Fatigue isn’t the only consequence of insufficient sleep: new research shows it may also cause high blood pressure. Sleep deprivation—even just a few hours worth—boosts activity in the sympathetic nervous system, which regulates our stress response. That, in turn, can lead to hypertension in adults, shows the study in the June 8 issue of the Archives of Internal Medicine, in which participants slept an average of six hours per night. For every hour of sleep lost, the chance of developing high blood pressure was shown to increase 37 per cent over five years. Men, especially African American males, had the highest levels of hypertension. Future research will focus on how sleep duration and quality can help prevent high blood pressure.