Abstract

BACKGROUND

Obesity and aging are associated with increased arterial stiffness as indicated by an increased pulse-wave velocity (PWV). We evaluated the independent and combined effects on PWV and body composition of a hypocaloric diet and low-intensity resistance exercise training (LIRET) with slow movement.

METHODS

Forty-one postmenopausal women (mean age, 54±6 years; body mass index (BMI), 33.8±0.5kg/m2) were randomly assigned to LIRET (n = 14), diet (n = 13), or diet + LIRET (n = 14) for 12 weeks. The women’s PWV, mean arterial pressure (MAP), body composition by dual-en ergy x-ray absorptiometry (DXA), and plasma adipokine and insulin levels were measured before and after the interventions.

RESULTS

Body weight (P = 0.0001), trunk-fat mass (FM, P = 0.0001), and the serum concentration of leptin (P = 0.02 and P = 0.004) decreased similarly with diet and diet + LIRET, but not with LIRET alone. Leg lean mass (LM) decreased (P = 0.02) with diet, but did not change with diet + LIRET or with LIRET alone. Leg muscle strength increased similarly with LIRET (P = 0.001) and diet + LIRET (P = 0.0001), but did not change with diet alone. Brachial–ankle PWV (baPWV) decreased with diet (P = 0.04) and diet + LIRET (P = 0.01), whereas femoral–ankle PWV (legPWV) decreased only with diet (P = 0.01). Mean arterial pressure (MAP) decreased after LIRET (P = 0.03), diet (P = 0.04), and diet + LIRET (P = 0.004). Carotid–femoral PWV, serum adiponectin concentration, and insulin were not significantly affected by the interventions examined in the study. The reductions in baPWV and legPWV were correlated with one another (r = 0.73, P = 0.0001), and the reductions in legPWV and trunk FM were also correlated with one another (r = 0.36, P = 0.03).

CONCLUSIONS

A hypocaloric diet decreases baPWV mainly by reducing legPWV, and this reduction is related to the loss of truncal fat. Although LIRET alone does not affect PWV or body composition, LIRET combined with diet improves baPWV and muscle strength while preventing loss of lean body mass in obese postmenopausal women.

Obesity and hypertension are important risk factors for cardiovascular disease (CVD), the leading cause of death in postmenopausal women.1 Aging and obesity are associated with increased arterial stiffness (pulse-wave velocity, PWV),2–4 an independent predictor of systolic hypertension,5 and with cardiovascular mortality in hypertensive adults.6 Aging and the main components of the metabolic syndrome, abdominal obesity and hypertension, increase peripheral arterial stiffness, especially in women.2,7,8 In postmenopausal women, central adiposity is associated with increased aortic PWV (aPWV) and leg PWV (legPWV),8 the main components of brachial–ankle PWV (baPWV),9 explaining the progressive increase in baPWV after menopause.10

It is well established that interventions designed to produce weight loss reduce blood pressure (BP) in obese adults.11–13 However, the impact of a hypocaloric diet on PWV is not clear. Some studies have reported reductions in aPWV after 12 weeks of such a diet in overweight and obese adults.11,14–16 In contrast, Samaras et al.13 reported that 12 weeks of a hypocaloric diet failed to decrease aPWV in obese adults. Apparently, the increase in arterial elasticity induced by weight loss occurs earlier in peripheral than in central arteries.12,17 Thus, it is possible that a short-term diet would decrease legPWV and hence baPWV rather than decreasing aPWV. Because leptin determines the relationship between PWV and abdominal adiposity,18 a possible mechanism responsible for the reduction in PWV with diet could be changes in adipokines and insulin levels.19–21 Diet-induced weight loss is accompanied by loss of lean mass (LM),11,16,22 preferentially from the legs,23 which may aggravate the age-related loss in muscle mass known as sarcopenia. Although high-intensity resistance exercise training (HIRET) can attenuate the diet-induced loss of muscle mass19 or leg LM,23 there is evidence that HIRET may increase aPWV, legPWV, and baPWV.24,25 However, it appears that the adverse effect of HIRET on baPWV occurs with upper-body but not lower-body exercises25 and with concentric rather than eccentric contractions.26 Alternatively, low-intensity resistance exercise training (LIRET) with slow movement can improve muscle mass27 and baPWV in young healthy adults.28 Because a negative association exists between leg LM and PWV in older women,29 maintaining or improving leg LM with LIRET during diet-induced weight loss may positively influence arterial function. Therefore, we hypothesized that the combination of diet and LIRET would produce greater improvements in PWV and adiposity than would either intervention alone in obese postmenopausal women. We also hypothesized that LIRET would improve muscle strength and attenuate the loss of LM induced by diet.

METHODS

Subjects

Forty-five women volunteered for a randomized, parallel-design study to evaluate the independent and combined effects on PWV and body composition of a hypocaloric diet and LIRET with slow movement. The subjects were overweight or obese (body mass index (BMI) ≥ 25kg/m2), postmeno pausal (≥ 1 year without menstruation), sedentary (< 60 minutes of aerobic exercise/week and no resistance training during the past 6 months), and nonsmokers. They were screened for chronic diseases with a medical-history questionnaire and were excluded if they had diabetes or cardiovascular disease or both. All of the subjects gave written informed consent to participating in the study. The study protocol was approved by The Florida State University Human Subject Committee (2011.5485) and registered in Clinicaltrial.gov (NCT01371370).

