We know that the prevalence of insomnia increases as we age, and there are a number of reasons for that, reports MD Magazine.
One of the major and most important reasons is that sleep seems to naturally fragment as we age. As we age, we wake up more. We sleep less during the course of the night. And the older individuals become sleepier during the course of the day and nap more. In addition, they seem to have a shortened amount of slow-wave sleep or some of the deeper stages of sleep, and an increased amount of shallow sleep or stage I sleep. There seems to be a natural deterioration in the sleep-wake cycle as we age.
The question has always been, are these changes a result of the natural process of aging? Or are these caused by medical and psychiatric and other conditions, which also increase in prevalence as we age? And the data seem to suggest that not all these changes are due to comorbid conditions. That there seems to be a natural degradation in sleep as we age. We simply cannot sleep as much as we age.