A man who spent 5 years studying rich people found they dedicate 30 minutes to one - free - pastime every day

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President Obama works out for 45 minutes a day, six days a week.

For the purposes of his study, "rich people" are as having an annual income of $160,000 or more and a liquid net worth of $3.2 million or more.

In his research, he noticed a pastime the wealthy have in common: They exercise consistently.

"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."

Aerobic exercise includes anything that incorporates cardio, such as running, jogging, walking, or biking.

"Cardio is not only good for the body, but it's good for the brain," he writes. "Daily aerobic exercise feeds the brain, cleans the brain, and increases your intelligence, each and every time you engage in it."

Wealthy people value their health, says Corley. In addition to exercising, they watch what they eat, sleep seven or more hours every night, and avoid drinking too much alcohol and watching too much TV.

One individual in Corley's study was 68, worth nearly $80 million, and was still working. "I asked why he didn't retire, and he looked at me like I was from Mars," Corley reports. "He said, 'I've spent the last 45 years exercising every single day and watching what I eat because I knew the end of my career would be my biggest earning years.' If he can extend his career four to five years beyond everyone else, that's about $7 million for him."

Science backs Corley's findings.

Numerous studies show that exercise is one of the most important habits you can develop to transform your life. Working out can boost your memory, concentration, and mental sharpness - and you don't need to spend a lot of time, or money, doing it to reap the benefits.

Need inspiration? Read about the exercise habits of President Barack Obama, Richard Branson, and 13 other highly successful people.