The bad news is right

there in the mirror.

You've been dodging

it for weeks like

Count Dracula, but one day, just out of the shower, you accidentally turn and . . . there staring back at you is what seems to be a giant egg custard with terry- cloth trim. You know you've got it: the dreaded Desk-Bound Bloat, aka Federal Physique or Orson Welles Syndrome. And you've got it bad: When somebody jostles you on the subway, you keep jiggling for two stops; reloading the stapler makes you short of breath; and when you sit down, your rump oozes over the seat like a flat tire on the highway to health.

And why not? Like most of Washington's office-locked legions, your big exertion of the day is dialing a 10-digit number. Worse yet, you spend eight to 12 hours hunched in a spine-warping chair designed by some art-school fruitcake with a criminal disdain for human anatomy. And you squander your break time chomping the Cheetos till your arteries clog with lard. No wonder you have all the muscle tone of day-old clam dip and look like something that ought to be in a jar at the Smithsonian.

Well, no more excuses, Flabbo. It's either shape up or you'll be shipping out well ahead of your slot on the actuarial tables.

And the good news is right there in the office: Just five minutes of the following sweatless exercises, repeated two or three times a day, will start rebuilding your body-- all without leaving your beloved desk! You won't lose weight (although taking a stroll instead of a strudel and avoiding the elevator will help), but you'll look better, feel better and improve your job performance. THAT GUT FEELING

With your hands on the seat of your chair, put your knees together and slowly lift both feet off the floor. Congratulations: You have discovered your abdominal muscles. As with most deskercises, try for a dozen repetitions and then quit for a while. But keep at it--these are important. After general tension, office workers' most common complaint is back pain. And "it all stems from weak abdominal muscles," says Shelley Liebman, author of Do It At Your Desk (Tilden Press) and owner of The Home Stretch, a local fitness outfit whose clients include the fat-phobic OMB and the Wilmer, Cutler & Pickering writ works. For solid-waist treatment, she also recommends these: While seated, drop sideways and touch the floor about a foot from your chair; or lean forward and touch your toes.

Florida scientist Dr. Keith Andrews and co-author Bruce Andrews add these sedentary gut-busters in their bookCommuter Calisthenics (Fitness Alternatives Press): Place both hands on your knee and push down while simultaneously trying to raise your leg. Or put your hands on the seat on either side of your hips, lean forward and hoist yourself off the chair. Move your hips from side to side, then back and forth. Or try this one from the Maryland Commission on Physical Fitness: Lift your left leg and touch it with your right elbow, then vice versa. You'll look like you're auditioning for Soul Train--but that's better than understudy for The Blob. (For the MCPF's free poster showing an office exercise program, write them at 201 W. Preston St., Baltimore 21201.) REARMAMENT

Build up your arms by locking your hands together chest high and pulling outward; your biceps by placing both palms on the underside of the desk and pushing up; your shoulders by holding a fist up at shoulder height and pushing it toward the ceiling while holding it down with the other hand--tones up "the back of the upper arm," say the Andrews, "where the flab first shows." Liebman also suggests push-ups: While waiting for the copier, stand 3 or 4 feet from the machine, lean over and put both hands on the top; or in your chair, stick your legs out straight, hands on the armrests, and raise yourself out of your seat. Tied up on the phone? Lift a light weight with your free arm (make your own, Liebman says, out of a plastic jar filled with beans or pennies). For the forearms, she suggests squeezing a rubber ball; afterward, plop it down on the floor, kick off your Hush Puppies and you've got a private foot massage. PRIME PARTS

For a firmer chest, place both palms together at breast height and push. Been eyeing some costly patent gizmo to pump those pectorals? Forget it, says Liebman --use surgical tubing. Wrap it around each hand and pull sideways from chest height. Need more tension? Double the tubing. For the biceps, start at the breast and stretch your arms all the way around to the sides; for the triceps, do it diagonally behind your back, like drying off with a towel. Will it look ridiculous? Not when it's sleeveless-dress season.

Weak back? From sitting position, lean down, put your forearms under your thighs, lock your hands and try to sit up. You say you can't SEE your knees? Then at least start toning your thighs: Push your knees together hard, let them move slowly apart and repeat. And make a habit of contracting your buttocks at every discreet opportunity; each month you'll look more like Nureyev and less like the Michelin tire boy.

Finally, even the most indolent memo-jockey should follow this general precept: Get up as often as possible and move around. Just boosting your bulk out of the chair is good exercise, stimulates circulation and burns hundreds of calories a week. And while you're up, ask the boss to sponsor an office fitness program--one of the cheapest ways known to reduce absenteeism, increase productivity, boost morale and promote survival of the fattest.