Dale Carnegie said you can use a strategy based on stock trading to be less anxious

One of the worst parts about being an anxious person is that your anxiety often seems to have a life of its own.

Once you start worrying about something, it appears there's nothing left to do except ride the wave of your emotions until it breaks.

But what if, with a little advance planning, you could give yourself an exit strategy - a way to disembark from the wave?

Enter Dale Carnegie, the bestselling author of "How to Win Friends and Influence People," originally published in 1936. Carnegie also authored "How to Stop Worrying and Start Living" in 1948, in which he outlined a series of techniques for combatting everyday anxieties.

One of those techniques is based on a strategy used in stock trading, and it was developed by an investment counselor named Charles Roberts. It involves placing "stop-loss orders" on your investments.

Roberts told Carnegie that he learned the stop-loss principle from a speculator named Burton S. Castles.

Here's how it works: Every time you buy a stock, you immediately set a stop-loss order on it. For example, if you buy a stock for $50 a share, you might set the stop-loss order at $45. That means that as soon as the share price hits $45, you automatically sell the stock, no questions asked.

"By limiting your losses to five points," Castles reportedly told Roberts, "you can be wrong more than half the time and still make plenty of money."

Eventually, Roberts realized that the stop-loss principle - deciding in advance how much of your resources you're willing to sink into a project or effort - could apply in domains outside of finance, and could in fact apply to "every kind of annoyance and resentment" as well.

Carnegie gives an example of how he used the stop-loss strategy in his own life, even before he labeled it that way. At one point, he'd dreamed of becoming a novelist and in fact spent two years in Europe toiling away on his masterpiece. Unfortunately, the manuscript was rejected by every publisher he approached.

Carnegie says he felt trapped, uncertain whether to continue pursuing his dream or move onto something else.

Ultimately, he writes, "I wrote off my two years of sweating over that novel for just what they were worth - a noble experiment - and went forward from there." He resumed writing nonfiction works and teaching adult education classes, and presumably never gave another thought to novel-writing.

(Of course, Carnegie didn't exactly use the stop-loss strategy because he only decided in hindsight that two years was his limit, but it's a similar idea.)

Even Abraham Lincoln used a version of the stop-loss strategy. According to Carnegie, Lincoln wouldn't hold grudges against people that had wronged him in the past, simply because it wasn't worth the energy.

"A man doesn't have time to spend half his life in quarrels," Lincoln reportedly said. "If any man ceases to attack me, I never remember the past against him."

The general idea behind the stop-loss strategy is to determine how much things are worth to you, and how much psychological turmoil you're willing to endure for their sake.

Chances are the answer won't be "an infinite amount." You'll probably be able to come up with a maximum amount of time and energy that you're willing to invest before moving on.

Ultimately, reframing your anxieties as drains on your resources, instead of human-like entities that must be catered to, puts you back in control of your life.