Not so fast on that makeover

Welcome, folks, to 2006, where the resolutions are stacking up like, well, like discarded resolutions from last year. While we are overjoyed that fitness is near the top of your do-better list, we begin this annum with a word of caution: Don't push it.

That's right. Whether you've taken off the last 30 years from your regular workout regime, or if you were in decent shape in early November but simply IGNORED OUR ADVICE TO AT LEAST WALK BRISKLY EVERY DAY DURING THE HOLIDAY SEASON TO RETAIN SOME LEVEL OF FITNESS (sorry for raising our voice so early in the year), we want you to get back to regular activity slowly. You cannot nullify several weeks or decades of sloth with one or two Category 5 workouts.

When starting back after a layoff, remember a simple formula: 1:1, says Steven M. Horwitz, Maryland director of the National Strength and Conditioning Association. "If you've been out three weeks, it will take three weeks to get back to where you were. If you were out six weeks, it will take six weeks to get back."

Horwitz, a chiropractor and certified trainer, suggests starting back with "the 50-50 rule - 50 percent of your standard exercise intensity before you slacked off and 50 percent of the time." So if you used to cycle for 45 minutes at an intensity of six (on a 1-10 scale), start with 23 minutes and an intensity of three.

If you've been off duty for several months or years, start wherever you're comfortable, aiming toward a brisk 20-minute walk four times per week. As you step up, abide by the usual advice: Increase no more than 10 percent at once, in weight, time or intensity.

Horwitz says the injuries he sees most often in people pushing too hard to regain fitness are back injuries, muscle strains and more-serious joint injuries (like damaged cartilage). The vast majority result from tissue overload - excess pressure on unprepared body parts.

"You're not flexible enough" after a layoff, Horwitz says. "You've been detrained: You're weaker and tighter and - boom! - you get hurt."

Besides, says Jeff Horowitz (no relation), an assistant professor in the division of kinesiology at the University of Michigan, "it is very difficult in a quantifiable way to expend a huge amount of calories in an exercise session."

Meaning that you won't be able to burn off all your holiday gluttony by locking yourself in the gym. Most exercise sessions burn 200 to 400 calories, the equivalent, Horowitz says, of "a few appetizers at a holiday party."

He adds that a single aerobic exercise session carries benefits beyond fitness, and that the more regular the workouts, the better. "One session of exercise can markedly improve insulin sensitivity," a concern for people with type 2 diabetes, Horowitz says. The effect lasts up to two days. One exercise bout also improves blood pressure and heart disease risk.

So as you slip on your workout clothes brimming with resolve, keep in mind that your real goal isn't to lose the gut by Feb. 1 or punish yourself for accumulated sins. It's to make sure you're still working out, uninjured and hale, in two weeks - and two years.