Effects of sleeping positions on cardiac output and cardiac activity analyzing blood perfusion

In this work, the effects of different sleeping positions on cardiac output and cardiac activity are evaluated and a healthier sleeping position is recommended. Using different data acquisition units, the electrical bio-impedance based stroke volume is calculated in four different sleeping positions and hence cardiac output is evaluated. In addition, blood perfusion is measured by laser Doppler flowmetry technique in different sleeping positions to evaluate cardiac activity using frequency domain analysis. The stroke volume and hence the cardiac output is found maximum in soldier position for all subjects. Frequency domain analysis is also used to evaluate and compare cardiac activity with cardiac output in four different sleeping positions. Fast Fourier transform and power spectral density analysis show that the cardiac activity is highest at soldier position for most of the subjects. In addition, left sleeping position shows lowest cardiac output and cardiac activity. Since low blood perfusion and blood ejection is harmful for heart as well as human health, soldier sleeping position is highly recommended for all except the person with sleep disorders.