Study design

Women were randomly assigned to diet or LIRET alone or to diet + LIRET for 12 weeks. The subjects had their BP, PWV, muscle strength, and body composition measured and had blood samples drawn at baseline and at the end of the study for measurement of leptin, adiponectin, and insulin. Specimens for cardiovascular and blood measurements were collected after an overnight fast and between 48 and 72 hours after a lack of moderate or intense physical activity.

Subjects were asked to refrain from caffeine, alcohol, or prescribed medication for 24 hours before each visit. Measurements at each visit were made in the morning at the same time of day in a quiet, temperature-controlled room (23±1 °C). Subjects rested in the supine position for at least 10 minutes before data collection. Subjects were instructed not to make changes in their medications, diet, or exercise habits during the study, other than those required by the assigned intervention.

Interventions

Subjects in the LIRET group underwent 3 supervised exercise sessions per week on nonconsecutive days. Four exercises (leg press, leg extension, leg flexion, and calf raise) were performed on variable-resistance machines (MedX, Ocala, FL). Women performed 2 sets of exercises involving 18–22 repetitions of each exercise, to the point of volitional fatigue, during the first 2 weeks of the study, and 3 sets of such exercises thereafter. Resistance was increased to maintain a protocol of ~20 repetitions/set as a bout of resistance exercise because this range of repetitions has been found to acutely decrease legPWV30and BP.31 The speed of contraction was controlled with a metronome and concentric and eccentric contractions were performed in phases lasting 2 seconds and 3 seconds each, respectively. Compliance was assessed by attendance at supervised exercise sessions.

Subjects in the diet group were enrolled in a commercial weight-loss program (Nutrisystem, Fort Washington, PA) at no cost to themselves. The program includes portion-controlled foods, which are supplemented with recommended conventional foods (e.g. fruits, vegetables, dairy items) to complete a structured meal plan that provides ~1,250 kcal/day. The subjects’ diet included breakfast, lunch, and dinner entrees plus 1 snack per day. Participants purchased their daily choice of 4 vegetable, 3 lean protein or low-fat dairy, 3 fruit, and 1 fat servings. Beyond being given an initial briefing on the diet, participants received no individual or group counseling sessions. The meal plans were structured to provide energy from carbohydrate (55%–60%), fat (20%–25%), and protein (20%–25%). Participants completed a 3-day food record during the last week of the study. Subjects in the diet + LIRET group participated in the diet and LIRET programs described for the other two groups.

Arterial function

Pulse-wave velocity, brachial systolic BP (SBP), and diastolic BP (DBP) were measured with an an automated device for measuring PWV and ABI (VP-2000, Omron Healthcare, Vernon Hills, IL). Blood pressure cuffs were wrapped around both the subject’s arms and ankles while tonometers were positioned over the right carotid and the femoral arteries to obtain measurements of the carotid–femoral PWV (aPWV), femoral–ankle PWV (legPWV), and baPWV. Transit time was automatically determined from the time delay between the feet of the pulse waves and the R-wave of an electrocradiogram. The distance between the common carotid and femoral arteries was measured with a nonelastic tape measure and the brachial–ankle and femoral–ankle distances were calculated automatically by the device used for measuring PWV on the basis of the subject’s height.32 The values of aPWV, legPWV, and baPWV were calculated from measurements of transit time and the distance between 2 recording sites.32 Mean arterial pressure (MAP) was calculated as DBP + 0.45 (SBP–DBP).

Body composition

Height and body weight were measured to the nearest 0.5cm and 0.1kg, respectively, with a stadiometer and beam scale, respectively. Body mass index was calculated as weight in kg/height in meters squared. Total body fat mass (FM), trunk FM, total LM, arm LM, and leg LM were measured from whole-body dual-energy X-ray absorptiometry (DXA) scans (GE Lunar DPX-IQ, Madison, WI).

Muscle strength

Muscle strength was assessed with the eight-repetition maximum (8RM) test, defined as the maximum weight that can be moved eight times through a full range of motion, for the leg press exercise. Relative strength was calculated as leg strength divided by leg LM.

Biomarkers

Blood samples (~10ml) were obtained by venipuncture to determine leptin, adiponectin, and insulin levels with commercially available enzyme-linked immunosorbent assay kits for leptin and adiponectin (R&D Systems, Minneapolis, MN) and for insulin (IBL International, Hamburg, Germany)). The sensitivities of the assays were 7.8 pg/ml, 0.246ng/ml, and 1.76 μIU/ml for leptin, adiponectin, and insulin, respectively. Intra- and interassay coefficients of variation were 1.2% and 8.4%, 3.2% and 8.8%, and 2.3% and 5.4% for leptin, adiponectin, and insulin, respectively.

Statistical analysis

Data were examined for normality with the Shapiro–Wilk test. On the basis of prior data,14,28 it was calculated that 14 subjects per group would provide 80% power (two-sided alpha = 0.05) to detect an 8% reduction in baPWV. One-way analysis of variance (ANOVA) was used to examine possible group differences at baseline. The effect of the interventions over time was evaluated with a 3 × 2 ANOVA with repeated measures (group (diet × LIRET × diet + LIRET) × time (before × after 12 weeks)). When a significant group × time interaction and/or time effect was identified, between-group and within-group differences were examined with Tukey’s test and paired t-tests, respectively. Pearson’s correlations were calculated to evaluate the relationship between changes in body composition and changes in PWV and biomarkers. A value of P < 0.05 was considered statistically significant. Data analysis was done with SPSS version 18.0 (SPSS, Chicago, IL). Data are presented as mean ± SE.

