The U-Shaped Association Between Physical Activity and Cardiovascular Mortality
High levels of physical activity in individuals with the greatest risk of cardiovascular disease may well be worse than moderate physical activity when it comes to mortality. We might theorize that this is the outcome of putting an excessive level of stress on a weakened, damaged system. The study noted here is supportive of other similar studies that suggest that physical activity at the high end of the range is detrimental over the long term, in comparison to more moderate levels. Though in this context, "moderate" is probably twice the present recommendation of 150 minutes per week, which is itself more moderate exercise than most of the population undertakes.
The beneficial effect of moderate physical activity (PA) on morbidity and mortality has been observed in the general population. However, the ideal intensity of PA for improving cardiovascular longevity in Japanese general population is uncertain. The aim of this study was to investigate the relationship between the PA and cardiovascular mortality in the general population. This longitudinal cohort study included 1,826 apparently healthy subjects who participated in a community-based health checkup.
There were 31 cardiovascular deaths during 10-year follow-up. Subjects were divided into 4 groups based on the quartiles of PA (low, mild, moderate and high). Kaplan-Meier analysis and multivariate Cox proportional hazard analysis demonstrated that the most favorable cardiovascular prognosis was observed in subjects with moderate PA followed by those with mild PA. High PA as well as low PA were associated with higher cardiovascular mortality compared with mild and moderate PA. Noteworthy, in subjects with high PA, Cox hazard analysis revealed that previous cardiovascular disease, smoking, brain natriuretic peptide levels, and Framingham risk score were associated with cardiovascular mortality.
The results suggest a U-shaped association between cardiovascular mortality and PA. Mild to moderate PA was associated with favorable cardiovascular outcomes in the Japanese general population. High PA might be associated with poor cardiovascular outcomes in subjects with a history of heart disease and high coronary risk factors.
Of course if we have an extreme strain like in professional sports it is harmful. However, I am really surprised that a run of the mill office drone can have too much physical activity even if we are talking about a fitness freak.
The J curve to exercise dose discussed above is contrasted below showing 90% reduction in CVD risk with 1300 minutes/wk of moderate exercise measured by an accelerometer. If you survive 1-2hrs/day then more is better. https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003809
To me, the cause is soft plaques, whose uncalcified caps are broken during high BP and pulse during exercise. Reducing soft plaques thru diet and meds, and evaluating them before a change to more dosage of exercise is best. https://www.texasheart.org/heart-health/heart-information-center/topics/vulnerable-