Exposure to bright light (10,000 lx) or extreme darkness (<0.01 lx) significantly increased the LF/HF ratio compared to dim light (100 lx) in young healthy subjects.
Observational
Does exposure to different light intensities and sleep stages affect heart rate variability in young healthy subjects?
Both extreme light conditions and different sleep stages significantly alter autonomic nervous system balance as measured by heart rate variability.
Effects of light intensity and sleep stages on heart rate variability (HRV) were investigated in young healthy subjects. The low-frequency (LF)/high-frequency (HF) ratio was significantly increased by exposing either to bright lights of 10 000 lx or to extreme darkness (< 0.01 lx), while HF and LF components of HRV were not changed, when compared with those under dim light (100 lx). However, LF was significantly increased at REM sleep, when compared with that at the pre-sleep wake. In contrast, HF was increased at all stages of sleep, and the LF/HF ratio was decreased at slow wave sleep during the baseline night.
Tsunoda et al. (Fri,) conducted a observational in Healthy. Light intensity (bright light or extreme darkness) and sleep stages vs. Dim light (100 lx) and pre-sleep wake was evaluated on Heart rate variability (LF/HF ratio, LF, and HF components). Exposure to bright light (10,000 lx) or extreme darkness (<0.01 lx) significantly increased the LF/HF ratio compared to dim light (100 lx) in young healthy subjects.