While for many, fall is a time of joy and wonder at the blazing colors and abundance of late harvest, for others, it is a time of low morale and loss of energy.
Indeed, it seems that many people, especially those living in the northern hemisphere (like us!), are prone each year to experience symptoms related to the change of season, mainly caused by the decrease in the number of hours of daily sunlight as well as by the late sunrise in winter.
This decrease in exposure to natural light disrupts our internal biological clock, thus influencing the normal course of our sleep and wake cycles and the secretion of various hormones and neurotransmitters.
Among the best known are serotonin, involved in mood regulation, and melatonin, a hormone secreted by the pineal gland at dusk to promote a state conducive to sleep - among others.
To try to counteract the deleterious impacts that the decrease in natural light can have on our biological rhythms, it is possible to put strategies in place.
Maximize your sunshine
Try to take advantage of the sunshine as much as possible by encouraging outdoor physical activity, such as walking, running or skiing in winter. It will be possible to expose arms and legs naked, with good warm socks, gloves, a sleeveless jacket, a hat and a scarf. Pants can also be pulled up to the knees and sleeves to the elbows at the slightest opportunity.
Three hours per week of exposure, which can be broken down into quarter hours or half hours, is ideal. Vitamin D synthesis occurs even on overcast days, whereas the effects will be nil when exposed behind glass! (1)
Minimize blue light
Since the circadian system is extremely sensitive to the blue wavelengths emitted by the artificial lights of electronic screens and fluorescent lights, it would be appropriate to pay special attention to limiting exposure to blue light.
Some applications exist to simulate the decrease in natural light on screens, giving them a yellow-orange color that does not alter melatonin production.
Daily exposure to this type of blue light, especially if it occurs in the evening, is associated with a delay in the onset of melatonin. This phase shift in the secretion of this hormone could thus probably explain the difficulty in finding sleep in the evening, and the greater sleepiness on waking experienced by those affected. (2)
To counteract these effects, it is also possible to count on the help of light therapy which, through the use of specially adapted lamps, can be a tool specially adapted to simulate the effect of natural light.
Certain types of lamps are designed to act as a dawn simulator upon awakening, slowly increasing in intensity to initiate a gentle awakening. This option may be appropriate for people who work a night shift or have difficulty getting up at the crack of dawn each morning.
Studies have shown beneficial physiological effects by resynchronizing the biological clock (circadian system), by improving alertness, by acting on sleep regulation and on serotonin secretion. (3)
There is a wide variety of lamps on the market today, to suit all tastes depending on the criteria sought (portability, size). In all cases, they should provide a light intensity ranging from 2000 to 10,000 lux. As a comparison, a candle emits an intensity of about 1 lux; inside a building (at the office, for example) the luminosity is estimated at 300 lux; while on a sunny day on a beach, this intensity is close to 100,000 lux.
In order to obtain beneficial effects, light therapy should ideally be used daily upon awakening, with an intensity of 10,000 lux for 30 minutes, or 5,000 lux for 1 hour or 2,500 lux for 2 hours. (1)
In any case, do not hesitate to discuss it with your naturopath for advice, or with a doctor in case of more marked depressive symptoms.
Have a good season!
(1) CHOUKROUN, Jérémy et GEOFFROY, Pierre Alexis. Light Therapy in Mood Disorders: A Brief History with Physiological Insights. 2019.
(2) DUPONT, Caitlin. THE ROLE OF ENVIRONMENTAL LIGHT EXPOSURE AND CIRCADIAN TIMING IN SEASONAL AFFECTIVE DISORDER. 2019. Thèse de doctorat. University of Pittsburgh.
(3) MARUANI, Julia et GEOFFROY, Pierre Alexis. Bright light as a personalized precision treatment of mood disorders. Frontiers in Psychiatry, 2019, vol. 10, p. 85.