Did you know that you will lose height as you get older? You’ll get shorter. That may be something you knew, but ignored — until it began happening. Those precious few inches which made you 6-feet tall or 5-foot-2 may in time devolve to 5-foot-8 for a previously tallish guy or 4-foot-9 for a now-short woman. Two, three or even more inches; gone.

Much of the shrinkage happens in the spine. The bulbous discs between the vertebrae get thinner with time. In addition, the connective tissues contract, slightly shrinking the joints, which adds to height loss.

You don’t need to be middle-aged for this to begin happening. The shrinkage process begins in the late 30s.

But you can slow it down considerably, or even help prevent it, with the right kind of conditioning. Training should start by the age of 40. But even if you’re older than 60 and have already lost height, you can still get some of it back.

The main type of conditioning you’ll need are stretching exercises. Next in importance are aerobics or power moves that flex all the body’s joints at different angles. It’s best to do the stretch work just before bedtime, because during the day, the spine and other joints get compressed by the combination of your body weight and gravity.

However, while you’re lying down to sleep, there’s no weight on the joints, so they decompress. That’s why you’re tallest when you first get out of bed. Check this for yourself by measuring your height first thing in the morning, then again just before you turn in.

Stretch a little

If stretched at the end of the day, when the body is already somewhat warmed up by the day’s activity, connective tissues like ligaments and tendons will become more pliable. Because the joints aren’t being weighed down, the tissues are able to hold this extra flexibility for the hours while you sleep.

Do classic moves, such as the sitting or standing hamstring stretch, the groin stretch, the core twist that stretches the long lat muscle in the back. The most important stretches are those for the spine. Here are two:

1. The isometric stretch: Lie on the floor with legs straight and arms spread out. Start by pulling your head up along the floor, thus stretching your neck. Then stretch your neck. While pulling it into a stretch, turn your head slowly from side to side so you stretch each one of the 20 pairs of muscles in the neck. Continue the stretch downward, paying special attention to the spine and pelvis.

2. The spine stretch: Lie on a couch with the couch arm under your hips (a large exercise ball also can be used). Let your upper body hang down, hands on the floor with no pressure. As the body hangs, the weight of the head (about 12 pounds) will stretch out the spine.

Just stretching the tissues is not enough, however. Unless the joints are used, flexed over and over again, connective tissue will contract and get stiff. As a result, you’ll shrink. One of the best exercises for flexing and warming all the joints is jumping rope, if your knees are in shape to do it. Most kinds of full-body aerobics classes will work the joints.

Just remember these two basic facts: Stretching your spine and joints should be done at least four times a week, or even better, daily. Each session should last 10 minutes or more. Meanwhile, the rules are different if you want to start regaining your height but have been sedentary.

If you’ve been spending most of your day sitting around, you may have to train just to have the balance and coordination to do a hamstring stretch or to get down on the floor for the isometric exercise.

But that’s another column.