Kardiovaskuläre und metabolische Risikofaktoren nach der Menopause. Einfluss unterschiedlicher Trainingsinterventionen auf die körperliche Leistungsfähigkeit, das kardiovaskuläre Risikoprofil und die Mechanismen des Energiestoffwechsels der postmenopausalen Frau

The menopause is the main cardiovascular risk factor of women. The main reason for this risk is the reduction of the hormone estrogen which possesses a highly cardio- protective effect on several cardiovascular risk factors. Hence, there is an increasing risk to develop the metabolic syndrome (MetS). In the context of health policy, the development of preventive and secondary preventive interventions is of high importance.
The aims of the studies were to evaluate the prevalence of the MetS in postmenopausal women without hormone substitution and to evaluate the effects of specific training interventions on postmenopausal women with special consideration of the energy metabolism.
In the first study, the cardio-metabolic situation of 12 premenopasual (25.0 ± 3.5 years) women was compared to 12 postmenopausal women (57.7 ± 4.3 years) in a cross- sectional study design.
Parameters that were evaluated were: Baseline blood pressure ((systolic (BDsys), diastolic (BDdias)) and BDsys at 100 watt power during a bicycle ergometer test, waist circumference (BU), body weight, body-mass-index (BMI), body fat (KF), lean body mass (MA), body cell mass (BCM), baseline energy demand (REB), fasting glucose (BZ), HbA1C, triglycerides (TG), total cholesterol (G-CHOL), HDL, LDL, pulse wave velocity (PWV), augmentation index (AI@75), pulse pressure (PD), LF/HF Ratio, total power, pNN50, r-MSSD, maximum watt power (Wattmax), maximum relative watt power (Wattmax/kg KG), maximum oxygen consumption (VO2peak), watt power at defined lactate thresholds (2.0mmol/L, 2.5mmol/L, 3.0mmol/L), respiratory ratio (RQ), and lactate concentration after 10, 20 and 30 minutes of a constant load.
Statistical analyses were conducted using the unpaired t-test and the Mann-Whitney- U test.
Results revealed that the BMI was similar in both groups (p=0.444). Postmenopausal women possessed higher values in BU (p=0.003), worse values in body composition (KF; p=0.001), MA (p=0.001), BCM (p=0.001), and REB (p=0.001). The following laboratory parameters were also worse in postmenopausal women: BZ (p=0.002), HbA1c (p=0.001), G-CHOL (p=0.001), and LDL (p=0.001). Further, BDsys (p=0.014), BDdias (p=0.018), BD at 100 watt power (p=0.001), PWV (p=0.001), and AI@75
Abstract 236
(p=0.020) were higher in postmenopausal women. Heart rate variability (HRV) parameters showed a sympatho-vagal imbalance in postmenopausal women. Results of the cardio-respiratory fitness revealed that postmenopausal women possessed a lower endurance capacity compared to premenopausal women measured in the following parameters: Wattmax (p=0.001), Wattmax/kg KG (p=0.001), VO2peak (p=0.001), watt power at 2.0mmol/L (p=0,031) 2.5mmol/L (p=0.003), 3.0mmol/L (p=0.008), and at watt power corresponding to 60% of the 4mmol/L lactate threshold (p=0.005).
Postmenopausal women showed a lower fat oxidation (p=0.011) compared to the premenopausal women.
Results illustrate an altered cardio-metabolic situation in postmenopausal women that goes along with an increased risk to develop the MetS. Further, this study emphasizes the fact that it is imperative to develop specific training interventions that improve the energy metabolism and reduce the cardiovascular risk of postmenopausal women without hormonal substitution.
The differential effects of different training interventions on the cardiovascular risk and energy metabolism of postmenopausal women without hormonal substitution were evaluated in the second prospective, randomized and controlled interventional study.
49 healthy, obese postmenopausal women (56.6 ±3.7 years) were recruited for the second study. Subjects were randomly devided into three intervention groups and one control group: Endurance training group (ATG; n=12; 57.5 ± 5.9 years), interval training group (ITG; n=12; 55.6 ± 3.6 years), resistance training group (KTG; n=15; 56.8 ± 2.8 years), and a control group (KG; n=10; 55.9 ± 3.6 years). The following tests were conducted before and after the 12-week intervention in all groups: Baseline BD measurement, BD measurement at 100 watt power, measurement of BMI and BU, measurement of arterial stiffness, bioimpedance-analysis, spirometric measurement on the bicycle ergometer, venous blood sampling, 30-minute bicycle spirometric measurement at watt power corresponding 60% of the 4mmol/L lactate threshold, and estimation of the one-repetition-maximum (1RM) using specific resistance training exercises (rowing (RU), chest press (BRP), leg press (BP), abs exercises (BA), back
exercises (RÜ), leg extension (BS), leg curl (BB), shoulder press (SD), shoulder pull (SZ), adductors (AD), and abductors (AB)).
Statistical analyses were conducted using a linear model with mixed effects (LMA). Post-hoc analyses were conducted using paired t-tests and Wilcoxon test. Endurance training (AT) had the highest effect in improving VO2peak (p=0.015) and watt power at defined lactate theresholds (all p=0.001). Interval training (IT) was most effective in improving Wattmax (p=0.022), Wattmax/kg KG (p=0.026). This training had no effect on BDsys.
AT had a positive effect on fat oxidation of postmenopausal women (p=0.031). Resistance training (KT) was most effective in improving the dynamic muscle strength (1RM). Significant differences were observed in the following exercises: RU (p=0.001), BRP (p=0.001), SD (p=0.001), BS (p=0.001), and BP (0=0.001).
The different training interventions led to differences in the cardio vascular risk profile only in the following parameters: ITG: Reduction of body fat (T2 to T1; p=0.025; group effect p=0.020); KTG: Reduction of the BDsys (T2 to T1; p=0.004). In all other parameters no difference was observed.
Results confirm the positive effects of the different training interventions in postmenopausal women. AT was most effective in improving cardio-respiratory fitness, aerobic endurance capacity, and the energy metabolism of postmenopausal women. IT was more effective in improving dynamic force parameters compared to the other interventions. Future intervention studies should therefore combine elements of AT and KT.
The effect of the training interventions on cardiovascular risk factors was more moderate compared to similar studies. This might be explained by the low training volume and the low overall intervention duration. Hence, future studies should focus on the optimal training volume and optimal intervention time.