Bedroom design orientation and sleep electroencephalography signals

Background: Orientation is a significant factor in architectural design that may affect well-being. Body direction does not change during sleeping, and sleeping is sensitive and affected by environmental factors. Aims: This neuroarchitecture study aimed to assess the effects of bed orientation on sleep quality to enhance bedroom design. Materials and Methods: To do so, the effects of earth's electromagnetic field (EMF) on sleep electroencephalography (EEG) signals were evaluated using signal processing techniques. In this cross-sectional study, a total of 21 healthy volunteer participants slept for two consecutive naps, at two rooms with identical interior design and different bed orientations, toward and against earth's EMF in a sleep clinic. Statistical Analysis: In this experiment, discrete wavelet transform extracted five subfrequencies of EEG data as delta, theta, alpha, beta1, and beta2. In addition, the energy signals were computed by measurement of wave frequencies. The mean total sleep time was 1.63 h in North–South (N-S) earth's EMF orientation and 1.38 h in the other direction. Results: t-test results showed significant changes in delta, theta, and alpha frequencies in terms of bed orientation. There was a significant result in the alpha energy ratio over the whole signal energy. Furthermore, there were increases in the average energy of delta, theta, and alpha bands in N-S versus East–West (E-W) bed directions. Conclusions: This study indicated that sleep in N-S direction could be more beneficial than E-W and the sleep EEG signals can be sensitive to earth's EMF. The results show the importance of considering orientation in bedroom design and its benefits on inhabitants' well-being.