Inadequate sleep may increase the risk of high blood pressure, according to a study made by Columbia University in New York. The study, conducted by a team of researchers led by James E. Gangwisch, was based on the data collected from 4,810 people (ages 32 to 86) who did not have high blood pressure at the beginning of the research. Hypertension was diagnosed in 647 subjects during the follow-up period 1982 to 1992. For the subjects in the age group 32 to 59 years, sleeping less than 6 hours per night, doubled with almost 50% their risk of developing hypertension. 24% of people in the mentioned age group developed the disease, in comparison to only 12% of those who slept 7 or 8 hours. Research also showed that people who slept 5 or fewer hours a night also exercised less and were more likely to have a higher body mass index. "Sleep allows the heart to slow down and blood pressure to drop for a significant part of the day. However, people who sleep for only short durations raise their average 24-hour blood pressure and heart rate. This may set up the cardiovascular system to operate at an elevated pressure," Gangwisch stated. As for lowering the risk, another study showed that a diet rich in fruits and veggies and low on dairy products or saturated fats can decrease the risk. Doctors who made the second study also recommended exercising, lowering daily sodium intake to less than 2,300 mg and not abusing alcohol.