Older people have a reputation for being less impetuous. But when it comes to their investments, people at or close to retirement often react more precipitously to market downturns, according to financial advisors and researchers.

Older investors sold stocks more heavily during the market downturn of the 2007-09 recession, says David Blanchett, co-author of a paper on the subject. The same pattern showed up again this year as the market quickly lost a third of its value, said Blanchett, Morningstar’s head of retirement research.

“In theory, when the market drops, you actually want to get more aggressive because markets are cheaper,” Blanchett said. But older investors often do exactly the opposite. “If they sell after the market has gone down 10% or 20%, they end up taking a permanent loss.”

The urge of older investors to flee tumultuous markets is understandable. While younger workers know they won’t touch their 401(k) account for decades, many older Americans are already drawing them down.

But once money is pulled from a depleted portfolio, it may not be there when the market rebounds. Researchers call this sequence risk: when markets crater just as a retiree is beginning to spend savings. It’s a scary situation and can result in a meager retirement.

Investors shouldn’t try to address sequence risk in the midst of a market crash. Instead, they ought to plan for the next downturn and allocate less money to stocks if they are worried.

Robert Finley, a Chicago advisor, said every time he talks to clients, he asks them to consider what would happen to their portfolio if the stock market were to drop 50%.

“When I talk to clients before it happens, and I see them a little hesitant, I say, ‘Well, look if you can’t handle the theoretical discussion, once it happens in practice it’s going to be even more emotional,’” Finley said. “We definitely move them down the risk ladder. It’s a red light.”

When the market is volatile or sharply lower, advisors use various tactics to stop jittery clients from making impetuous decisions. Brian Fry, an Austin, Texas, advisor, said he ran computer simulations this spring for clients that showed their retirement plans were still on track despite market drops.

Jane Young, an advisor in Colorado Springs, Colo., said she makes sure her retired clients have enough money in a safe investment to cover five to seven years of distributions. When markets fall, she tells clients: “This is not going to affect you short-term.”

Some investors learned the value of riding it out in earlier downturns. Judi Mullins, a 60-year-old customer service manager for a Cincinnati manufacturer, sold some stocks in the 2008 market crash and regretted it. Even though she avoided big losses, she missed out on some of the market’s rebound after the recession.

So when the market plummeted this spring, Mullins said: “I just put it in the back of my mind.” Instead, she focused on her job.

Mullins, who plans to retire in five years, said she checked the balances on her investment accounts at the beginning of April and didn’t check them again until June.

“Now, I’m very happy,” she says. “Because they’re right back where they were.”

Indeed, now that markets are close to their pre-crash levels, some investors and advisors are selling stocks. “To take some risk off the table makes a lot of sense,” says financial advisor John Bovard of Cincinnati, whose clients include Mullins. In early June, Bovard said he dropped equity exposure for retirees and pre-retirees, including Mullins’ account, by 5% or 10%.

Some clients couldn’t wait for markets to calm down. Elyse Foster, a Boulder, Colo., financial advisor, manages $240 million in investments. But the money is kept in custodial accounts where customers still have access to it.

She and her staff came in one morning at the depth of the market crash and saw that one client had sold her entire $450,000 portfolio after hours. They contacted the client. “She said, ‘I panicked. I can’t handle this. I think the world is going to end,’ ” Foster said. The client is no longer with Foster’s firm.

financial advisor, the New Jersey advisor, had a tense talk during the downturn with a married couple in their late 60s. Their account was 50% stocks and 50% bonds, and the man wanted to sell everything. “The husband used the same language of fear and mentioned the Great Depression,” the financial advisor said.

In this case, the wife was confident that markets would bounce back, and she and the financial advisor convinced the husband to ride it out. They never sold, and their holdings have since rebounded.