This Is How Much Sleep You Need to Lower Your Type 2 Diabetes Risk

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Female lying in bed on her back with her hand covering her face — A recent study shows that getting between 7 to 7.5 hours of sleep may help lower your risk of diabetes. Image Credit: Artem Zhushman/Stocksy

A recent study suggested that 7 hours and 18 minutes of sleep may be the optimal amount to reduce the risk of insulin resistance, a precursor to type 2 diabetes.
The study noted that catching up on sleep on the weekend may actually increase the risk of impaired glucose metabolism.
Sleep, along with other lifestyle changes, can greatly reduce your risk of insulin resistance and type 2 diabetes.

There is a long-standing relationship between type 2 diabetes and sleep. Type 2 diabetes can disrupt your sleep, while certain sleep disorders can increase your risk of developing it.

“There are many benefits to getting adequate sleep. These include better cognitive function, emotional well-being, immune function, weight management, athletic performance, and even longevity,” Dav id Cutler, MD, board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, told Healthline.

“Improved metabolic function and a lower risk of diabetes is also dependent on getting the right amount of sleep.”

A recent study published in the open-access journal BMJ Open Diabetes Research & Care suggests that 7 hours and 18 minutes may be the “sweet spot” for reducing your risk of insulin resistance.

Insulin resistance is when cells in your muscles, fat, and liver don’t respond properly to insulin, leading to a buildup of glucose in your blood. This is a precursor to type 2 diabetes.

“Importantly, there appears to be a bidirectional relationship between sleep and metabolism. For instance, poor glycemic status itself has been linked to a higher likelihood of both short and extended sleep durations, as well as sleep disorders,” the researchers of the recent study said.

“This creates a potential vicious cycle wherein metabolic dysregulation disrupts normal sleep patterns, and the resultant abnormal sleep (including extended duration) further aggravates metabolic health.”

About 7.5 hours of sleep may prevent insulin resistance

The study included 23,475 participants, ages 20 to 80, from serial waves of the National Health and Nutrition Examination Survey (NHANES) between 2009 and 2023. Of these, 10,817 had data available on weekend sleep duration.

The researchers explain that the estimated glucose disposal rate (eGDR) is considered a reliable substitute for insulin resistance.

eGDR is a measure of insulin sensitivity. The higher the eGDR, the lower the risk.

The study’s researchers set out to investigate the association between weekday sleep duration and eGDR, as well as the moderating effects of weekend catch-up sleep.

The researchers categorized weekend sleep as:

none
up to 1 hour
1 to 2 hours
more than 2 hours

They calculated the eGDR using a formula that involved:

waist circumference
glycated hemoglobin (HbA1c)
hypertension status

The average eGDR was 8.23. Individuals slept for an average of 7 hours and 30 minutes on weekdays. A little over 48% of participants reported catching up on sleep on the weekend. They slept for an average of 8 hours during this time.

Analysis of the data showed an inverted U-shaped relationship between sleep duration and eGDR. The “sweet spot” appeared to be at 7 hours 18 minutes.

Below this threshold, greater nightly sleep was associated with higher eGDR. Above the threshold, more nightly sleep was associated with a lower eGDR. This was particularly true among females and those between the ages of 40 to 59.

Further analysis showed that for those sleeping less than the optimal threshold during the week, 1 to 2 hours of catch-up sleep at the weekend was associated with a higher eGDR compared with no catch-up sleep.

For those who slept more than the optimal threshold during the week, 2 hours of catch-up sleep at the weekend was associated with a lower eGDR after accounting for potentially influential factors, such as:

lifestyle
ethnicity
marital status
educational attainment

“What a great study, and so good to see further evidence that the myth of 8 hours of sleep is too much. This supports a prior study between the U.K. and China, which also showed 7 hours to be optimal for mental health and cognitive performance,” said Alex Dimitriu, MD, double board certified in Psychiatry and Sleep Medicine and founder of Menlo Park Psychiatry & Sleep Medicine, who was not involved in the study.

“In the end, our lives exist on a spectrum between sleep and wake — too much sleep is often linked to illness and depression, while too little sleep is linked to anxiety and insomnia. Our autonomic nervous system sets this balance, and here we see additional support for an optimal balance — around 7 hours of sleep.”

This was an observational study, which means that no firm conclusions about cause and effect can be drawn. The researchers acknowledged that the study relied on self-reported data. They also noted that they couldn’t rule out reverse causation, meaning that disrupted glucose metabolism may interfere with sleep rather than the other way around.

“These correlational findings suggest that sleep patterns, particularly weekend recovery sleep, may be relevant for metabolic regulation in diabetes and could inform considerations for healthcare professionals in managing patient care,” said the research team.

“Sleep loves regularity and rhythmicity — and is one of the biggest metabolic levers we have. This study adds further support for the importance of sleeping about 7 to 7.5 hours per night. No need to stress that you didn’t sleep 8 hours. But also, don’t let this be a slippery slope to start getting 6,” said Dimitriu.

How is sleep related to diabetes risk?

Previous research has shown a direct link between sleep habits and type 2 diabetes.

Individuals with type 2 diabetes often experience issues with sleep. This can negatively affect their mood, health, and quality of life.

“Sleeping less than 7 hours may be associated with an elevated state of alertness, which also comes with elevated adrenaline and cortisol levels, all of which can raise blood glucose. Conversely, sleeping too much may be associated with other illnesses and lack of mobility — both of which can also have negative metabolic impacts,” said Dimtriu.

The reverse is also true, however. Sleep disorders, like obstructive sleep apnea, can increase the risk of metabolic diseases, such as type 2 diabetes.

“Diet and exercise are also major determinants in controlling the development of diabetes. But since poor sleep will often trigger a worse diet and a diminished capacity for exercise, focusing on sleep can target many birds with one stone,” said Cutler.