The Christmas shopping season begins in earnest today and more than ever, shoppers will be very closely watched -- not only by retailers, but also by a wide array of business executives and economists who are looking for clues on the economy's strength.

With consumer debt at an all-time high and personal savings at a record low, there is mounting concern that consumer spending, the steam that has been driving the economy for the past three years, will cool off soon.

"Consumers are tired out," said Stacy Ruchlamer, a retailing specialist for Shearson Lehman Bros. Inc. Pointing to the debt figures, she added, "Consumers will be buying presents, but they will not go overboard."

Retailers -- ever fearful of the Christmas Grinch -- are concerned that the slowdown may come in the next six weeks.

"It will be touch and go," said Edwin Hoffman, chairman of Woodward & Lothrop Inc. It's not just the high level of consumer debt that has Hoffman worried.

He, like other retailers, is also concerned about the six fewer shopping days between now and Christmas, owing to Thanksgiving's late arrival on the calendar this year. Last year, Thanksgiving was on Nov. 22.

"We have a bad calendar break and the warm weather hasn't helped," he said. "We will have an increase in sales, and a profitable year, but it will be tight."

Complicating matters, Hoffman said, is the Maryland savings-and-loan crisis.

With thousands of consumers unable to withdraw any of their money from three state-insured S&L's and tens of thousands more limited to only $1,000 withdrawals at 11 other S&L's, Hoffman expects sales in Maryland to be adversely affected.

"There is nothing you can put your finger on, but you know [the problem] is out there," he said.

For consumers, the retailers' growing concerns means a steady parade of special sales, especially as it gets closer and closer to Christmas.

However, the discounts may not be as deep or as plentiful as last year when retailers overstocked their shelves in anticipation of a bell-ringing Christmas.

More cautious this time around, most retailers have carefully limited their purchases and planned their sales around items they have bought at special discounts.

As a result, even though many retailers may step up the pace of their sales to get people into their stores earlier in the season, they say they do not expect price cuts as drastic as last year when they found themselves desperate to push many of their goods out of the stores.

Their cautious handling of merchandise is aimed at maintaining acceptable profits even if sales volume is less than great.

Consequently, retailers warn shoppers that if they are seeking some of the most popular goods this season, they better shop early.

Among the more popular items this year are: the Pound Puppy, a plush stuffed animal complete with dog tag applications, some of the more sophisticated video-cassette recorders, compact disc players, rechargeable kitchen appliances and an ice-cream maker that doesn't need electricity or salt.

"Our inventories are 10 percent below where they were last year," commented Robert E. Brewer, K mart Corp.'s executive vice president. "The consumer who waits until the last week to spend, will find the selection limited -- the top one or two items may not be there at all, and will certainly not be there at half price."

Despite this warning, Brewer is not overly optimistic about this holiday season.

"Consumers have been very very careful with their spending. We've seen relatively soft figures for the last five months," when increases above last year's level hovered around 5 percent.

While expecting to see a similar increase during the Christmas season, Brewer noted that the boost would be far below last year's sales gain of 17 percent.

Brewer is not alone in his caution.

"The consumer doesn't seem to be spending quite as much as last year," noted Lawrence A. Wilson, assistant treasurer for Circuit City Stores.

"We're looking for a good Christmas, but not the type of increases we saw last year which was phenomenal" when, spurred by the demand for consumer electronics, sales increased by 33 percent, he said.

"This year, sales will be modestly above last year," he added.

"This is really a tough season to read," added Frederic J. Bell, senior vice president of W. Bell & Co.

"Overall, things are sluggish and the season has gotten off to slow start," he said.

"Built in against us this season is the six fewer days of the season. Although there will still be the same number of people on a person's Christmas list, the more time people have to think about it, the more time they have to get marginal gifts, and the more likely sales would be stronger," Bell added.

Despite sluggish sales, retailers should not suffer economically, noted Ruchlamer of Shearson Lehman Bros. Having cut their inventories sharply, retailers are in better shape financially this year. "The bottom line will be up across the board," she predicted.

Despite modest sales increases, "10 to 20 percent increases in profits -- after losses last year -- would not be unusual," she said.

To economists, the amount that consumers spend this Christmas will be a critical barometer of the nation's economic strength.

"Consumer spending has clearly led the economy this year," said Sandra Shaber, director of consumer market forecasts at the economic forecasting firm Chase Econometrics. "It was the major factor in keeping the economy going all year long, and in the fourth quarter, with every other sector of the economy fairly weak, if you don't look to the consumer [for strength] I don't know where else you'd look."

Overall, most economists and financial analysts expect to see about a 5 percent sales gain this Christmas season over last year's level. That would be the smallest increase since the recession year of 1981.

The reason for this relatively pessimistic forecast lies in a host of economic statistics. For one thing, consumer credit reached an all-time high in September, when 19.2 percent of consumers' disposable income was used to pay installment loans and credit cards. Although the percentage ratio dropped slightly to 18.9 percent in October, it still remains very high, economists note.

At the same time, personal savings, in relation to income, reached a record low in September -- 1.9 percent of disposable income -- thanks in large part to the huge incentives offered by automobile dealers during that month. Although the ratio climbed back to 2.9 percent in October, it is still substantially below the 6.5 percent ratio recorded a year ago. "That's the sharpest erosion on record," said Stephen Roach, senior economist for Morgan Stanley & Co. Inc.

Roach also noted that 2.5 percent of all installment loans are now delinquent. While that may not seem like a high number, Roach said it was signficantly above the 2 percent rate posted at the beginning of 1984. What's more he said, 7 percent of all mortgage loans are also late.

"The cumulative effect of these numbers shows that the the consumer is strapped," said Walter F. Loeb, a retailing expert with Morgan Stanley. "As a result, he will inevitably have to cut back.