Systolic blood pressure increases sharply with age in people in Western societies. There is a lesser increase in diastolic pressure. Thus pulse pressure increases with age. Thus, instead of the usual blood pressure of 120 over 80 seen in younger individuals, with is a pulse pressure of 40, blood pressures of 160 over 90 may be seen, with a pulse pressure of 70.
The fact that the pulse pressure increases is simply an expression of the age-related decrease in arterial compliance. The vessels become stiffer and they are able to store less of the pressure energy as stretch during systole, i.e. a smaller Windkessel effect. The fact that the diastolic pressure increases as well is not primarily a function of the change in compliance of the vessel wall, but is rather due to the increased resistance of the arterial tree.
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