NEW YORK (CNNMoney.com) - When gasoline prices jump, consumers and retailers start feeling the pain.

And with gasoline nearing record highs in recent weeks, retail analysts warn that it's low-income consumers who will feel the pinch first.

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Where do they shop? At super-discount chains like Dollar General (Research) and Dollar Tree (Research) and the big discounters Wal-Mart (Research) and Target (Research).

Piper Jaffray analyst Mitch Kaiser wrote in a recent research note that over the past five years he's observed that when gas prices rise, retail sales take a hit.

And the companies that got hit the hardest over that period, with the biggest declines in sales at stores open at least a year, were Wal-Mart and Dollar General.

Higher gasoline prices pressure a retailer's sales in two ways, Kaiser noted. First, cash-strapped consumers cut back on trips to the store. Then they also spend less on each trip since they're forced to pay more to fill up the tank.

"For companies in our coverage universe, we would [now] take a cautious approach toward the comparable sales of Big Lots, and 99 Cents Only Stores," Kaiser said in his note.

Wal-Mart, the world's largest retailer, averages more than 100 million shoppers a week to its stores. But despite that impressive traffic, the retailer's core shoppers are low-income consumers, many of whom live paycheck-to-paycheck.

Speaking at a Wal-Mart media conference earlier this month, CEO Lee Scott indicated that he was a "little bit concerned" that high gas prices could dampen sales this year.

Wal-Mart has every reason to be very worried, said Marshal Cohen, chief industry analyst with market research firm NPD Group.

"When gas prices go up 5 cents a gallon, that's maybe an extra $10 a week out of consumers' pockets. But when they're going up 15 cents and more, it means $20 extra a week," Cohen said.

Some people can cope by skipping a cup of Starbucks coffee or a movie. But the recent increases have been so dramatic that they'll probably take an even bigger bite out of discretionary spending.

"Last year consumers on average spent $500 more for the year on gas. This year it could go up to $1,000. This is what Lee Scott is worried about," Cohen said. "The average American has $2,400 in discretionary spending. A Wal-Mart shopper probably has $1,500. Now take out the $1,000 extra and what does that leave them?"

If gas prices don't retreat, Cohen said, he'd be worried about retail sales for the rest of the year, and possibly even during the holiday shopping season, which typically accounts for as much as 50 percent of retailers' annual profits and sales.

Further, any long-term pullback in consumer spending doesn't bode well for the broader economy since consumer purchases fuel two-thirds of the economy.

"We're not there yet but it's not too soon to assume this scenario," said Cohen.

The tipping point is $4 a gallon. At those levels, the issue takes on both an economic and political dimension and it's almost certain that the government would intervene quickly to ensure that prices retreat. That happened last year when gas prices spiked to an all-time record of $3.06 a gallon in the aftermath of Hurricane Katrina and the Bush administration took measures to ease the pressure on consumers by releasing supplies from the Strategic Petroleum Reserve.

Just this week, President Bush announced steps to address the current gas price squeeze, including a curb of tax breaks for oil companies, investigation into gouging, and halting deposits to stockpile.

Besides discounters and dollar stores, the negative impact of higher gas prices could percolate to other types of retailers the longer that consumers have to keep paying more for a gallon.

Teenagers are always immediately affected by gas price changes since many depend on their cars for getting to their jobs. "The less money they have, the less they'll spend in malls and teen stores like Hot Topic and Abercrombie & Fitch," Cohen said.

And if moderate-income shoppers cut back, that could hut sales at department stores, restaurants, furniture stores and clothing chains, analysts said.

"The segment most impacted has been the family dining chains such as Cracker Barrel Old Country Store, Bob Evans Farms and Ryan's due to the proximity of their locations to highways and their reliance on lower- and middle-income consumers, who have been disproportionately affected," analysts at S&P Equity Research said in a note this week.

People tend to dine out less when gas prices rise, but quick-service chains like McDonald's (Research) and Burger King can actually benefit as consumers cut back from casual restaurant chains to fast food.

At the same time, food suppliers will probably incur higher transportation costs that they'll pass along to restaurant operators in the form of surcharges.

What does this mean for consumers? If restaurant chains can't keep absorbing the costs, it could very well translate to higher food prices down the road, said Cohen. "This is also true for other retailers. At some point, businesses will have to pass on some of the higher costs to customers."

But high-end retailers like Nordstrom (Research) and Saks are less susceptible to gas prices since their customers spend far less on energy than lower-income households. Therefore, their sales should hold up, Goldman Sachs analyst Matthew Fassler, wrote in a note Wednesday.

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