Sleep is the best medicine. Although older adults need as many hours of sleep as younger adults – between seven to nine hours each night – we often hear the commonly held but mistaken belief that you need less sleep as you age.

Disruption of sleep can cause memory problems, depression, a higher susceptibility to falls and also an early death.

In the US, insomnia is the third most common reason for a medical visit, behind only headaches and the common cold. As sleeping patterns change for older adults – going to sleep earlier, getting up earlier and napping during the day – it becomes more difficult to fall asleep at night.

Once asleep, older adults spend less time in deep sleep – rapid eye movement (REM) sleep – and as a result they are often light sleepers. By themselves, even these normal changes can disrupt sleeping patterns. More than half of older adults have a sleep disorder. The rate is higher among long-term care facility residents. Although researchers have described more than 70 sleep disorders, four hold top billing, including insomnia, sleep apnoea, restless legs syndrome and narcolepsy.

Among older people, women experience insomnia more than men. Insomnia, which is the most common sleep problem in adults aged 60 and older, results in trouble falling and staying asleep. About 60 million Americans a year have insomnia, which tends to increase with age. It affects about 40 per cent of women and 30 per cent of men.

Individuals who are awake for a fifth of the time they were in bed were more than twice at risk of an early death

Sleep apnoea is a disorder of interrupted breathing during sleep. It is usually related to fat build-up or loss of muscle tone and when muscles relax during sleep the windpipe collapses during breathing. Sometimes this is accompanied by loud snoring (though not everyone who snores has this disorder). An estimated 18 million Americans have sleep apnoea.

Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) – an unpleasant crawling, prickling or tingling sensations in the legs and an urge to move them for relief – affects as many as 12 million Americans. In one study, RLS and PLMD accounted for a third of the insomnia seen in patients older than 60.

Older adults with narcolepsy have frequent ‘sleep attacks’ at various times of the day, even if they have had normal amounts of night-time sleep. Narcolepsy affects an estimated 250,000 Americans who have attacks lasting from several seconds to more than 30 minutes. The disorder is usually hereditary, but is occasionally linked to brain damage from a head injury or neurological disease.

As disruption of sleep becomes more common as we get older, the consequences are also becoming more apparent. In 2003 Amanda Dew and her colleagues at the University of Pittsburgh, the US looked at one such consequence of disturbed sleep and how it influences an early death. After controlling for things that can also influence death, such as age, gender and how healthy they were, they then could predict death based on their sleep patterns.

Individuals who take longer than 30 minutes to sleep or are awake for a fifth of the time they were in bed were more than twice at risk of an early death. Even those who either dreamt too much or too little (Rapid Eye Movement sleep) were nearly twice as likely to die earlier. Sleeping just the right amount promotes longevity. Some clinical research now focuses on the role of melatonin in sleep management. Some serious conditions need consultation, while others just require a more disciplined approach to going to sleep.

Follow a regular sleep schedule. Go to sleep when tired but get up at the same time each day, even on weekends. Try to avoid napping during the day and make an effort to get outside in the sunlight every day. Stay away from tea or coffee late in the day. Although alcohol might make you sleepy, it might also wake you up in the middle of your sleep.

Exercise and light meals also contribute to better sleep. It also seems to help to have a cooler room at night. Training yourself to sleep better might be the best investment in your day-to-day schedule. You can sleep yourself to a longer healthier life.

Mario Garrett was born in Malta and is currently a professor of gerontology at San Diego State University in California, US.