According to data from a 30-year observational study, sufficient exercise in young adulthood can effectively reduce the risk of high blood pressure in later life. However, this requires twice as much exercise as recommended by the WHO.
Elevated blood pressure is an important risk factor for the development of cardiovascular diseases. Only a few years ago, the blood pressure target values in the USA were lowered and are now below 130/80 mmHg (in Germany 135/85 mmHg). This means that about two-thirds of 55-64 year olds in the USA are affected by high blood pressure. One way to reduce the risk of arterial hypertension is regular physical activity. However, it is unclear what effect exercise at a young age has on the development of hypertension later in life. A research team from San Francisco has now investigated this.
The researchers used data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which included over 5,100 participants from 4 different regions in the USA. The mean age of the participants was 25 years, half were of African-American descent and women were slightly overrepresented in the cohort at 54%. The mean body mass index (BMI) was 23.4 kg/m2 and 56% of participants were non-smokers. Mean blood pressure at inclusion was 110/68 mmHg and 14% of participants already had arterial hypertension.
The participants in the CARDIA study were observed for 30 years and were called in for examinations a total of nine times during this time (approx. every 2-5 years). On the one hand, blood pressure was measured (3 times with short breaks in between). On the other hand, the test subjects were asked about their physical activity within the last 12 months. Important parameters were intensity and duration of the exercise units.
From the data, a score was calculated that reflected the average physical activity of a person. A score of 300 exercise units (EU) corresponded to the current guidelines of the World Health Organisation (WHO) of 150 minutes of moderate physical activity per week. At study inclusion, the average value of the participants was 360 EU, i.e. slightly more than recommended by the guidelines.
Physical activity was found to decrease in almost all participants over the course of their lives. The greatest decline was in black men, who were very physically active at age 18 (about 550 EU), but by age 60 had an activity level of only 300 EU. In contrast, white men who were similarly physically active as black men at a young age still had an average activity of 450 EU. Black women were the least physically active when they were young (about 310 EU). By the age of 60, their activity dropped to about 200 EU. White women, on the other hand, kept their activity largely stable over their lifetime at around 350 EU.
At age 60, 73% of the study participants had developed high blood pressure. Black men had the highest incidence. Using logistic regression analysis, the researchers calculated the effect of physical activity on the likelihood of developing hypertension. For example, a 100 EU lower physical activity score at age 18 was associated with a 4% higher probability of developing hypertension. Those who neglected physical activity during their lifetime also faced a higher risk. For example, a reduction in physical activity of one EU per year increased the likelihood of hypertension by 2%. These results were independent of age, sex, origin, health behaviour, pre-existing conditions, lipid profile and obesity.
Surprisingly, the study participants who followed the WHO recommendations and had an activity level of about 300 EU did not reduce their risk of hypertension. In contrast, those who exercised more than recommended early in life and in middle age were able to significantly reduce their risk of hypertension. For example, physical activity of more than 600 EU at age 18 was associated with an 18% lower risk. This is twice as much exercise as the WHO currently recommends. If these people maintained their activity over their lifetime, the risk was reduced by a further 4%.
Despite the interesting results, the study has some weaknesses. For example, the participants were only asked about their physical activity. However, many people overestimate their physical activity - an objective measurement, e.g. with the help of fitness watches, would have been more optimal. In addition, the diet of the test subjects was not recorded. Unhealthy foods can contribute to the development of high blood pressure just as much as too little exercise.
Overall, the data of the study show that regular physical activity at a young age can be an important factor in the prevention of high blood pressure in old age. People who are very physically active as young adults can build up a kind of "protective buffer" against high blood pressure. This buffer can be further strengthened by maintaining fitness in middle age, so that the risk of hypertension continues to decrease. However, the 150 minutes of moderate physical activity recommended by the WHO does not seem to be enough. Rather, twice that amount is necessary to achieve a beneficial effect. This goal can be achieved, for example, with 5 hours of easy cycling (15 km/h) or with 2.5 hours of jogging (pace 7:30 min/km) per week.
Reference:
Nagata et al. Physical Activity and Hypertension From Young Adulthood to Middle Age. AJPM. April 15, 2021