There is ample research to support an alarming association between short sleep duration and metabolic disorders. Insufficient sleep affects hormonal, behavioral, and genetic mechanisms. However, recent emerging evidence is showing how excessive sleep duration can have a remarkably similar negative effect on health including associations with obesity and type 2 diabetes.

At least half of all adults either get too little sleep (less than 6 h sleep per day) or too much sleep (over 9 h sleep per day). Too little and too much sleep has been associated with higher risk of obesity (31.3% and 38.1% respectively) and type 2 diabetes mellitus (9% increased risk for each 1-h less sleep than 7 hours of sleep and 14% increased risk for each 1-h more sleep than 9 hours).

How does too little sleep increase risk for obesity and type 2 diabetes?

  • Fat tissue biopsies show increased insulin resistance state from seven healthy young adults following 4 d of
  • Increased brain activation to food stimuli including drive to eat

What are the associations between too much sleep increase risk for obesity and type 2 diabetes?

  • Assuming long sleep duration is due to poor quality of sleep: Light and poor quality of sleep can result in impaired insulin sensitivity, reduced circulation of satiety-enhancing gut hormone glucagon-like peptide 1 (GLP-1) and decreased fullness scores resulting in increased daytime and nighttime food intake and snacking in long-duration which contributes to a positive energy balance and finally, weight gain.
  • According to research it appears that those who sleep too much are less engaged in leisure time physical activity, such as regular exercise. Thus, a sedentary lifestyle combined with less moderate to vigorous physical activity may contribute to obesity and T2DM among long sleepers.
  • Research shows that long-duration sleepers tend to consume less dietary fiber which can contribute to increased risk of metabolic disorders.
  • Long duration sleepers seem to exhibit increased alcohol consumption compared to those with more optimal sleep duration. Alcohol is a well-known risk factor for upper airway collapse, thereby favoring the occurrence of sleep apneas, which may not only compromise sleep quality which is known to increase risk for obesity and T2DM.

So essentially long duration sleep results in impaired whole-body energy metabolism through multiple possible compounding mechanisms, including poor sleep quality, sedentary lifestyle and unhealthy dietary choices.


Tan, T., Chapman, C., Cedernaes, J., Benedict, B. (2018) β€˜Association between long sleep duration and increased risk of obesity and type 2 diabetes: A review of possible mechanisms’, Sleep Medicine Reviews, 40, pp. 127 – 134