Sleep Changes that Come with Age

Over a typical lifespan, the amount of time we spend each day sleeping declines. Newborns spend from 16 to 20 hours asleep each day. Between the ages of one and four, total daily sleep time decreases to about 11 or 12 hours. This gradual decline continues through childhood, such that an adolescent will need—though not necessarily get—about nine hours of sleep to function at his or her best. Adults through middle age need at least eight hours, and although the elderly may still require up to eight hours, they may struggle to obtain those hours in one block.

Age-Related Sleep Problems

Given what we know, late childhood may well be the "golden age" of sleep during a lifetime. Beyond the age of 11 or 12, sleep disturbances begin to creep in. In fact, nearly 7 out of every 10 adults experience problems that affect sleep quality.

A number of sleep problems are particular to adult women. Half of them report sleep disturbances during their menstrual periods; three-quarters of expectant mothers report that sleep is more disturbed during pregnancy; and many experience disrupted sleep during menopause, in part due to nighttime "hot flashes."

Insomnia and disrupted sleep in elderly people are a common side effect caused by many chronic medical conditions such as arthritis, congestive heart failure, depression, and gastroesophogeal reflux disorder. Respiratory disorders, such as sleep apnea, which cause multiple arousals during the night, also become more common as people age. Other problems, such as restless legs syndrome, which results in an uncontrollable need to move one's legs while drifting off to sleep, or periodic limb movements, which cause jerking of the feet or legs during the night, can make it difficult to fall asleep or lead to highly fragmented sleep. Unfortunately, sleep problems in older adults often go undiagnosed and untreated simply because many people believe sleep problems are a normal part of aging or that nothing can be done to help them sleep better. Thankfully, treating any underlying medical disorders can dramatically improve sleep.

Because most older adults are less able than younger adults to maintain sleep, the elderly suffer disproportionately from chronic sleep deprivation. Sleep deprivation may cause individuals to unintentionally nod off during daytime activities. Late afternoon naps can also reduce a person’s ability to sleep through the night, thus potentially worsening insomnia. Learning how the internal clock and sleep drive interact, and how they limit when good sleep can occur, can help people devise strategies that will help them maintain quality sleep as they age.

- Excerpt from A Life of Change
- Harvard Medical School, Division of sleep medicine