Heart rate recovery after treadmill exercise testing is an independent predictor of stroke incidence in men with metabolic syndrome

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.

Heart rate recovery time in metabolically healthy and metabolically unhealthy obese children

BACKGROUND

Autonomic dysfunction is an emerging non-traditional cardiovascular risk factor that correlates with obesity, components of metabolic syndrome, as well as cardiorespiratory fitness. As a simple and validated index of autonomic balance, heart rate recovery (HRR) has been reported as a useful biomarker for predicting cardiovascular morbidity and mortality.

OBJECTIVES

The aim of this study was to compare HRR in metabolically healthy vs. metabolically unhealthy obese children.

METHODS

A total of 56 obese children of whom 31 had metabolic syndrome were examined. All the participants underwent the multistage submaximal cycle ergometer test and HRR was determined one minute after the test.

RESULTS

The HRR was significantly lower (18.9 ± 3.7) in a group of metabolically unhealthy obese children compared to metabolically healthy obese children (24 ± 4.1) p < 0.001. Logistic regression analysis showed that reduction in HRR was also influenced by higher BMI.

CONCLUSION

Our findings implicate the presence of the autonomic dysfunction as reflected by impaired heart rate recovery (HRR) in obese children with metabolic syndrome.

Association of exercise heart rate response and incidence of hypertension in men

OBJECTIVE

To examine the association of heart rate (HR) responses at rest, during exercise, and after exercise with incident hypertension (HTN) in men.

PARTICIPANTS AND METHODS

A total of 10,418 healthy normotensive men without abnormalities on electrocardiography or a history of myocardial infarction, stroke, cancer, or diabetes underwent a maximal exercise test and were followed up for incidence of HTN. Heart rate reserve was defined as the maximal HR minus resting HR. Heart rate recovery was defined as HR 5 minutes after the exercise test.

RESULTS

During a mean follow-up of 6 years, there were 2831 cases of HTN. Compared with men who had lower HR reserve, the risk of incident HTN was significantly lower for men with higher HR reserve (hazard ratio, 0.84; 95% CI, 0.74-0.95 for the highest quartile vs the lowest quartile of HR reserve; P=.002) when adjusted for age, baseline examination year, smoking, heavy drinking, body mass index, resting blood pressure, cholesterol and glucose levels, and cardiorespiratory fitness. Compared with men who had higher HR recovery, the risk of incident HTN was significantly lower for men with lower HR recovery (hazard ratio, 0.90; 95% CI, 0.80-0.99 for quartile 3 vs highest quartile; P=.04) after adjusting for the aforementioned confounders. However, the overall linear trend for HR recovery was not significant (P=.26).

CONCLUSION

The risk of HTN decreased in men with higher HR reserve. Therefore, HR reserve may be considered as a useful exercise parameter for predicting the risk of HTN in men.