Extremes of sleep duration increase BMI, SAT, and VAT

Not getting enough sleep does more damage than just leaving you with puffy eyes. It can cause fat to accumulate around your organs or visceral fat,

Other behaviors, besides daily food choices, could be contributing to the obesity epidemic in younger age groups.

A recent study, lead by Kristen G. Hairston of the Wake Forest University School of Medicine, shows that participants younger than 40 years of age who reported sleeping five hours or less per night had greater increases in body mass index (BMI), as well as in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) fat* accumulation. The researchers also found that getting more than eight hours of sleep on average per night has a similar -- though less pronounced effect.

The study involved 1,107 people with a mean age of 41.7 years at baseline and an age range from 18 to 81 years. Abdominal computed tomography (CT) scans and BMI obtained at a 5-year interval. Sleep duration was assessed by questionnaire at baseline and categorized as equal to or less than 5 hours, 6-7 hours, and equal to or more than 8 hours. Generalized estimating equations using linear regression models assessed the association between sleep duration and five-year fat accumulation with adjustment for age, race, gender, study site, baseline fat measure, physical activity, total calorie intake, smoking status and education.

The authors proposed that short sleep may impact fat accumulation by promoting increased caloric intake via increased hunger, or by reducing energy expenditure via altered thermoregulation and increased fatigue. Both increased caloric intake and decreased vigorous activity were observed in the short sleep group.

The findings also indicate that there's more to "fat" than what we choose to eat -- social factors such as the need to work three jobs in a bad economy -- could be causing dangerous fat deposition around vital organs.

The authors suggested that it is just as important for doctors to encourage patients to get adequate sleep as it is for them to promote a healthy diet and physical activity. This is particularly relevant when young adults make transitions involving college, marriage and childbearing, because these life stages often are associated with sleep deprivation.

Journal Reference:

Hairston KG; Bryer-Ash M; Norris JM; Haffner S; Bowden DW; Wagenknecht LE. Sleep Duration and Five-Year Abdominal Fat Accumulation in a Minority Cohort: The IRAS Family Study. SLEEP 2010;33(3):289-295.

* Visceral fat is not the fat that lies just under your skin, that type is called subcutaneous fat.

Visceral fat surrounds your vital organs, the fat is located in the abdominal cavity (stomach area).

The more visceral fat you carry around the higher your chances of developing insulin resistance (leading to Type-II diabetes), heart disease and other metabolic syndromes.

Exercise can significantly reduce the amount of visceral fat you carry around. The more exercise you do, the more of this type of dangerous fat you will lose. CLICK HERE for details.