101 Facts About Ageing #13: Blood Pressure Increases With Age

As Daniel Patrick Moynihan, an American sociologist, politician, and diplomat once said: “Everyone is entitled to his own opinion, but not his own facts”. And we wholeheartedly agree. A shared set of facts is the first step to building a better world with longevity for all. In that spirit, we are creating a series that covers 101 indisputable facts about ageing, health and longevity.

Blood pressure measurements have two components: systolic blood pressure (the force of the blood against the walls of the arteries while the ventricles of the heart contract) and diastolic blood pressure (the blood pressure when the heart is relaxing). Both tend to increase until around the age of 50, after which systolic pressure continues to rise while diastolic pressure falls. On average, males have a higher systolic and diastolic pressure at most ages when compared with females.

During ageing, the probability of developing hypertension (a harmful increase in blood pressure) becomes higher. A systolic blood pressure of 140mmHg and a diastolic blood pressure of 90mmHg (noted as 140/90) or higher is generally considered to be hypertension. The risk of developing hypertension is partly genetic (twin studies suggest that blood pressure is 30-50% hereditary). Lifestyle factors such as smoking, diet, exercise and alcohol consumption also affect the risk of developing hypertension. Hypertension itself rarely has symptoms but increases the risk of serious diseases like heart disease, stroke, kidney disease and dementia. According to the WHO, about 1.13 billion people worldwide have hypertension, two thirds of whom live in low/middle-income countries.

The changes in blood pressure with age are mostly caused by changes in blood vessel stiffness. When the heart contracts, the walls of the arteries stretch to accommodate the blood as it is pumped out by the heart, then spring back to their original position as the heart relaxes, which helps maintain blood pressure as the heart prepares for the next beat. With age, the walls of the arteries become less elastic and less able to accommodate blood during each beat of the heart. This results not only in an increase in systolic blood pressure, but also a decrease in diastolic pressure because the artery walls don’t spring back to position as strongly as before. However, up until around age 50, diastolic pressure still increases because the resistance of peripheral blood vessels (the veins and arteries outside of the chest and abdomen) increases with age.