A common myth about aging says that after 50, people (especially women) face a dreary life of loneliness, physical difficulty, and despair.

But the opposite is true for millions, who are finding that the "grandma years" are turning out to be the best time of their lives.

Adults 65 to 79 say this is their happiest stage of life, according to a British study of 300,000 people. The study found that satisfaction with life peaked during this period. This jibes with other clinical and anecdotal research in the United States, which has more women over 50 than ever before, according to the US Census Bureau.

It isn't hard to see why women at this stage of life report such levels of satisfaction.

They are often more able to focus on their own wellbeing than during their child-raising years. They are trending toward retirement and less work-related stress. And many say they no longer feel the anxiety about money and keeping up with peers that drove them earlier in life.

Fitness plays a huge role in helping people this age feel satisfied, healthy and confident. That's because fitness gives mature people the ability to continue living the way they want to live -- to enjoy hobbies, travel, sports, grandchildren and other things they value. It gives them the stamina and agility to avoid injury and hospitalization.

And let's face it: If you feel good physically, you're going to be happier.

So, come on: Let’s get happy!