Expose yourself to natural daylight (even on overcast days) for 10 to 30 minutes upon waking, without sunglasses, to stimulate the morning cortisol peak in order to improve energy, mood, sleep, and stress resistance.

noli's read

The importance of morning light in regulating our biological clock is solidly demonstrated by research in chronobiology. Laboratory studies, such as the one by Figueiro and Rea (2012, controlled clinical trial), confirm that exposure to morning light supports the cortisol awakening response (CAR). This cortisol peak is a natural physiological phenomenon that increases by an average of 50% after waking, as documented by Pruessner and his colleagues (1997, cohort study). However, presenting outdoor light as the direct cause of this 50% boost is slightly exaggerated: this peak is primarily an endogenous process triggered by waking, which light serves to calibrate and amplify. Furthermore, the claim that this routine prepares the body for faster and lower-amplitude stress reactions remains a theoretical extrapolation, without a strong scientific consensus. Conversely, the advice to go outside even in cloudy weather is excellent, as the outdoor light intensity (in lux) remains significantly higher than that of our interiors for effectively stimulating our ocular receptors.

the sources

1. 1Blume C, Garbazza C, Spitschan M 2019
2. 2Brown TM et al. 2022