Why go outside

Sunlight & Vitamin D

The oldest, free-est supplement there is.

Most of what your body gets from vitamin D doesn't come from food — it comes from your skin, reacting to sunlight. It's one of the simplest biological processes you can trigger just by stepping outside.

How it actually works

When UVB rays hit your skin, a cholesterol compound just beneath the surface converts into vitamin D3, which your liver and kidneys then turn into the active form your body uses. No pills, no food — just 10–30 minutes of midday sun on bare skin, a few times a week, is generally enough for most people to produce a meaningful dose. Darker skin tones and higher latitudes typically need somewhat longer exposure.

Why it matters

Bones — vitamin D is essential for calcium absorption; without it, bones can become soft or brittle over time.
Immune function — it plays a regulatory role in how your immune system responds to pathogens.
Muscle function — low levels are associated with muscle weakness and fatigue.

Because modern life happens mostly indoors and under artificial light — which doesn't produce vitamin D — a large share of adults get less sun exposure than their bodies are built for.

"Where the sun does not go, the doctor does." — Italian proverb

Let Outside keep score

You don't need to remember to go outside, or track it by hand. Outside runs quietly in the background and logs your time in the sun automatically — just carry your phone like normal and let it do the counting.

GET IT ONGoogle Play