RESULTS

Four subjects dropped out the study for personal reasons unrelated to diet or LIRET. Data are presented for 14, 13, and 14 subjects in the LIRET, diet, and diet + LIRET groups, respectively. Women taking prescribed medications had stable doses of these medications for at least 1 year (Table 1), and no changes in this were reported during the study. Attendance at the exercise sessions in the study was greater than 86% and 89% in the LIRET and diet + LIRET groups, respectively.

Table 1.

Medication use at baseline in the three study-intervention groups

Medication LIRET Diet Diet + LIRET 
HRT 
ACE inhibitors 
Cholesterol-lowering drugs 
Medication LIRET Diet Diet + LIRET 
HRT 
ACE inhibitors 
Cholesterol-lowering drugs 

Values for medication use are number of participants.

Abbreviations: ACE, angiotensin converting enzyme; HRT, transdermal hormone replacement therapy; LIRET, low-intensity resistance exercise training.

Anthropometry and body composition

Subjects were overweight (n = 3) or had class I (n = 22), II (n = 13), or III (n = 3) obesity as defined by BMI (33.8±0.5kg/m2). There were no group differences in any variable at baseline (Tables 2 and 3). Table 2 shows body composition and leg muscle strength. There were group × time interactions for weight (P = 0.04), total FM (P = 0.04), and trunk FM (P = 0.01), for which there were decreases after both of the study diet interventions as compared with a lack of change after LIRET. Body weight was reduced after the diet (5.5±1.0kg, P = 0.0001) and diet + LIRET (4.9±1.0kg, P = 0.0001) interventions. Total FM and trunk FM were reduced after the diet (P = 0.001 and P = 0.0001) and diet + LIRET (P = 0.0001 and P = 0.0001) interventions. The decrease in total LM after the diet (P = 0.03) intervention did not differ from that with LIRET and diet + LIRET. There were significant group × time interactions for leg LM (P =0.04), absolute strength (P = 0.0001), and relative strength (P = 0.001), with leg LM decreasing after diet (P = 0.02) as compared with LIRET (P = 0.04), and absolute and relative leg muscle strength increasing after LIRET (P = 0.001 and P = 0.008) and diet + LIRET (P = 0.0001 and P = 0.0001) as compared with the lack of a change after the diet intervention alone.

Table 2.

Baseline characteristics, body composition, and muscle strength before and after study interventions

 LIRET  Diet  Diet + LIRET    
Variable Before After P* Before After P* Before After P* P** 2 
Age, years 54±1 54±1  54±1 
Height, m 1.66±0.02 1.62±0.02 1.63±0.02 
BMI, kg/m2 32.6±1.0  34.8±1.2  32.7±1.1 
Body weight, kg 88.4±4.6 86.9±4.3 0.08  89.0±4.4 83.4±4.6a 0.0001  86.7±2.7 81.9±2.5a 0.0001 0.04 0.22 
Total fat mass, kg 41.8±3.2 40.2±2.7 0.12  44.1±2.9 39.7±3.1a 0.001  41.9±2.0 37.5±2.0a 0.0001 0.04 0.19 
Trunk fat mass, kg 20.2±1.8 20.0±1.6 0.06  23.5±1.7 20.8±1.5a 0.0001  22.1±1.1 19.6±1.2a 0.0001 0.01 0.23 
Total lean mass, kg 44.0±2.1 44.2±2.3 0.71  43.6±1.6 42.3±1.8 0.03  42.4±1.3 41.6±1.2 0.12 0.19 0.09 
Arm lean mass, kg  4.6±0.2  4.7±0.3 0.70 4.8±0.3  4.7±0.3 0.22 4.6±0.2  4.5±0.2 0.32 0.19 0.09 
Leg lean mass, kg 15.8±0.9 16.1±1.1 0.40  15.6±0.8 14.6±0.9a 0.02  14.9±0.6 14.6±0.5 0.14 0.04 0.20 
Absolute strength, kg  113±3  141±8c 0.001  118±8  111±8 0.12  104±5  129±5c 0.0001  0.0001 0.47 
Relative strength, r  7.3±0.4  8.8±0.8b 0.008 7.6±0.6 7.3 ±.6 0.47 7.1±0.4  8.8±0.3b 0.0001 0.001 0.37 
 LIRET  Diet  Diet + LIRET    
Variable Before After P* Before After P* Before After P* P** 2 
Age, years 54±1 54±1  54±1 
Height, m 1.66±0.02 1.62±0.02 1.63±0.02 
BMI, kg/m2 32.6±1.0  34.8±1.2  32.7±1.1 
Body weight, kg 88.4±4.6 86.9±4.3 0.08  89.0±4.4 83.4±4.6a 0.0001  86.7±2.7 81.9±2.5a 0.0001 0.04 0.22 
Total fat mass, kg 41.8±3.2 40.2±2.7 0.12  44.1±2.9 39.7±3.1a 0.001  41.9±2.0 37.5±2.0a 0.0001 0.04 0.19 
Trunk fat mass, kg 20.2±1.8 20.0±1.6 0.06  23.5±1.7 20.8±1.5a 0.0001  22.1±1.1 19.6±1.2a 0.0001 0.01 0.23 
Total lean mass, kg 44.0±2.1 44.2±2.3 0.71  43.6±1.6 42.3±1.8 0.03  42.4±1.3 41.6±1.2 0.12 0.19 0.09 
Arm lean mass, kg  4.6±0.2  4.7±0.3 0.70 4.8±0.3  4.7±0.3 0.22 4.6±0.2  4.5±0.2 0.32 0.19 0.09 
Leg lean mass, kg 15.8±0.9 16.1±1.1 0.40  15.6±0.8 14.6±0.9a 0.02  14.9±0.6 14.6±0.5 0.14 0.04 0.20 
Absolute strength, kg  113±3  141±8c 0.001  118±8  111±8 0.12  104±5  129±5c 0.0001  0.0001 0.47 
Relative strength, r  7.3±0.4  8.8±0.8b 0.008 7.6±0.6 7.3 ±.6 0.47 7.1±0.4  8.8±0.3b 0.0001 0.001 0.37 

Values are mean ± SE.

