Regularly getting just over seven hours of sleep — or, if you’re the meticulous type, seven hours and 18 minutes — per night could be one of the keys to preventing type 2 diabetes.
People who got less than 7.3 hours per night, on average, had a higher risk of insulin resistance. So did people who got more than 7.3 hours.
A few extra weekend hours helped mitigate the risk of insufficient weekday sleep, but for people who already got the right amount of sleep during the week, extra weekend sleep slightly raised insulin resistance risk.
“The take home message is not that you need exactly seven hours and 18 minutes of sleep, but that roughly seven to eight hours of good quality sleep most nights is recommended for metabolic health,” says Scott Isaacs, MD, an endocrinologist and adjunct professor at the Emory University School of Medicine in Atlanta.
“If you are consistently sleeping less than this, weekend catch up of an extra hour or two may help, but it will not fully undo the impact of chronic weekday sleep deprivation.”
The Sweet Sleep Spot for Preventing Insulin Resistance
Researchers analyzed data from nearly 25,000 people aged 20 to 80 between 2009 and 2023, using a formula including waist circumference, fasting blood sugar levels, and blood pressure to calculate a measurement called estimated glucose disposal rate (eGDR). Lower eGDR rates have been tied to greater risk of insulin resistance.
These figures were combined with self-reported weekday sleep times. A subset of about 11,000 participants also provided self-reported weekend sleep hours.
Here’s what the research team found:
- On average, 7.3 hours of sleep was the sweet spot for reducing the risk of insulin resistance. Insulin sensitivity improved as people approached the 7.3 hour mark, then worsened when they slept beyond that.
- Women and adults ages 40 to 59 were especially prone to insulin resistance if they slept more than 7.3 hours on weekdays.
- Getting an extra one to two hours of sleep on the weekends was tied to lower insulin resistance risk for people who were not getting 7.3 hours of sleep on weeknights.
- Getting more than two hours of weekend catch-up sleep was linked to higher insulin resistance risk for people who were already getting 7.3 hours of sleep during the week.
“This study reinforces that both too little and too much sleep are linked to insulin resistance,” says Dr. Isaacs. “The results suggest that modest catch-up may benefit people who are chronically sleep deprived, but oversleeping on weekends is less helpful for those already above the optimal range.”
Lead study author Zhanhong Fan, a researcher at Nantong University in China, says the findings highlight how common catch-up sleep is utilized as a coping method.
“This is likely due to ‘social jetlag,’ where shifting your sleep schedule significantly disrupts your body’s internal clock, leading to metabolic disturbances and poorer blood sugar control,” Fan says.
“But there is no weekend compensation for sleep. The healthiest approach for your metabolism is to prioritize consistent, moderate sleep over drastically varying your sleep schedule between weekdays and weekends.”
The Link Between Sleep and Diabetes
“In today’s world of constant stressors, our body is in a fight-or-flight mode all of the time, and being stressed is metabolically inefficient,” says Peter Staats, MD, chief medical officer at Truvaga and a pain medicine physician who has researched the biology of insulin resistance in type 2 diabetes. “Most of us do not meet the 7.5 hour goal, which is something we can all strive for.”
More Research Needed to Clarify the Link Between Sleep and Insulin Resistance
It’s important to point out that the study didn’t account for factors like sleep quality, sleep timing, shift work, or sleep disorders like sleep apnea that can impact insulin resistance — which all could impact the implications of the results.
“Metabolic dysfunction itself can fragment sleep and promote both short and prolonged sleep, so insulin resistance can drive abnormal sleep patterns rather than simply being a consequence of them,” Isaacs explains.
In addition, because this study was cross-sectional in design (meaning it looked at data from a single moment in time) and used self-reported sleep data, Fan recommends future research focuses on long-term studies to establish causality, and use objective sleep trackers for more precise data.
“It would also be valuable to conduct intervention trials, testing whether adjusting sleep patterns can improve metabolic health, and to study these effects in more diverse populations,” Fan says.
Tips for Improving Sleep
“We want to emphasize that sleep is not passive rest; it’s an active, essential process for metabolic health. Viewing it as a critical part of a healthy lifestyle, alongside good nutrition and physical activity, is a crucial mindset shift,” Fan says.
- Be consistent with sleep and wake times, even on weekends. “If you are sleep-deprived, a modest weekend catch-up of one to two hours is okay, but avoid sleeping in for hours, which can disrupt your rhythm,” Fan says.
- Talk to your healthcare team about your sleep style. “Be specific about your patterns, such as, ‘I typically sleep six hours on weeknights and nine hours on weekends and still feel tired.’ Also ask if your sleep habits could be affecting your weight or blood sugar, and mention any concerns like loud snoring or excessive daytime fatigue,” Fan says.
- Put your devices away before bed. “Turn off all computers and cellphones an hour before you plan on going to sleep, and disconnect from the electronic world,” Dr. Staats suggests.
- Manage evening eating habits. Staats recommends avoiding large meals before bedtime, and limiting caffeinated drinks to the morning or earlier part of the day.
- Get regular physical movement. Routine exercise, preferably in the earlier part of the day, can help you get good rest at night, Staats points out.