Novel insights into stroke risk beyond resting and maximal bicycle exercise systolic blood pressure

OBJECTIVE: Previous research has shown an association between moderate workload exercise blood pressure (BP) and coronary disease, whereas maximal exercise BP is associated with stroke. We aimed to investigate the association between the increase in BP during maximal exercise and the long-term risk of stroke in healthy, middle-aged men. METHODS: Two thousand and fourteen men were included in the Oslo Ischemia Study in the 1970s. In the present study, we examined baseline data of the 1392 participants who remained healthy and performed bicycle exercise tests both at baseline and 7 years later. Cox proportional hazard was used to assess the risk of stroke in participants divided into quartiles based on the difference between resting and maximal workload SBP (ΔSBP) at baseline, adjusting for resting BP, age, smoking, serum cholesterol and physical fitness. Follow-up was until the first ischemic or hemorrhagic stroke through 35 years. RESULTS: There were 195 incident strokes; 174 (89%) were ischemic. In univariate analyses, there were significant positive correlations between age, resting SBP, resting DBP and SBP at moderate and maximal workload, and risk of stroke. In the multivariate analysis, there was a 2.6-fold (P < 0.0001) increase in risk of stroke in ΔSBP quartile 4 (ΔSBP > 99 mmHg) compared with ΔSBP quartile 2 (ΔSBP 73-85 mmHg), which had the lowest risk of stroke. ΔSBP quartile 1 had a 1.7-fold (P = 0.02) increased risk compared with quartile 2, suggesting a J-shaped association to stroke risk. CONCLUSION: Stroke risk increased with increasing difference between resting and maximal exercise SBP, independent of BP at rest, suggesting that an exaggerated BP response to physical exercise may be an independent predictor of stroke.