BOSTON — As we age, we experience decreases in everything from hair and hearing to memory and muscle. Height is also on the list. Starting at about age 40, people typically lose about half an inch each decade. Why do we shrink, what are the consequences, and what can we do? The December issue of Harvard Health Letter answers these questions.

What causes height loss?

Fractures of the bones of the spine can contribute, as can slouching.

What are the consequences?

For many people, losing a little bit of height doesn’t cause any health problems. But severe kyphosis (the medical term for being hunched over) sometimes affects breathing and causes neck and back pain.

What can I do to slow down shrinkage?

Improve your posture. Focus on exercises that will strengthen back muscles. One involves lying on your stomach and then lifting your head and shoulders. Yoga or tai chi are other options. Strengthen your bones. The other way to limit height loss is to keep bones strong to prevent fractures. The single best way to do that is to stay active. Getting enough calcium and vitamin D is also important.

Also in this issue:

A gap in Medicare prescription drug coverage Importance of carbon monoxide alarms The politics of diagnostic codes and smoking News on vitamin B and the brain Side effects of over-the-counter pain relievers A doctor answers: If I have chest pain, when should I call 911?