Abbreviations: FM, fat mass; LIRET, low-intensity resistance exercise training; LM, lean mass; Pη2, partial eta-squared (size effect); r, ratio between leg strength and leg LM.

*Within-group difference by paired t-test. **Analysis of variance group × time interaction.

aP < 0.05 different from LIRET, bP<0.01, cP<0.001, different from diet (between-group differences by Tukey’s post hoc test).

Table 3.

Arterial stiffness, blood pressure, adiponectin concentrations, and insulin levels before and after study interventions

 LIRET  Diet  Diet + LIRET    
Variable Before After P* Before After P* Before After P* P** Pη2 
aPWV, cm/s 1,187±67 1,146±48 0.55 1,175±94 1,125±66 0.29  1,181±42  1,130±30 0.26 0.99 0.001 
legPWV, cm/s 1,002±24 1,032±18 0.06 1,017±33  941±19bc 0.01  1,032±18  1,017±19 0.17 0.004 0.35 
baPWV, cm/s 1,355±48 1,368±29 0.73 1,388±96  1,261±50a 0.04  1,395±35  1,335±27 0.01 0.04 0.15 
SBP, mm Hg 132±4 125±2 0.03 128±3 121±2 0.02 133±3  124±3 .004 0.68 0.02 
DBP, mm Hg 82±3 77±2 0.06 77±2 72±2 0.21  79±2  74±2 0.01 0.65 0.02 
MAP, mm Hg 105±3 99±2 0.03 99±2 94±2 0.04  104±2  96±3 .004 0.65 0.02 
Leptin, ng/ml 43.6±5.2 46.2±6.6 0.58  54.4±5.7  41.1±5.7a 0.02  50.3±8.2 38.7±6.5a .004 0.03 0.22 
Adipo, μg/ml 11.4±1.4 10.2±1.3 0.11  10.7±1.6  10.6±1.4 0.68  8.9±1.4  9.4±1.5 0.73 0.52 0.04 
Insulin, mU/l 12.8±2.0 12.5±1.4 0.84  18.2±1.7  18.6±2.9 0.85  18.4±2.8  17.8±1.7 0.84 0.95 0.003 
 LIRET  Diet  Diet + LIRET    
Variable Before After P* Before After P* Before After P* P** Pη2 
aPWV, cm/s 1,187±67 1,146±48 0.55 1,175±94 1,125±66 0.29  1,181±42  1,130±30 0.26 0.99 0.001 
legPWV, cm/s 1,002±24 1,032±18 0.06 1,017±33  941±19bc 0.01  1,032±18  1,017±19 0.17 0.004 0.35 
baPWV, cm/s 1,355±48 1,368±29 0.73 1,388±96  1,261±50a 0.04  1,395±35  1,335±27 0.01 0.04 0.15 
SBP, mm Hg 132±4 125±2 0.03 128±3 121±2 0.02 133±3  124±3 .004 0.68 0.02 
DBP, mm Hg 82±3 77±2 0.06 77±2 72±2 0.21  79±2  74±2 0.01 0.65 0.02 
MAP, mm Hg 105±3 99±2 0.03 99±2 94±2 0.04  104±2  96±3 .004 0.65 0.02 
Leptin, ng/ml 43.6±5.2 46.2±6.6 0.58  54.4±5.7  41.1±5.7a 0.02  50.3±8.2 38.7±6.5a .004 0.03 0.22 
Adipo, μg/ml 11.4±1.4 10.2±1.3 0.11  10.7±1.6  10.6±1.4 0.68  8.9±1.4  9.4±1.5 0.73 0.52 0.04 
Insulin, mU/l 12.8±2.0 12.5±1.4 0.84  18.2±1.7  18.6±2.9 0.85  18.4±2.8  17.8±1.7 0.84 0.95 0.003 

Values are mean ± SE.

Abbreviations: Adipo, adiponectin; aPWV, aortic pulse wave velocity; baPWV, brachial–anklePWV; DBP, diastolic blood pressure; LIRET, low-intensity resistance exercise training; MAP, mean arterial pressure; Pη2, partial eta-squared (size effect); SBP, systolic blood pressure

*Within-group difference by paired t-test. **ANOVA group × time interaction.

aP < 0.05 and bP < 0.01 different from LIRET; cP < 0.05 different from diet + LIRET (between-group difference by Tukey’s post hoc test).

Arterial function

Pulse-wave velocity and BP before and after the three interventions are shown in Table 3. No statistically significant decrease in aPWV occurred after any of the interventions (Figure 1a). There were group × time interactions for legPWV (P = 0.004) and baPWV (P = 0.04). LegPWV decreased after diet (P = 0.01), but not after LIRET and diet + LIRET. The change in legPWV after diet was significant as compared with the change after LIRET (P = 0.0001) and diet + LIRET (P = 0.04) (Figure 1b). Although there was a decrease in baPWV after diet (P = 0.048) and diet + LIRET P = 0.009), only the change after diet was significant as compared with LIRET (P = 0.04) (Figure 1c). There was no significant group × time interaction for BP. Systolic BP and MAP decreased after LIRET (P = 0.03 for both), diet (P = 0.02 and P = 0.04), and diet + LIRET (P = 0.004 for both). Brachial DBP decreased after diet+LIRET (P = 0.008), but not after LIRET (P = 0.06) and diet (P = 0.21).

