Effects of Exercise Training Intensity on Cardiometabolic Risk in Women with the Metabolic Syndrome with or without Hypertension

Abstract

The metabolic syndrome (MS) and hypertension (HTN) are both associated with elevated cardiometabolic risk including insulin resistance. PURPOSE: We examined the effects of intensity of aerobic exercise training on resting blood pressure and insulin sensitivity in normotensive (NT) and hypertensive (HT) abdominally obese women with the MS. METHODS: Twenty-six abdominaly obsese women [mean (SD); age 51.0 (8.7) y, ht 165.8 (5.6) cm, wt 94.0 (18.1) kg, % fat 44.1 (4.3)] who met the IDF criteria for the MS were randomly assigned to one-of-three 16-week conditions: (i) No Exercise Training (NOET): (7) maintained existing levels of physical activity, (ii) Low-Intensity Exercise Training (LIET): (10) exercised 5x/week at an intensity < lactate threshold (LT) (iii) High-Intensity Exercise Training (HIET): (9) exercised 3x/week at an intensity > LT and 2x/week < LT. Exercise time was adjusted to maintain caloric expenditure (400 kcal/session). Each subject completed a VO2 Peak treadmill test, seated blood pressure, and fasting laboratories. Group differences were examined using Mixed-Effects ANO VA. RESULTS: At baseline, there were no significant differences between conditions for VO2 Peak, SBP, DBP, insulin, or QUICKI (all p-values > 0.05) [SBP: 129+16 mm Hg, DBP: 78 + 10 mm Hg, VO2 Peak: 38.5 + 6 ml/kg-FFM/min, insulin: 13 + 7 uU/ml, SBP: 0.323 + .022 (mean + SD, pooled)]. Exercise training reduced SBP, with LIET resulting in an 11.2 mmHg reduction in SBP (−3.9 mmHg for NT and - 16.4 mmHg for HT) (p = 0.002), which was superior to NOET (+ 4.8 mmHg for NT, - 1.0 mmHg for HT, p = 0.023) and HIET (−0.75 mmHg for NT, −3.3 mmHg for HT, p = 0.056). QUICKI was significantly elevated in the LIET subjects with HT (p < 0.05). There were no significant changes in DBP, or fasting insulin. The reduction in SBP was related to increased QUICKI (r=−0.57). CONCLUSION: We conclude that exercise training reduces SBP in an intensity dependent manner, with LIET resulting in the greatest reduction in SBP, particularly in those women with HT. The reduction in SBP appears to be related to improved insulin sensitivity. These data suggest that lower intensity exercise (individualized to the lactate threshold) may have utiltiy for designing exercise intervention programs for lowering blood pressure, particularly in abdominally obese women with elevated blood pressure.