Sleeping an average of more than eight hours per night, or less than seven hours per night, appears to greatly increase the risk of developing pre-diabetes, as well as full type 2 diabetes.
It’s recommended by many medical professionals that adults sleep an average of seven to eight hours per night. Sleeping less than seven hours is generally considered under-sleeping, and has been linked to a wide range of medical (heart disease, obesity, for example) and psychological conditions. Sleeping more than the recommended amount has also been linked to health problems, though less definitively.
The current study studied 276 participants over a six year period. The most striking, general observations, was that both over and under-sleepers developed diabetes, and the associated pre-diabetic condition, insulin resistance, more than twice as often as seven-eight hour sleepers. More specifically, without adjusting for other external risk factors (such as obesity), it was seen that 20% of over and under-sleepers developed diabetes over the course of the study, compared to only seven percent of eight hour sleepers. Adjusting for external factors, it was still seen that over and under-sleepers were approximately twice as likely to develop diabetes than seven-eight hour sleepers.
This study gives further support to past research, which has associated poor sleeping habits with early death. Obesity, heart disease, and diabetes, are connected in many ways, with each being of some risk for generating the others, and all associated with increased risk of mortality. Now all have been linked to unhealthy sleep durations as well, putting further emphasis on the importance of getting seven-eight hours of nightly sleep.
Source: Defeat Diabetes Foundation: Tremblay, Angelo. Huppe, Jean-Francois. Sleep Medicine news release. April 2009.