Sleep deprivation has been linked to health problems such as obesity and high blood pressure, negative mood and behavior and decreased productivity.Studies have found a relationship between the quantity and quality of one's sleep and many health problems. For example, insufficient sleep affects growth hormone secretion that is linked to obesity; as the amount of hormone secretion decreases, the chance for weight gain increases. Blood pressure usually falls during the sleep cycle, however, interrupted sleep can adversely affect this normal decline, leading to hypertension and cardiovascular problems. Research has also shown that insufficient sleep impairs the body's ability to use insulin, which can lead to the onset of diabetes. More and more scientific studies are showing correlations between poor and insufficient sleep and disease.