I'm not a kid anymore -- I faithfully warm-up a few minutes before any cardiovascular endeavor, unless it's an all-out sprint chasing down a cab. But I never thought about warming up before getting out of bed.

One expert over at "purehealthMD" says that's exactly what you should do. Overnight muscles can stiffen up, lubricating joint fluid can actually thicken and ligaments are less stretchy. I know my reconstructed achilles tendon says a stiff 'hello' to me each morning.

So before you swing your legs over the side of bed, try these five stretches first:

• Trunk rotation -- Lie on back with knees bent, feet on bed. Roll knees side to side with knees together. Ten reps, each side.
• Ankle pumps -- Lie on back with legs straight. Pump feet down, then up as far as possible, hold each position about 10 seconds. Ten reps. Back off a bit when pointing down if your calves cramp.
• Single knee to chest -- Pull one knee toward chest and hold for 20 seconds. Repeat on opposite side. Three times per side. This move is safer for your back than the double leg version.
• Arm slides -- Lie on back with knees bent/feet on bed. Slide back of arms up over your head slowly -- like an arm-only snow angel. Ten reps.
• Foot slides -- On back with legs out straight, slowly slide one heel toward your rear, then straighten. Repeat on other side. Ten reps per leg.

Now slip into your favorite fitness outfit and take your limber self to the gym.