Figure 1.

Changes in aortic (a), leg (b), and brachial–ankle (c) arterial stiffness after 12 weeks of low-intensity resistance exercise training (LIRET), diet, and diet + LIRET.Abbreviations are: PWV, pulse wave velocity; aPWV, aortic PWV; legPWV, leg PWV; baPWV, brachial–ankle PWV. Values are mean ± SE. *P = 0.04, †P = 0.01different from before intervention (paired t-test). aP = 0.04 and bP = 0.0001 different from LIRET; cP = 0.04 different from diet + LIRET (Tukey’s post hoc test).

Figure 1.

Changes in aortic (a), leg (b), and brachial–ankle (c) arterial stiffness after 12 weeks of low-intensity resistance exercise training (LIRET), diet, and diet + LIRET.Abbreviations are: PWV, pulse wave velocity; aPWV, aortic PWV; legPWV, leg PWV; baPWV, brachial–ankle PWV. Values are mean ± SE. *P = 0.04, †P = 0.01different from before intervention (paired t-test). aP = 0.04 and bP = 0.0001 different from LIRET; cP = 0.04 different from diet + LIRET (Tukey’s post hoc test).

Blood biochemistry

There was a group × time interaction for leptin (P = 0.03), where leptin decreased after both diet (P = 0.02) and diet + LIRET (P = 0.004) as compared with LIRET (Table 3). Adiponectin and insulin levels did not change significantly in any group (Table 3).

Correlations

The change in baPWV was correlated with changes in legPWV (r = 0.73, P = 0.0001) and aPWV (r = 0.64, P = 0.0001). The decrease in legPWV was correlated with the decrease in trunk FM (r = 0.36, P = 0.03). There was no significant correlation between changes in legPWV and leg LM. The decrease in leptin levels was correlated with decreases in body weight (r = 0.55, P = 0.002) and total FM (r = 0.35, P = 0.05).

DISCUSSION

We examined two interventions that individually and combined with one another would potentially reduce arterial stiffness and improve body composition. We used a prepackaged structured meal program and an exercise program consisting of four leg exercises at low-intensity that requires approximately 30 minutes per session. The major findings of our study indicate that 12 weeks of diet or LIRET or both have no adverse effect on aPWV. However, diet alone or combined with LIRET can decrease body weight, total FM, and trunk FM concurrently with improvements in baPWV. We also show that LIRET does not affect adiposity and PWV, but that it decreases BP and prevents the loss of total LM and leg LM induced by diet in obese postmenopausal women.

Both of the diet interventions examined in our study caused a modest weight loss of ~5.1kg (5.8%), which was due primarily to a reduction in body FM in the trunk. Our data show that despite a reduction in adiposity after diet and diet + LIRET, the ~51cm/s reduction in aPWV with these interventions was not statistically significant. In accord with our findings, Samaras et al.13 observed similar nonsignificant reductions in aPWV (50cm/s) and body weight (~6kg) after 12 weeks of a hypocaloric diet in obese adults. In contrast, previous studies have reported a decrease in aPWV of from 61cm/sec to 187cm/s after 12 weeks of diet-induced weight loss (~6 to 8kg) in adults who were overweight or had class I obesity.11,14,15 Dengo et al.11 demonstrated that the reduction in aPWV was associated with the magnitude of weight loss in middle-aged and older adults. Because a difference in aPWV of 40–70cm/s exists in obese as compared with nonobese individuals,4,33 the reduction in aPWV observed after diet and diet + LIRET in our study may have a positive influence on cardiovascular function in obese postmenopausal women.

Although baPWV includes aPWV and legPWV, it has been considered a measure of central arterial stiffness because it is highly correlated with aPWV, and both baPWV and aPWV have similar associations with cardiovascular risk factors.9,32,34 We showed that legPWV decreased significantly with diet alone (~72cm/s), whereas the reduction in legPWV with diet + LIRET was minimal (~15cm/s). Previous studies have reported improvements in peripheral arterial elasticity after body-weight reduction,12.22 but to the best of our knowledge, the effect of diet on legPWV and baPWV has not been reported. Since legPWV is a main determinant of baPWV,9 there was a significant decrease in baPWV with diet (~126cm/s). In addition, there was a small but significant decrease in baPWV after diet + LIRET (~60cm/s). It is possible that the concurrent decreases in aPWV and legPWV may have contributed to reducing baPWV in the intervention consisting of diet + LIRET. Our findings indicate that there is an early effect of diet on legPWV that influences baPWV, a marker of central arterial stiffness.9 Therefore, diet with and without LIRET may be recommended to attenuate the progressive increase in baPWV observed following menopause.10

Our data show that neither adiposity nor PWV were affected by LIRET in obese postmenopausal women. In accord with our findings, previous studies have shown that neither whole-body nor leg HIRET affects either aPWV in elderly normotensive adults35.36 or baPWV in young adults.25 On the other hand, a recent study found that whole-body HIRET increased aPWV and legPWV in middle-aged adults with prehypertension or hypertension.24 It is important to note that our subjects had similar risk factors to those in the study conducted by Collier et al.24 However, our leg LIRET intervention, which was of longer duration and lower intensity than in the previous study, did not have a deleterious effect on aPWV, legPWV, or baPWV.24 Although the small increase in legPWV after LIRET alone was not statistically significant, LIRET may have attenuated the diet-induced decrease in legPWV in the diet + LIRET intervention. We found no correlation between reductions in baPWV and BP (SBP and MAP), as previously shown in middle-aged and older adults after 12 weeks of a hypocaloric diet.11 Thus, the present findings may indicate that the decreases in baPWV with diet and diet + LIRET are not determined by the distending effect of BP on the arterial wall.

