Getting less than five hours sleep a night raises older people's risk of premature death by a quarter, according to new research.
They are 40 percent more likely to develop at least two life-threatening illnesses such as heart disease, cancer and diabetes.
Lead author Dr Severine Sabia, of University College London, said: "Multimorbidity is on the rise in high income countries and more than half of older adults now have at least two chronic diseases.
"This is proving to be a major challenge for public health, as multimorbidity is associated with high healthcare service use, hospitalisations and disability.
"As people get older, their sleep habits and sleep structure change. However, it is recommended to sleep for seven to eight hours a night - as sleep durations above or below this have previously been associated with individual chronic diseases.
"Our findings show that short sleep duration is also associated with multimorbidity."
They are based on 7,864 over 50s in the UK. The men and women, members of the Whitehall II study, were tracked for 25 years.
Dr Sabia said: "To ensure a better night's sleep, it is important to promote good sleep hygiene, such as making sure the bedroom is quiet, dark and a comfortable temperature before sleeping.
"It's also advised to remove electronic devices and avoid large meals before bedtime. Physical activity and exposure to light during the day might also promote good sleep."
Blue light from smartphones and tablets fools the brain into thinking it's daytime - blocking a sleep hormone called melatonin that is a potent antioxidant.
Late night snacking can lead to obesity by reducing metabolism and increasing fat storage.
Dr Sabia and colleagues compared the impact of self-reported sleep duration on each participant.
They examined the relationship with mortality and whether they had been diagnosed with two or more chronic diseases.
At 60, those who slept five hours or less a night were a third (32%) more likely to have multimorbidity than peers who managed seven - rising to 40 percent at 70.
Shorter slumber also increased the risk of one serious condition by 20 percent. It was linked to a 25 percent higher risk of death during the study period.
There was no clear association between sleeping more than nine hours a night and multimorbidity in healthy individuals.
However, there was a 35 percent higher risk of developing another illness among those who had already been diagnosed with a chronic condition.
This may be due to underlying health problems affecting sleep. Living with multiple chronic conditions is common with increases in life expectancy.
The study in PLoS Medicine supports the promotion of good sleep hygiene in middle and old age.
It is one of the first to connect poor sleep with multimorbidity - the co-occurrence of two or more chronic conditions.
Jo Whitmore, senior cardiac nurse at the British Heart Foundation, said: "Getting enough sleep allows your body to rest.
"There are a host of other ways that poor sleep could increase the risk of heart disease or stroke, including by increasing inflammation and increasing blood pressure.
"This research adds to a growing body of research that highlights the importance of getting a good night's sleep."
Margaret Thatcher famously slept only four hours a night. The former Prime Minister died with dementia in 2013 at the age of 87.
The body heals and repairs damages tissues during sleep - including the heart and blood vessels.
Not getting enough has been linked to every life threatening illness - including Alzheimer's.
The Whitehall II study was established in 1985 to investigate the causes of social inequalities in health.
Dr Sabia added: "Our study based on data on more than 7,000 men and women followed up for 25 years reports short sleep duration from mid to late life to be associated with risk of chronic disease and subsequent multimorbidity."
Don't miss the latest news from around Scotland and beyond - sign up to our daily newsletter here .
