Is light at night darkening your mood?
A study in Japan linked an increase in depressive symptoms to low-light exposure at night. The study involved 863 seniors, none of whom had any signs of depression. The researchers investigated levels of light exposure at night by using light meters. Participants were then followed for two years during which time 73 developed symptoms of depression.
On investigation the researchers observed that those who felt depressed were exposed to 5-lux or more of light at night. This roughly equates to around the amount of light you’d get from a television that’s on in a darkened room. On the other hand, participants who slept in completely dark rooms were less likely to develop signs of depression than those who were exposed to more light at night. While this study observed the older generation, with an average age of 71, the effects of light at night are thought to be even greater on younger people who have more sensitive eyes. This means that the younger generations could be more vulnerable to the way lighting can influence our mood.
Let there be light! How does light exposure affect our mood?
So, how does light work to influence our mood? Well, the researchers who took part in the study theorise that light at night could affect the body’s internal clock and interfere with the secretion of melatonin. This, in turn, is then thought to have negative consequences for our mood although this particular study was not designed to investigate cause and effect. There are a number of other ways though that light is thought to influence our mood…
Increasing intensity of emotions
One study found that bright light has the ability to make us feel warmer by increasing the intensity of our emotions. The study, published in the Journal of Consumer Psychology, found that the more intense the lighting, the more intensely we felt emotions – both positive and negative! The researchers found that, although the temperature of the room was kept the same, feelings of warmth increased when the brightness of the lighting increased.
In other experiments carried out, researchers investigated different lighting conditions and asked participants to rate a person’s attractiveness, feelings towards positive and negative words and the spiciness of a sauce. In brighter lighting conditions participants were found to experience more intense emotions – they observed the person as being more attractive, positive words yielded more positive responses, negative words yielded more negative responses, and they preferred spicier sauces.
Natural light can make us happier and prevent SAD
Natural sunlight increases our serotonin levels which can contribute to our overall happiness levels. Also known as Seasonal Affective Disorder or seasonal depression, SAD is largely affected by light exposure. Symptoms of SAD are most likely to occur in the darker, winter months where daylight hours become shorter and our light availability is at its minimum. In fact, light is so important to our mood, light therapy and specialised SAD lamps are even available to help treat symptoms of SAD and depression.
It can affect our appetite
Yep, light can even affect our appetite! Have you ever noticed that certain restaurants use a particular style of lightening? Well, that’s no accident! Green, yellow, orange and blue lighting are thought to stimulate feelings of hunger whilst darker greys and browns help to curb your hunger.
It can affect our sleep cycles
The disruptive effect of blue light from electronic devices on our sleeping patterns is well known. The blue light that these devices emit keep us alert and focused, essentially tricking our brain and body into believing that it is still daytime. When we struggle to get good quality sleep our mood is by no means unaffected. If we are sleep deprived we can experience difficulty focusing, irritability, low mood, as well as the inevitable tiredness.
Herbs to help lift your mood
When it comes to lifting low mood I always suggest Hyperiforce tablets. These tablets contain extracts of the herb St John’s Wort which has a long standing traditional use of helping to relieve low mood. Hyperiforce is a licensed traditional herbal remedy that is made from organically cultivated, freshly harvested St John’s Wort.
1 Kenji Obayashi et al, “Bedroom Light Exposure at Night and the Incidence of Depressive Symptoms: A Longitudinal Study of the HEIJO-KYO Cohort.” American Journal of Epidemiology, March 1, 2018, doi.org/10.1093/aje/kwx290
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