If you've noticed that you seem a little shorter than you used to be, you're probably not imagining it. Research confirms that most people lose measurable height as they age, and the process begins earlier than most of us expect.

The primary culprit is the spine. Between each vertebra sit intervertebral discs — cushions of cartilage that absorb shock and give the spine its flexibility. Over time, these discs gradually lose water content and compress. Add up the tiny reductions across all 23 discs in the spine, and the cumulative effect can be significant.

Posture also plays a role. The muscles and ligaments that hold the spine upright weaken with age, leading to increased curvature — the stooped posture sometimes associated with older adults. Osteoporosis, which causes bones to become more porous and fragile, can lead to vertebral compression fractures that dramatically reduce height.

The numbers are sobering. Men typically lose about an inch of height between their 30s and 70s. Women lose slightly more — roughly one and a half to two inches over the same period, with the rate accelerating after menopause due to hormonal changes that affect bone density.

The good news is that much of this is preventable or at least delayable. Weight-bearing exercise helps maintain bone density. Adequate calcium and vitamin D intake are essential. Core strengthening and postural work can help counteract the muscular weakness that contributes to spinal compression.

So yes, you are getting shorter. But the rate at which you shrink is, to a meaningful degree, within your control. Stand tall while you still can — and do the work to keep it that way.