Actually 20% is dwarfed by other interventions. "Swedish study demonstrated that over a 20- year period, women who avoided the sun were TWICE AS LIKELY TO DIE OF ANY CAUSE, as women who were sun-seekers" referring to:
Lindqvist PG, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort.
J Intern Med. 2016 Oct;280(4):375-87
Lindqvist PG, Epstein E, Landin-Olsson M, Ingvar C, Nielsen K, Stenbeck M, Olsson H. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86
Stress and MCAS often do correlate with photosensitivity, and if you have MCAS all your allergy-like reactions are going to be increased by stress, true. I've found that if my exposure to sunlight is very regular I do pretty well, though. Of course, if stress leads you to take tricyclics, they can cause photosensitivity as well. I would not discount the possibility that regular sun exposure reduces stress by boosting the immune system (not just by Vitamin D) however:
https://www.labroots.com/trending/health-and-medicine/4846/b...
Lindqvist PG, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. 2016 Oct;280(4):375-87
Lindqvist PG, Epstein E, Landin-Olsson M, Ingvar C, Nielsen K, Stenbeck M, Olsson H. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86