As temperatures hit 26 degrees across the UK this week, millions are set to experience a familiar pang of guilt when they opt to remain indoors.
It’s often presumed that this is because the UK is accustomed to greyer skies; however, this is not true. Here, Mike Kocsis at Balance My Hormones reveals the 5 science-backed reasons behind sunshine guilt phenomenon.
The “Sunshine Hormone” Circuit
Research in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry reveals that the readiness of the brain’s D2/D3 dopamine receptor is higher in people who experience high sun exposure than those who don’t. This indicates that the dopaminergic system is sensitive to our exposure to the sun and creates its own unique circuit.
The function of the ‘sunshine dopamine circuit’ is why we feel so rewarded when we step out into the sunshine. When high sun exposure is detected but avoided, the circuit doesn’t receive the stimulation it was expecting, which sparks the feeling of ‘sunshine guilt’.
Vitamin D…opamine
The ‘sunshine vitamin’, D, is produced when the skin absorbs sunlight. Vitamin D is synonymous with happiness as it produces the feel-good hormone serotonin. The body has evolved to depend on the sunshine and vitamin D pathway, and if we interrupt it by staying indoors, our brain interprets it as a warning signal, which in turn, stirs a feeling of guilt.
Light a Neurotransmitter Release
Research conducted at Ohio State University Centre states that when exposed to outdoor light, specialised retinal cells assist in regulating pupil dilation, allowing it to admit light. These cells are linked to others that release dopamine, a crucial neurotransmitter in the eye and brain.
When we fail to activate this pathway due to insufficient natural light, our bodies detect the lack of anticipated neurotransmitter signals, leading to feelings of dissonance that we perceive as guilt.
Circadian Rhythm Regulation and Hormonal Balance
The body’s mechanisms align with natural light cycles. Research published in the Journal of Clinical Endocrinology & Metabolism indicates that exposure to natural daylight regulates circadian rhythms, slows melatonin production, and activates cortisol release.
Staying indoors on sunny days interrupts our natural light-driven cycles, leading our hormonal systems to note this change. As a result, we emotionally perceive this disruption as guilt.
UV-Induced Endorphin Release
Research from the University of Edinburgh found that UV exposure causes the skin to release endorphin-like molecules that create feelings of pleasure and reward. This evolved pathway ensures humans seek sufficient sunlight for optimum health.
When we avoid sunshine, the body misses its natural high, leading to what researchers define as “heliogen reward deprivation”—essentially withdrawal symptoms from sunshine that manifest partly as guilt.
To receive the maximum benefits of sun exposure, we should head out into the sun as soon as possible after waking for at least 15 minutes. Not only will this lead to a notable uplift in mood, but it also improves fatigue, the immune system and sleep hygiene.
