SBP above 180 mmHg at moderate exercise workload increases coronary heart disease risk in healthy men during 28-year follow-up

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.

Exercise Systolic Blood Pressure at Moderate Workload Is Linearly Associated With Coronary Disease Risk in Healthy Men

There is no consensus on the definition of an exaggerated increase in systolic blood pressure (SBP) during exercise. The aim was to explore a potential threshold for exercise SBP associated with increased risk of coronary heart disease in healthy men using repeated exercise testing. Two thousand fourteen healthy white male employees were recruited into the Oslo Ischemia Study during early 1970s. At follow-up 7 years later, 1392 men were still considered healthy. A bicycle exercise test at 100 W workload was performed at both visits. Cox regression analyses were performed with increasing cutoff levels of peak exercise SBP at 100 W workload (SBP100W) from 160 mm Hg to 200 mm Hg, adjusted for cardiovascular risk factors and physical fitness. Participants with SBP100W below cutoff level at both baseline and first follow-up were compared with participants with SBP100W equal to or above cutoff level at both visits. Compared with participants with SBP100W below all cutoff levels between 165 and 195 mm Hg, coronary heart disease risk was increased among participants with SBP100W equal to or above cutoff at all levels. There was no evidence of a distinct threshold level for coronary heart disease risk, and the relation between SBP100W and coronary heart disease appears linear. When investigating exercise SBP at moderate workload measured at 2 exercise tests in healthy middle-aged white men, there is increasing risk of coronary heart disease with increasing exercise SBP independent of SBP at rest. The association is linear from the low range of exercise SBP, and there is no sign of a distinct threshold level for increased coronary disease risk.