(Reuters) - Lowering blood pressure below a commonly used target significantly reduced serious heart problems and cut the risk of death in adults aged 50 and older, according to preliminary results of a large U.S. government-sponsored study released on Friday.

In the study of more than 9,300 patients with hypertension, using a combination of medicines to reduce systolic pressure to a target of 120 versus 140 cut the rate of heart attacks, strokes and heart failure by almost a third and the risk of death by nearly a quarter.

"This study provides potentially life-saving information that will be useful to health care providers as they consider the best treatment options for some of their patients, particularly those over the age of 50," Dr. Gary Gibbons, director of the National Heart, Lung, and Blood Institute (NHLBI), which sponsored the study, said in a statement.

Researchers cautioned that full analysis of the results had not been completed and that medical guidelines groups must still study the data to determine if it should lead to a change in practice. They said it was not yet clear how many more people might require more intensive treatment to lower blood pressure.

Systolic blood pressure, the arterial pressure when the heart contracts, is the top number in a blood pressure reading. High blood pressure is widely considered a leading risk factor for heart disease, kidney failure and other health problems.

The vast majority of blood pressure medicines from a variety of classes are available as inexpensive generics. The classes include angiotensin receptor blockers, or ARBs, such as Novartis' Diovan, calcium channel blockers, like Pfizer's Norvasc, ACE inhibitors, including Pfizer's Altace, and diruetics, such as Merck's Hyzaar.

Doctors on a conference call to discuss the study said blood pressure of 120 over 80 was seen as desirable, but that 140/90 was a commonly used target. They also noted that there is no real consensus, which was a reason for conducting the trial.

Patients in the study, conducted between 2010 and 2013, had a mean age of 68, with 25 percent over 75, and were deemed at increased risk of heart disease or had kidney disease. It did not include patients who had a prior stroke or those with diabetes.

The intensive treatment group received an average of three blood pressure-reducing medicines, while the 140 target group was taking an average of two medicines.

While adverse side effects in the intensive treatment group were still being analyzed, researchers said, the study was stopped early when the significant benefits of intense treatment became obvious.

"Patients should talk to their doctor to determine whether this lower goal is best for their individual care," said Dr. Lawrence Fine, chief of Clinical Applications and Prevention at the NHLBI.

(Editing by Bernadette Baum and Dan Grebler)