Cross-national analysis of 70,849 participants found that moderate-to-vigorous physical activity delivered the strongest mortality protection among individuals taking hypertension medication, compared to those with normal blood pressure or untreated high blood pressure. US participants had higher treatment rates (29.9% vs 11.7%) and lower average blood pressure than UK participants, yet paradoxically experienced higher cardiovascular mortality rates. The study revealed that treated hypertensive patients with low activity levels (<10.7 minutes daily) faced dramatically steeper survival declines, dropping to 74% survival by year eight versus 91% in normotensive individuals. This finding challenges conventional assumptions about blood pressure management effectiveness and highlights exercise as a critical therapeutic complement. The research suggests that pharmaceutical intervention alone may be insufficient without lifestyle modification, particularly physical activity. However, as an unreviewed preprint, these results require peer validation before clinical application. The cross-sectional design also limits causal inference about whether exercise directly improves outcomes in medicated patients or whether healthier individuals are more likely to maintain both medication adherence and active lifestyles. This represents confirmatory evidence strengthening the exercise-as-medicine paradigm specifically for hypertensive populations.