Stocks went on a wild ride Tuesday, with the Dow (Dow Jones Global Indexes: .DJI) swinging more than 300 points, and legendary investor Jack Bogle told CNBC that investors should brace themselves for more turbulence and perhaps a significant decline ahead.
But while people should get used to a volatile market, there is one thing they should certainly not do, he said.
"If you're going to jump in and out of anything on a moment's notice, you will be badly defeated. That's a speculative strategy," Bogle, founder of The Vangard Group, said in an interview with " Closing Bell ."
"Times of great market turbulence ... are just awful times to make investment decisions."
Instead, investors should have a long-term investment strategy and stay the course, he said.
As for where to invest, Bogle advises sticking with U.S. stocks over international equities.
While foreign stocks may be cheaper, they are riskier, he said. Plus, U.S. companies are really international companies, since half their profits come from outside the country.
"I'd rather bet on the U.S.," he said. "This is a great nation with great places to invest. Great financial institutions, great government institutions, although a little bit faltering."
For those who do want to add international exposure to their portfolio, he wouldn't invest more than 20 percent.