It has long been known that the difference in blood pressure between two hands in a person is associated with a deterioration in health, but how and how exactly remained a mystery. British scientists from the University of Exeter tried to solve it by analyzing 24 global studies on this topic and bringing together health data of almost 53,827 people from different countries in Europe, Africa, Asia and the United States. The researchers looked at the difference in blood pressure in both hands for each participant and the number of deaths, heart attacks and strokes among them over more than 10 years. As a result, the British found that the greater the difference in pressure between the arms, the higher the risk of stroke, cardiovascular disease and death from them. Experts concluded that a difference of one millimeter of mercury increases the risk of death, cardiovascular disease, stroke and death by one percent. Prior to that, it was believed that the threshold difference between the pressure readings in the left and right hands is 15 millimeters of mercury. A new study has shown that the upper limit of the norm still needs to be considered a difference of 10 millimeters of mercury. Such indicators can indicate narrowing and stiffness of the arteries, which affects blood flow. Scientists believe that their findings will be useful for practical application in medicine and they need to be quickly implemented into medical practice.