A main concern associated with a hypocaloric diet is the loss of DXA-measured LM.11 occurs in the legs.23 Our data show that 12 weeks of diet reduced total LM (~1.2kg) and leg LM (~0.7kg) in obese women. Straznicky et al.37 reported a similar loss of total LM after 12 weeks of diet alone and diet + aerobic exercise training in obese adults. In agreement with the findings in the present study, Anton et al.38 found no increase in leg LM after 13-weeks of HIRET alone in middle-aged adults. In a previous study,23 HIRET attenuated the significant loss of leg LM (~0.9kg) observed in obese older adults. We demonstrated for the first time that LIRET is an effective countermeasure for the negative effects of a hypocaloric diet on leg LM. Importantly, leg muscle strength increased similarly in both the LIRET-only and diet + LIRET interventions in our study. Because sarcopenia, specifically as a reduction in leg LM,2 and muscle strength are negatively associated with baPWV,39 our findings may support the use of LIRET to prevent loss of LM and improve leg muscle strength and baPWV in obese postmenopausal women undertaking a dietary weight-loss intervention. The decrease in leptin in our study was similar with both the diet and diet + LIRET interventions. Reductions in body weight and total FM were positively correlated with changes in leptin. In accord with our data, past studies have reported decreases in leptin levels4,20,21 without an effect on adiponectin13,20 or insulin levels following weight loss.13,17 Indeed, leptin but not insulin,4 adiponectin, or C-reactive protein are related to aPWV, legPWV,8 and baPWV.40 Increased abdominal adiposity has been positively associated with baPWV,40 and with legPWV8 in women. It is likely that in our study a reduced concentration of leptin may have influenced the decrease in legPWV through reductions in FM, which occurred primarily in the trunk.

The present study has several limitations. It included obese postmenopausal women with prehypertension or stage 1 hypertension. Whether our findings remain true for men, nonobese, or normotensive individuals is unknown. The duration of LIRET in the study was 12 weeks, and a longer intervention may be needed to elicit increases in LM detectable by DXA in postmenopausal women.41 Another limitation of our study is that it did not have a nonexercise control group. However, because LIRET did not affect PWV or body composition, it provided a control group for the study. Additionally, a relatively small sample size may have limited the effect of weight loss on aPWV and correlations between body composition and PWV.

In conclusion, our study demonstrates that a hypocaloric diet with and without LIRET results in similar decreases in FM and baPWV. Although LIRET does not improve LM or reduce PWV, the addition of LIRET to diet prevents the loss of LM and improves muscle strength in obese postmenopausal women. Our data demonstrate the benefits of adding LIRET to a weight-loss intervention in obese postmenopausal women.

DISCLOSURE

Dr. Daggy works for Nutrisystem, Inc., in addition to being an adjunct faculty member at The Florida State University. The other authors declare no conflict of interest.

ACKNOWLEDGMENTS

We extend our gratitude to David Thomas for his technical expertise. This study was supported by Nutrisystem Inc. Clinicaltrial.gov register, NCT01371370.

REFERENCES

1.
Roger
VL
Go
AS
Lloyd-Jones
DM
Benjamin
EJ
Berry
JD
Borden
WB
Bravata
DM
Dai
S
Ford
ES
Fox
CS
Fullerton
HJ
Gillespie
C
Hailpern
SM
Heit
JA
Howard
VJ
Kissela
BM
Kittner
SJ
Lackland
DT
Lichtman
JH
Lisabeth
LD
Makuc
DM
Marcus
GM
Marelli
A
Matchar
DB
Moy
CS
Mozaffarian
D
Mussolino
ME
Nichol
G
Paynter
NP
Soliman
EZ
Sorlie
PD
Sotoodehnia
N
Turan
TN
Virani
SS
Wong
ND
Woo
D
Turner
MB
.
Heart disease and stroke statistics—2012 update: a report from the American Heart Association
.
Circulation
 
2012
;
125
:
e2
e220
.
2.
Snijder
MB
Henry
RM
Visser
M
Dekker
JM
Seidell
JC
Ferreira
I
Bouter
LM
Yudkin
JS
Westerhof
N
Stehouwer
CD
.
Regional body composition as a determinant of arterial stiffness in the elderly: The Hoorn Study
.
J Hypertens
 
2004
;
22
:
2339
2347
.
3.
Lebrun
CE
van der Schouw
YT
Bak
AA
de Jong
FH
Pols
HA
Grobbee
DE
Lamberts
SW
Bots
ML
.
Arterial stiffness in postmenopausal women: determinants of pulse wave velocity
.
J Hypertens
 
2002
;
20
:
2165
2172
.
4.
Rider
OJ
Tayal
U
Francis
JM
Ali
MK
Robinson
MR
Byrne
JP
Clarke
K
Neubauer
S
.
The effect of obesity and weight loss on aortic pulse wave velocity as assessed by magnetic resonance imaging
.
Obesity (Silver Spring)
 
2010
;
18
:
2311
2316
.
5.
Najjar
SS
Scuteri
A
Shetty
V
Wright
JG
Muller
DC
Fleg
JL
Spurgeon
HP
Ferrucci
L
Lakatta
EG
.
Pulse wave velocity is an independent predictor of the longitudinal increase in systolic blood pressure and of incident hypertension in the Baltimore Longitudinal Study of Aging
.
J Am Coll Cardiol
 
