People with diabetes were more likely to die over a multiyear period if they reported getting four hours or sleep or less each night, or getting nine or more hours of sleep, according to a new study published in the journal Cardiovascular Diabetology.
It’s well known that people who don’t get enough sleep are at higher risk for certain diseases and death than people who typically sleep more each night — but sleeping too much may also be a sign of certain diseases and it also linked to worse health outcomes. When it comes to your mental and cognitive health, research shows that seven hours of sleep each night may be the sweet spot — and getting the right amount of sleep may limit cognitive decline in the early stages of Alzheimer’s disease. Sleeping well may also reduce your risk of developing diabetes, and if you already have diabetes, quality sleep is linked to lower blood glucose after eating breakfast. Sleep disturbances are linked to a higher death risk in people with diabetes, while treating sleep disorders has been shown to help improve diabetes-related outcomes. Sleeping enough has also been linked to lower calorie consumption, while getting less sleep is linked to higher body fat levels. If you’re looking to get better sleep, research also points to some strategies that might help, such as getting more daytime outdoor light exposure and getting enough exercise.
For the latest study, researchers looked at the risk of dying in 12,526 people with type 2 diabetes ages 30 and older over a median follow-up period of 10.82 years, with each participant followed for a minimum of three years. A total of 2,918 study participants died during the follow-up period, and those who reported sleeping between five and seven hours per night had the lowest overall death risk. But the risk of dying varied based on several factors, the researchers found.
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Not surprisingly, when it came to sleep duration, most participants reported what is widely considered to be a moderate amount of sleep. Only 1.64% of participants got less than four hours of sleep, and 16.04% got five to six hours of sleep each night. Another 26.15% reported getting seven hours of sleep, 29.32% got eight hours of sleep, and 23.23% got nine to 10 hours of sleep, while 3.62% got more than 10 hours of sleep.
Shorter-, longer-than-moderate sleep durations linked to increased death risk
Compared with participants who got seven hours of sleep, those who got four hours of sleep or less, or nine or more hours of sleep, were more likely to die. Those who slept four hours or less were 41% more likely to die, while those who slept nine to 10 hours were 37% more likely to die and those who slept more than 10 hours were 82% more likely to die. For death from cardiovascular disease in particular, the risk was 54% higher for those who slept four hours or less, 34% higher for those who slept nine to 10 hours, and 88% higher for those who sleep more than 10 hours.
The researchers found that the death risk linked to getting more than, or less than, seven hours of sleep was greater among participants ages 65 and older — these people were four times as likely to die if they didn’t report getting seven hours of sleep. A sleep duration of less than or more than seven hours was also linked to a 60% higher death risk for people with a diabetes duration of at least five years, a 69% higher death risk for people diagnosed with diabetes at or before age 45, a 76% higher death risk for people who used insulin, and a 31% higher death risk for people with an A1c level (a measure of long-term blood glucose control) of 7% or higher.
“A J-shaped association was observed between sleep duration and all-cause and [cardiovascular] mortality,” with a sleep duration of five to seven hours linked to the lowest death risk, the researchers concluded. But it’s important to note that these results are purely observational — they don’t mean that your risk of dying will be lower if you intentionally limit the amount you sleep, or if you try to sleep longer if you can’t sleep as long as is recommended.
Want to learn more about sleeping well with diabetes? Read “Getting the Sleep You Need,” “Eating for Better Sleep” and “Feeling Fatigued: Here’s How to Fight It.”