[Fraaaank]

I should've been more specific. The study you link states that 'To prevent vitamin D deficiency, one should spend 15 to 20 minutes daily in the sunshine with 40% of the skin surface exposed.'. The screenshot on lume health shows a goal of 120 minutes.

Moreover, sun exposure is not by definition 'healthy'. Spending two hours in the sun at noon in the middle of summer does more harm than good.

[agensaequivocum]

> Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking.

https://pubmed.ncbi.nlm.nih.gov/26992108/

[brokegrammer]

The study seems to be incredibly flawed.

> Women with active sun exposure habits were mainly at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death

Not surprised there because people who spend more time outdoors will typically be participating in physical activity at the same time, while people who avoid sun exposure will typically be seated while participating in sedentary activities.

If we want to see if sun exposure is the sole reason for longevity, we will have to force the subjects to sit on a couch outside.

Claiming that not getting sunlight is the same as smoking is pure garbage.

[tvier]

> Claiming that not getting sunlight is the same as smoking is pure garbage.

So you're throwing out a whole study because it didn't cover a specific confounding variable you thought of, than stating a claim with no evidence backing it up?

That's pure garbage.

They specifically call this out in the abstract.

> We obtained detailed information at baseline on their sun exposure habits and potential confounders.

https://pubmed.ncbi.nlm.nih.gov/24697969/

[adolph]

> The study you link states that 'To prevent vitamin D deficiency, one should spend 15 to 20 minutes daily in the sunshine with 40% of the skin surface exposed.'. The screenshot on lume health shows a goal of 120 minutes.

Linearly it follows that if one wears clothes that cover more than 40% of lit skin, then the duration would be adjusted to match the total skin-area/time.

If one start with 1.85 m^2 body surface area, 40% of that is .72 m^2. If clothing covers 50% of a human and the human's shape and hair occludes half of that remaining, you have .46 m^2 available for sunlight. .72 m^2 * 20 is 14.4 m^2/min. divided by .46 m^2 it seems that 31.3 min would be the daily amount.

This seems much less than lume health's goal of 120 min. Otoh, given there is less opportunity for get to 14.4 m^2/min daily (I'm looking outside at a nice rainstorm), maybe the 120 min has some catchup factor?

[porridgeraisin]

Yes, you get your sun in the morning and/or in the evening. This is standard.

[agensaequivocum]

Morning and evening sun are excellent due to the high levels of Near-IR and IR. However, it is devoid of UVB needed for vitamin D synthesis. You need morning, evening, and midday sun.