2008
;
51
:
1377
1383
.
6.
Laurent
S
Boutouyrie
P
Asmar
R
Gautier
I
Laloux
B
Guize
L
Ducimetiere
P
Benetos
A
.
Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients
.
Hypertension
 
2001
;
37
:
1236
1241
.
7.
Henry
RM
Ferreira
I
Dekker
JM
Nijpels
G
Scheffer
PG
Stehouwer
CD
.
The metabolic syndrome in elderly individuals is associated with greater muscular, but not elastic arterial stiffness, independent of low-grade inflammation, endothelial dysfunction or insulin resistance--The Hoorn Study
.
J Hum Hypertens
 
2009
;
23
:
718
727
.
8.
Park
JS
Nam
JS
Cho
MH
Yoo
JS
Ahn
CW
Jee
SH
Lee
HS
Cha
BS
Kim
KR
Lee
HC
.
Insulin resistance independently influences arterial stiffness in normoglycemic normotensive postmenopausal women
.
Menopause
 
2010
;
17
:
779
784
.
9.
Sugawara
J
Hayashi
K
Yokoi
T
Cortez-Cooper
MY
DeVan
AE
Anton
MA
Tanaka
H
.
Brachial-ankle pulse wave velocity: an index of central arterial stiffness?
J Hum Hypertens
 
2005
;
19
:
401
406
.
10.
Zaydun
G
Tomiyama
H
Hashimoto
H
Arai
T
Koji
Y
Yambe
M
Motobe
K
Hori
S
Yamashina
A
.
Menopause is an independent factor augmenting the age-related increase in arterial stiffness in the early postmenopausal phase
.
Atherosclerosis
 
2006
;
184
:
137
142
.
11.
Dengo
AL
Dennis
EA
Orr
JS
Marinik
EL
Ehrlich
E
Davy
BM
Davy
KP
.
Arterial destiffening with weight loss in overweight and obese middle-aged and older adults
.
Hypertension
 
2010
;
55
:
855
861
.
12.
Shargorodsky
M
Fleed
A
Boaz
M
Gavish
D
Zimlichman
R
.
The effect of a rapid weight loss induced by laparoscopic adjustable gastric banding on arterial stiffness, metabolic and inflammatory parameters in patients with morbid obesity
.
Int J Obes (Lond)
 
2006
;
30
:
1632
1638
.
13.
Samaras
K
Viardot
A
Lee
PN
Jenkins
A
Botelho
NK
Bakopanos
A
Lord
RV
Hayward
CS
.
Reduced arterial stiffness after weight loss in obese type 2 diabetes and impaired glucose tolerance: the role of immune cell activation and insulin resistance
.
Diab Vasc Dis Res
 
2012
; Apr 25. [Epub ahead of print]
14.
Miyaki
A
Maeda
S
Yoshizawa
M
Misono
M
Saito
Y
Sasai
H
Endo
T
Nakata
Y
Tanaka
K
Ajisaka
R
.
Effect of weight reduction with dietary intervention on arterial distensibility and endothelial function in obese men
.
Angiology
 
2009
;
60
:
351
357
.
15.
Clifton
PM
Keogh
JB
Foster
PR
Noakes
M
.
Effect of weight loss on inflammatory and endothelial markers and FMD using two low-fat diets
.
Int J Obes (Lond)
 
2005
;
29
:
1445
1451
.
16.
Brinkworth
GD
Noakes
M
Buckley
JD
Clifton
PM
.
Weight loss improves heart rate recovery in overweight and obese men with features of the metabolic syndrome
.
Am Heart J
 
2006
;
152
:
693.e1
6
.
17.
Goldberg
Y
Boaz
M
Matas
Z
Goldberg
I
Shargorodsky
M
.
Weight loss induced by nutritional and exercise intervention decreases arterial stiffness in obese subjects
.
Clin Nutr
 
2009
;
28
:
21
25
.
18.
Windham
BG
Griswold
ME
Farasat
SM
Ling
SM
Carlson
O
Egan
JM
Ferrucci
L
Najjar
SS
.
Influence of leptin, adiponectin, and resistin on the association between abdominal adiposity and arterial stiffness
.
Am J Hypertens
 
2010
;
23
:
501
507
.
19.
Janssen
I
Fortier
A
Hudson
R
Ross
R
.
Effects of an energy-restrictive diet with or without exercise on abdominal fat, intermuscular fat, and metabolic risk factors in obese women
.
Diabetes Care
 
2002
;
25
:
431
438
.
20.
Giannopoulou
I
Fernhall
B
Carhart
R
Weinstock
RS
Baynard
T
Figueroa
A
Kanaley
JA
.
Effects of diet and/or exercise on the adipocytokine and inflammatory cytokine levels of postmenopausal women with type 2 diabetes
.
Metabolism
 
2005
;
54
:
866
875
.
21.
Bradley
U
Spence
M
Courtney
CH
McKinley
MC
Ennis
CN
McCance
DR
McEneny
J
Bell
PM
Young
IS
Hunter
SJ
.
Low-fat versus low-carbohydrate weight reduction diets: effects on weight loss, insulin resistance, and cardiovascular risk: a randomized control trial
.
Diabetes
 
2009
;
58
:
2741
2748
.
22.
Dengel
DR
Kelly
AS
Olson
TP
Kaiser
DR
Dengel
JL
Bank
AJ
.
Effects of weight loss on insulin sensitivity and arterial stiffness in overweight adults
.
Metabolism
 
2006
;
55
:
907
911
.
23.
Frimel
TN
Sinacore
DR
Villareal
DT
.
Exercise attenuates the weight-loss-induced reduction in muscle mass in frail obese older adults
.
Med Sci Sports Exerc
 
