My annual physicals always include a blood test, though I now realize I have no idea what it is they are testing for. My doctor just tells me the blood work was normal. I take a multivitamin each day and just looked to see what it says. It says D rather than D2 or D3 so who knows what it is exactly. Yet another thing I know nothing about. I do get outside year round though. In the winter it is just my face exposed of course when I go for walks or am shoveling snow. Once it hits 50 in the spring I shift to shorts and teeshirts until it no longer hits 50 in the autumn so there’s a bit more skin exposed but I’m not one to lounge around pools in a bathing suit or work outside shirtless. I get chastised enough for being less than diligent with sunscreen without going shirtless too. Short sleeve teeshirts come out when it starts to hit 60.