h = 8 hour equivalent noise level. LAEq.pb = Pass-by noise level. LAF,max = Maximum noise level, fast time constant. t > 35 dB = pass-by duration. T10–90% = noise rise time. Noise levels are measured at the pillow position.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835753&req=5

f1: Visual representation of train distribution in 36 event night (left) and 20 event night (centre).Acoustic characteristics of the auditory stimuli (right). LAEq,8h = 8 hour equivalent noise level. LAEq.pb = Pass-by noise level. LAF,max = Maximum noise level, fast time constant. t > 35 dB = pass-by duration. T10–90% = noise rise time. Noise levels are measured at the pillow position.

Mentions: Exposure nights were constructed from a pool of 5 individual stimuli, the synthesis of which is described in detail elsewhere36 and only summarized here. Five audio recordings of freight train pass-bys were low-pass filtered to correspond to a closed window based on the curve of reference values for airborne sound as defined in ISO 717-1:199742. The characteristics of each train are presented in Fig. 1. The low frequencies (<125 Hz) of the train noise was introduced via eighty eight 10” loudspeakers concealed within the ceiling of each bedroom. The higher frequency components were reproduced by loudspeaker cabinets in two of the upper corners of each room. Noise and vibration exposure was introduced using a fully automated system from a separate control room. Since the background levels in the bedrooms were unnaturally low (<14dBA), band-pass filtered pink noise simulating ventilation noise was introduced throughout the trial at a level of 25 dBA measured at the pillow. Each stimulus was accompanied by vibration (rise time (0 mm/s to first peak) = 5.6 s). A 10 Hz sinusoid was amplitude modulated using c(t) given in equation (Equation 1). The modulation introduces sidebands around the main 10 Hz component from 8.3 to 11.7 Hz, but the secondary peaks are 15 to 25 dB lower than the carrier signal. The signal was generated after inspecting many indoor measurements and forming a repeating simple signal with the same time characteristics as a typical measurement3243. The shape of the waveform was verified by measurements on the frame of the bed used in the lab artificially loaded with weights of 75 kg. Amplitude A was adjusted such that the maximum root mean square (rms) Wd weighted acceleration44 was either 0.0204 ms−2 (“high”) or 0.0102 ms−2 (“moderate”). Perception thresholds are almost identical for recumbent persons along either the head-foot or side-side axis, only differing slightly at frequencies below 4 Hz and above 31.5 Hz45. The bed frame was therefore excited horizontally along the lengthwise axis36 by electrodynamic transducers (Quake Q10B, frequency response 5–40 Hz). Each shaker was driven separately by a 1000 W power amplifier (BKA1000-4A).


Vibration from freight trains fragments sleep: A polysomnographic study.

Smith MG, Croy I, Hammar O, Persson Waye K - Sci Rep (2016)

Visual representation of train distribution in 36 event night (left) and 20 event night (centre).Acoustic characteristics of the auditory stimuli (right). LAEq,8h = 8 hour equivalent noise level. LAEq.pb = Pass-by noise level. LAF,max = Maximum noise level, fast time constant. t > 35 dB = pass-by duration. T10–90% = noise rise time. Noise levels are measured at the pillow position.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835753&req=5

f1: Visual representation of train distribution in 36 event night (left) and 20 event night (centre).Acoustic characteristics of the auditory stimuli (right). LAEq,8h = 8 hour equivalent noise level. LAEq.pb = Pass-by noise level. LAF,max = Maximum noise level, fast time constant. t > 35 dB = pass-by duration. T10–90% = noise rise time. Noise levels are measured at the pillow position.
Mentions: Exposure nights were constructed from a pool of 5 individual stimuli, the synthesis of which is described in detail elsewhere36 and only summarized here. Five audio recordings of freight train pass-bys were low-pass filtered to correspond to a closed window based on the curve of reference values for airborne sound as defined in ISO 717-1:199742. The characteristics of each train are presented in Fig. 1. The low frequencies (<125 Hz) of the train noise was introduced via eighty eight 10” loudspeakers concealed within the ceiling of each bedroom. The higher frequency components were reproduced by loudspeaker cabinets in two of the upper corners of each room. Noise and vibration exposure was introduced using a fully automated system from a separate control room. Since the background levels in the bedrooms were unnaturally low (<14dBA), band-pass filtered pink noise simulating ventilation noise was introduced throughout the trial at a level of 25 dBA measured at the pillow. Each stimulus was accompanied by vibration (rise time (0 mm/s to first peak) = 5.6 s). A 10 Hz sinusoid was amplitude modulated using c(t) given in equation (Equation 1). The modulation introduces sidebands around the main 10 Hz component from 8.3 to 11.7 Hz, but the secondary peaks are 15 to 25 dB lower than the carrier signal. The signal was generated after inspecting many indoor measurements and forming a repeating simple signal with the same time characteristics as a typical measurement3243. The shape of the waveform was verified by measurements on the frame of the bed used in the lab artificially loaded with weights of 75 kg. Amplitude A was adjusted such that the maximum root mean square (rms) Wd weighted acceleration44 was either 0.0204 ms−2 (“high”) or 0.0102 ms−2 (“moderate”). Perception thresholds are almost identical for recumbent persons along either the head-foot or side-side axis, only differing slightly at frequencies below 4 Hz and above 31.5 Hz45. The bed frame was therefore excited horizontally along the lengthwise axis36 by electrodynamic transducers (Quake Q10B, frequency response 5–40 Hz). Each shaker was driven separately by a 1000 W power amplifier (BKA1000-4A).

Bottom Line: Nocturnal trains in particular are of particular importance since night-time exposure may interfere with sleep.In an experimental polysomnographic laboratory study, 24 young healthy volunteers with normal hearing were exposed to simulated freight pass-bys with vibration amplitudes of 0.7 and 1.4 mm/s either 20 or 36 times during the night.Subjects reported sleep disturbance due to vibration (F(4,92) = 25.9, p < 0.001) and noise (F(4,92) = 25.9, p < 0.001), with the number of trains having an effect only for the 0.7 mm/s condition (p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational and Environmental Medicine, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.

ABSTRACT
As the number of freight trains on railway networks increases, so does the potential for vibration exposure in dwellings nearby to freight railway lines. Nocturnal trains in particular are of particular importance since night-time exposure may interfere with sleep. The present work investigates the impact of vibration and noise from night-time freight trains on human sleep. In an experimental polysomnographic laboratory study, 24 young healthy volunteers with normal hearing were exposed to simulated freight pass-bys with vibration amplitudes of 0.7 and 1.4 mm/s either 20 or 36 times during the night. Stronger vibrations were associated with higher probabilities of event-related arousals and awakenings (p < 0.001), and sleep stage changes (p < 0.05). Sleep macrostructure was most affected in high vibration nights with 36 events, with increased wakefulness (p < 0.05), reduced continual slow wave sleep (p < 0.05), earlier awakenings (p < 0.05) and an overall increase in sleep stage changes (p < 0.05). Subjects reported sleep disturbance due to vibration (F(4,92) = 25.9, p < 0.001) and noise (F(4,92) = 25.9, p < 0.001), with the number of trains having an effect only for the 0.7 mm/s condition (p < 0.05). The findings show that combined vibration and noise from railway freight affects the natural rhythm of sleep, but extrapolation of significance for health outcomes should be approached with caution.

No MeSH data available.


Related in: MedlinePlus