The nation's leading heart experts on Monday issued new guidelines for high blood pressure that mean tens of millions more Americans will meet the criteria for the condition. Under the guidelines ... the number of men under age 45 with a diagnosis of high blood pressure will triple, and the prevalence among women under age 45 will double. The number of adults with high blood pressure, or hypertension, will rise to 103 million from 72 million under the previous standard. The number of people who are new candidates for drug treatment will rise ... by an estimated 4.2 million people. To reach the goals others may have to take more drugs or increase the dosages. The change is due largely to convincing data from a federal study published in 2015. That study, called Sprint, explored whether markedly lower blood pressure in older people - lower than researchers had ever tried to establish - might be both achievable and beneficial. In participants who were assigned to get their systolic pressures below 120, the incidence of heart attacks, heart failure and strokes fell by a third, and the risk of death fell by nearly a quarter. But more intensive drug treatment in so many more patients may increase rates of kidney disease. In the Sprint trial, the incidence of acute kidney injury was twice as high in the group receiving drugs to reduce their systolic pressure to 120. Lifestyle changes like diet and exercise can help many patients lower blood pressure. But many of the newly diagnosed are likely to wind up on drugs.