Researchers have found that the moving freight trains could disturb sleep and heart-rate of people not only due to the noise but also due to the vibrations.
This research has been published online in the journal PLoS ONE.
In this study, researchers worked on twelve participants in the age range of 20-29 years. They assessed the sleep disturbance and heart rate of the participants in a laboratory study. Sleep was assessed using questionnaires and heart rate was assessed using a combination of polysomnography and ECG recordings.
It has been found that “at high vibration amplitudes, but still within the range that can be encountered in the field, there was a reduction in sleep quality and higher sleep disturbance.” Michael Smith, from The Sahlgrenska Academy at the University of Gothenburg and the corresponding authors, told SayPeople.com.
In one of the previous studies, researchers found that increasing the vibration amplitude from 0.4 to 1.4 mm/s results in decreased sleep quality.
Furthermore, researchers have also found that the heart rate of the people could also be increased as a result of vibrations. They found that the combined effect of high vibration and noise condition is more in increasing the heart rate as compared to the effect of only noise.
The study is important as it has been estimated that the market share of the freight traffic would increase from 8% in 2001 to 15% in 2020. Freight trains are particularly important as they have heavier axle loads than passenger trains resulting in production of higher amplitude low frequency vibration.
World Health Organization (WHO) has already established the recommended levels of night time bedroom noise i.e. from 30dB to 45dB but there are no such recommendations related to the effect of vibration on the sleep, so this study is the first one to make us to consider the effect of low frequency components (of noise) along with vibrations on the sleep.
“As for future work, we are continuing our investigations into the effects of freight vibration and noise on sleep to try to gain a better understanding of how the body reacts, and what this might mean for people living nearby to railway lines.” Smith added.
Smith, M., Croy, I., Ögren, M., & Persson Waye, K. (2013). On the Influence of Freight Trains on Humans: A Laboratory Investigation of the Impact of Nocturnal Low Frequency Vibration and Noise on Sleep and Heart Rate PLoS ONE, 8 (2) DOI: 10.1371/journal.pone.0055829