Jack Bogle — legendary investor and entrepreneur — had his first heart attack at 31, when doctors discovered he had a congenital heart condition called right ventricular dysplasia. For most of his working years, he suffered arrhythmias that would sometimes cause him to collapse. Eventually, at 65, the founder of the world's largest mutual fund company, $4 trillion Vanguard, needed a heart transplant.

From his health travails, Bogle learned many life lessons about success.

"I think you could be defeated by something like (a heart condition)," he said at a recent event at Jefferson Hospital in Philadelphia. "But all these little things are interruptions in the routine of life that one should not take really seriously." Instead, he suggests that you stick to the routine you've set for yourself, no matter what. It's that routine of work that will take you where you want to go.

Bogle went back to growing Vanguard, which he said now has more than $4 trillion in assets. He stepped down as CEO when he received the transplant but has turned to writing books and speaking as an investor advocate.

He also delivered five other nuggets of wisdom for young people, with a nod to the tumultuous economy and difficult job market they face. Millennials are the only generation out of the four current generations who don't identify work ethic as a key part of their identity, according to the Pew Research Center. Many want to eschew the corporate world entirely and start their own business to take charge of their destiny.

Here's Bogle's advice to a generation facing unique challenges.

1. If you're going to be an entrepreneur, have a stomach for risk. "Being an entrepreneur is not for the faint of heart. It is a high-risk, high-reward proposition. While we would typically encourage young people to start saving for the future as early as possible, it's unlikely that a budding entrepreneur will be able to do so," he said by email. "The entrepreneur will need every bit of capital available for the business, which will likely crowd out personal savings. This may not be prudent in the traditional sense, but it is necessary. The entrepreneur's business can be thought of as a highly risky, concentrated stock position. If it doesn't work out, you can be wiped out. But if it does work, the rewards can be "beyond the dreams of avarice."