“Seventy-six percent of the rich aerobically exercise 30 minutes or more every day,” Corley reports in his book, “Change Your Habits, Change Your Life.” It helps in numerous ways, since “cardio is not only good for the body, but it’s good for the brain.”

But don’t just take his word for it. Billionaires Mark Zuckerberg, Richard Branson and Mark Cuban all agree that exercise has played a role in their success.

“I seriously doubt that I would have been as successful in my career (and happy in my personal life) if I hadn’t always placed importance on my health and fitness,” says Branson, who wakes up at 5:00 a.m. every morning to play tennis, bike or kite-surf.

Plus, exercise, he claims, boosts his productivity significantly: “I definitely can achieve twice as much by keeping fit,” Branson tells FourHourBodyPress.

Zuckerberg also knocks out his workout right away. “I make sure I work out at least three times a week — usually first thing when I wake up,” says the Facebook founder in a Q&A. “Staying in shape is very important. Doing anything well requires energy, and you just have a lot more energy when you’re fit.”

Ultimately, if you make health and happiness a priority, says Branson, “the rest will follow.”

Don’t miss: How Mark Cuban, Richard Branson, and 34 other top execs stay in shape