Some days I feel incredibly ancient. Not in age or my knowledge of modern music (although my millennial daughter may disagree), but in how my body feels. There are mornings when everything is rusty and creaky.

You know what I mean: the stiffness and dull aches (and accompanying grunts and groans) that occur after you wake up. These feelings often go away in about five or 10 minutes. Some mornings are worse than others, and sometimes I awaken stiffness-free.

Why does morning stiffness happen?

“It’s not known why morning stiffness occurs, especially as people age, but the only common thread is that it occurs after long bouts of inactivity,” says Dr. William Docken, a rheumatologist with Harvard-affiliated Brigham and Women’s Hospital. “That is why you often feel so stiff when you wake up, since sleeping is when you are inactive for the longest continuous time.”

However, any prolonged period of sitting also can cause stiffness, like watching TV, working at the computer, or riding in the car.

A simple remedy for stiffness

To break up long stretches of sitting, set a timer on your phone or computer to remind you to move around every 20 to 30 minutes. Walk around your home or neighborhood, do some household chores, or even a quick set of lunges or marching in place for a minute.

Another option is the following A-B-C routine. The three moves focus on the main stiff areas: shoulders, back, and legs. Do this in the morning to get loose, during your breaks from sitting, or whenever you feel a little “ancient.”

A: Arm sweeps

Stand up straight with your feet together. As you inhale, sweep your arms out to the sides and up toward the ceiling. As you exhale, sweep your arms back down to your sides. Repeat five to 10 times.

B: Back bend

Stand up straight with your feet slightly apart. Place your hands on your lower back with your fingertips pointing down. As you inhale, roll your shoulders back and gently lift your chest toward the ceiling, arching your back to the point of comfort. You should be gazing up at the ceiling in front of you. (Be careful not to overextend your neck.) Hold for three to five breaths. Release on an exhalation. Do three to five reps.

C: Chair pose

Stand with your feet about shoulder-width apart and arms down at your sides. Raise your arms overhead. As you exhale, bend your hips and knees and lower yourself into a squat position (as low as comfortable), keeping your back straight. Hold for a few seconds, and stand as you lower your arms to complete one rep. Repeat the movement until you do five to 10 reps. You can also raise your arms to chest height only, or keep your hands on your thighs, so you focus only on your lower body.