2008
;
40
:
1213
1219
.
24.
Collier
SR
Kanaley
JA
Carhart
R
Frechette
V
Jr
Tobin
MM
Hall
AK
Luckenbaugh
AN
Fernhall
B
.
Effect of 4 weeks of aerobic or resistance exercise training on arterial stiffness, blood flow and blood pressure in pre- and stage-1 hypertensives
.
J Hum Hypertens
 
2008
;
22
:
678
686
.
25.
Okamoto
T
Masuhara
M
Ikuta
K
.
Upper but not lower limb resistance training increases arterial stiffness in humans
.
Eur J Appl Physiol
 
2009
;
107
:
127
134
.
26.
Okamoto
T
Masuhara
M
Ikuta
K
.
Effects of eccentric and concentric resistance training on arterial stiffness
.
J Hum Hypertens
 
2006
;
20
:
348
354
.
27.
Tanimoto
M
Ishii
N
.
Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men
.
J Appl Physiol
 
2006
;
100
:
1150
1157
.
28.
Okamoto
T
Masuhara
M
Ikuta
K
.
Effects of low-intensity resistance training with slow lifting and lowering on vascular function
.
J Hum Hypertens
 
2008
;
22
:
509
511
.
29.
Abbatecola
AM
Chiodini
P
Gallo
C
Lakatta
E
Sutton-Tyrrell
K
Tylavsky
FA
Goodpaster
B
de Rekeneire
N
Schwartz
AV
Paolisso
G
Harris
T
.
Pulse wave velocity is associated with muscle mass decline: Health ABC study
.
Age (Dordr)
 
2012
;
34
:
469
478
.
30.
Heffernan
KS
Rossow
L
Jae
SY
Shokunbi
HG
Gibson
EM
Fernhall
B
.
Effect of single-leg resistance exercise on regional arterial stiffness
.
Eur J Appl Physiol
 
2006
;
98
:
185
190
.
31.
Melo
CM
Alencar Filho
AC
Tinucci
T
Mion
D
Forjaz
CL.
Jr
Postexercise hypotension induced by low-intensity resistance exercise in hypertensive women receiving captopril
.
Blood Press Monit
 
2006
;
11
:
183
189
.
32.
Yamashina
A
Tomiyama
H
Takeda
K
Tsuda
H
Arai
T
Hirose
K
Koji
Y
Hori
S
Yamamoto
Y
.
Validity, reproducibility, and clinical significance of noninvasive brachial- ankle pulse wave velocity measurement
.
Hypertens Res
 
2002
;
25
:
359
364
.
33.
Wildman
RP
Mackey
RH
Bostom
A
Thompson
T
Sutton-Tyrrell
K
.
Measures of obesity are associated with vascular stiffness in young and older adults
.
Hypertension
 
2003
;
42
:
468
473
.
34.
Tanaka
H
Munakata
M
Kawano
Y
Ohishi
M
Shoji
T
Sugawara
J
Tomiyama
H
Yamashina
A
Yasuda
H
Sawayama
T
Ozawa
T
.
Comparison between carotid-femoral and brachial-ankle pulse wave velocity as measures of arterial stiffness
.
J Hypertens
 
2009
;
27
:
2022
2027
.
35.
Maeda
S
Otsuki
T
Iemitsu
M
Kamioka
M
Sugawara
J
Kuno
S
Ajisaka
R
Tanaka
H
.
Effects of leg resistance training on arterial function in older men
.
Br J Sports Med
 
2006
;
40
:
867
869
.
36.
Cortez-Cooper
MY
Anton
MM
Devan
AE
Neidre
DB
Cook
JN
Tanaka
H
.
The effects of strength training on central arterial compliance in middle-aged and older adults
.
Eur J Cardiovasc Prev Rehabil
 
2008
;
15
:
149
155
.
37.
Straznicky
NE
Lambert
EA
Nestel
PJ
McGrane
MT
Dawood
T
Schlaich
MP
Masuo
K
Eikelis
N
de Courten
B
Mariani
JA
Esler
MD
Socratous
F
Chopra
R
Sari
CI
Paul
E
Lambert
GW
.
Sympathetic neural adaptation to hypocaloric diet with or without exercise training in obese metabolic syndrome subjects
.
Diabetes
 
2010
;
59
:
71
79
.
38.
Anton
MM
Cortez-Cooper
M
Devan
AE
Neidre
D
Cook
JN
Tanaka
H
.
Resistance training increases basal limb blood flow and vascular conductance in aging humans
.
J Appl Physiol
 
2006
;
101
:
1351
1355
.
39.
Sanada
K
Miyachi
M
Tanimoto
M
Yamamoto
K
Murakami
H
Okumura
S
Gando
Y
Suzuki
K
Tabata
I
Higuchi
M
.
A cross-sectional study of sarcopenia in Japanese men and women: reference values and association with cardiovascular risk factors
.
Eur J Appl Physiol
 
2010
;
110
:
56
65
.
40.
Lee
M
Choh
AC
Demerath
EW
Towne
B
Siervogel
RM
Czerwinski
SA
.
Associations between trunk, leg and total body adiposity with arterial stiffness
.
Am J Hypertens
 
2012
;
25
:
1131
1137
.
41.
Figueroa
A
Going
SB
Milliken
LA
Blew
RM
Sharp
S
Teixeira
PJ
Lohman
TG
.
Effects of exercise training and hormone replacement therapy on lean and fat mass in postmenopausal women
.
J Gerontol A Biol Sci Med Sci
 
2003
;
58
:
266
270
.