Being deficient in vitamin D puts you in a category that has almost double the risk of death relative to normal levels. However, supplementation with vitamin D has not shown greater longevity. We know that low vitamin D levels come with the usual suspects (obesity, sedentary behavior).
Interesting discussion. E.g. If you have these conditions in mid-life: overweight, pre-diabetes, elevated blood pressure, then it puts you at greater risk for cognitive decline later in life. Waist line of 52 inches in men or 45 inches in women doubles your risk of mortality.
People who have coronary heart disease live longer if they get on a cardiac rehab exercise program. The greater the level of fitness they are able to achieve and the more they work out, the longer they live.
The aggregate research done to date suggests when doctors do "multifactorial lifestyle interventions" (i.e., trying to get patients to eat and exercise better), their patients' risk of dying from heart disease is reduced by 18%.
2 interesting findings in this small study: (1) that exercise added weight loss to those eating a calorie-restricted diet, and (2) splitting up exercise into three daily ~13 minute bouts caused 3X the weight loss at 12 weeks, than doing 40 minutes of exercise all at once. This suggests that we might be best served to "exercise as you are, whenever you can" rather than the monolithic trip to the gym.