The aim of this study was to evaluate and compare systolic blood pressure recovery and heart rate recovery (HRR) values obtained at various time intervals after maximal graded exercise treadmill testing between patients with metabolic syndrome (MS) and the controls without MS. To our knowledge, this is the first study indicating systolic blood pressure recovery (SBPR) impairment and its relations to HRR and other variables in this group of patients.
The study population included 110 patients with MS (67 men, 43 women; mean age: 46 ± 9 years) and 110 control subjects who did not meet the criteria for MS (58 men, 52 women; mean age: 44 ± 10 years). All patients were selected from nonobese, apparently healthy sedentary individuals who had the ability to perform maximum exercise testing. SBPR was assessed by calculating the ratio of systolic blood pressure (SBP) obtained in the third minute of the recovery period to either the peak-exercise SBP or the SBP in the first minute of the recovery period after graded exercise testing. HRR values were calculated by subtracting the HR at the first, second, third, fourth, and fifth minutes of the recovery period from the HR reached at peak exercise.
There was no significant difference found between the 2 groups with respect to age and sex distribution. As expected, patients with MS had higher waist circumference, fasting plasma glucose and serum triglyceride, and lower high-density lipoprotein cholesterol compared with control subjects. All HRR values calculated in the first, second, third, fourth, and fifth minutes were significantly detected lower in the MS group compared with the control group (HRR 1st: 32 ± 10 vs 36 ± 11; P = 0.009; HRR 2nd: 47 ± 10 vs 51 ± 11; P = 0.02; HRR 3rd: 53 ± 11 vs 58 ± 12; P = 0.001; HRR 4th: 57 ± 11 vs 64 ± 12; P < 0.001; HRR 5th: 60 ± 16 vs 69 ± 15; P < 0.001). In addition, calculated mean values for SBPR1 and SBPR2 were >1 in patients with MS (1.01 ± 0.2 vs 0.91 ± 0.1 and 1.01 ± 0.1 vs 0.94 ± 0.1) and these were statistically significant compared with the control group (P < 0.001 and P = 0.002, respectively). The existence of MS was found to be the only parameter that was independently and positively related to SBPR values in the study population.
Our findings suggest that only the existence of MS itself, not the presence of any MS components, is independently associated with SBPRs. We are of the opinion that significantly impaired SBPR values, in addition to the decreased HRR values observed in this group of patients, such as those with MS, may especially help identify patients with potentially increased cardiovascular risk despite normal exercise stress testing findings.