In the Wisconsin sleep cohort study of 1024 patients, the shorter sleep durations showed reduced levels of leptin and elevated levels of ghrelin. In a study with 3000 patients, it has been found that men and women who sleep less than 5 hours have elevated body mass index (BMI). In another study that followed about 70.000 women for 16 years, there was a significant increase in body weight in those who slept 5 hours or less compared to those who slept 7–8 hours.[1][2][5]