Zero fitness? You have the most to gain

If you're more like Mara than Michael, you can significantly reduce your mortality risk by simply going from no activity to some activity. Pause for a 15-minute daily walk at an easy pace. Build up to 20 minutes and walk faster, and you'll lower your risk even more.

Getting to a healthy weight is still one of the most important goals you can set for yourself. It can help you avoid or control conditions such as diabetes, high blood pressure, joint problems and even pregnancy complications.

But if your goal is living well and living long, work on improving your cardiovascular fitness. In fact, unless you're an elite athlete at peak fitness, you'll gain health benefits every time you add distance, time or intensity to your daily activities.