Lighting the home environment for circadian health

Occupational therapy practitioners (OTPs) have long embraced the importance of lighting for visual performance and safety in the home, particularly for older adults (Perlmutter et al., 2013). The discovery of a novel photoreceptor, the intrinsically sensitive retinal ganglion cells (ipRGCs), demonstrated that light also impacts overall health by entraining our body’s circadian rhythms. Poor circadian entrainment undermines complex body functions including sleep, digestion, glucose metabolism, healing, and filtering toxins from the brain—among others (Foster, 2021). Decades of research indicate that regular bright light exposure in the morning is the most potent external cue to set our internal circadian rhythms. When circadian rhythms are entrained, our body cycles work in tandem and occur at about the same time every day or night (Figueiro, et al., 2018).