Tight or loose cuffs during blood pressure measurement can have an impact on the results of the blood pressure measurement and can affect the accuracy of the blood pressure values measured by the sphygmomanometer. Studies have shown that a blood pressure cuff that is tied too loosely or too tightly can affect blood pressure values by as much as 10 to 20 mm Hg. When the cuff is tied too tightly when measuring blood pressure, the arterial vessels receive more pressure before the cuff is inflated and pressurized, which can cause the measured blood pressure to be relatively lower than the true value. If the cuff is tied too loosely, the measured blood pressure may be relatively higher than the true value. Therefore, in order to measure blood pressure accurately, the cuff must be loosely tied so that there is just enough space between the arm and the cuff for about two fingers to fit.