Routinely getting too little sleep may increase a person’s visceral fat, fat that accumulates around the body’s internal organs.  Kristen G. Hairston, from Wake Forest University School of Medicine (North Carolina, USA), and colleagues studied the five-year change in visceral adipose tissue and subcutaneous adipose tissue associated with sleep duration in a group of African Americans and a group of Hispanic Americans, ages 18-81 years, enrolled in the IRAS Family Study.  In participants under age 40, the team found a clear association between averaging five hours or less of sleep each night and large increases in visceral fat.  Of the study participants under age 40, Hispanic men and black women were the largest groups to report getting such little sleep.  Additionally, the researchers found that getting more than eight hours of sleep on average per night has a similar – though less pronounced – result, and most prevalently affected Hispanic women of all ages.