Effect of 1-h moderate-intensity aerobic exercise on intramyocellular lipids in obese men before and after a lifestyle intervention.

Intramyocellular lipids (IMCL) are depleted in response to an acute bout of exercise in lean endurance-trained individuals; however, it is unclear whether changes in IMCL content are also seen in response to acute and chronic exercise in obese individuals. We used magnetic resonance spectroscopy in 18 obese men and 5 normal-weight controls to assess IMCL content before and after an hour of cycling at the intensity corresponding with each participant's maximal whole-body rate of fat oxidation (Fatmax). Fatmax was determined via indirect calorimetry during a graded exercise test on a cycle ergometer. The same outcome measures were reassessed in the obese group after a 16-week lifestyle intervention comprising dietary calorie restriction and exercise training. At baseline, IMCL content decreased in response to 1 h of cycling at Fatmax in controls (2.8 ± 0.4 to 2.0 ± 0.3 A.U., -39%, p = 0.02), but not in obese (5.4 ± 2.1 vs. 5.2 ± 2.2 A.U., p = 0.42). The lifestyle intervention lead to weight loss (-10.0 ± 5.4 kg, p < 0.001), improvements in maximal aerobic power (+5.2 ± 3.4 mL/(kg·min)), maximal fat oxidation rate (+0.19 ± 0.22 g/min), and a 29% decrease in homeostasis model assessment score (all p < 0.05). However, when the 1 h of cycling at Fatmax was repeated after the lifestyle intervention, there remained no observable change in IMCL (4.6 ± 1.8 vs. 4.6 ± 1.9 A.U., p = 0.92). In summary, there was no IMCL depletion in response to 1 h of cycling at moderate intensity either before or after the lifestyle intervention in obese men. An effective lifestyle intervention including moderate-intensity exercise training did not impact rate of utilisation of IMCL during acute exercise in obese men.

Whole-body substrate metabolism is associated with disease severity in patients with non-alcoholic fatty liver disease.

OBJECTIVES: In non-alcoholic fatty liver disease (NAFLD), hepatic steatosis is intricately linked with a number of metabolic alterations. We studied substrate utilisation in NAFLD during basal, insulin-stimulated and exercise conditions, and correlated these outcomes with disease severity. METHODS: 20 patients with NAFLD (mean ± SD body mass index (BMI) 34.1 ± 6.7 kg/m(2)) and 15 healthy controls (BMI 23.4 ± 2.7 kg/m(2)) were assessed. Respiratory quotient (RQ), whole-body fat (Fat ox) and carbohydrate (CHO ox) oxidation rates were determined by indirect calorimetry in three conditions: basal (resting and fasted), insulin-stimulated (hyperinsulinaemic-euglycaemic clamp) and exercise (cycling at an intensity to elicit maximal Fat ox). Severity of disease and steatosis were determined by liver histology, hepatic Fat ox from plasma ß-hydroxybutyrate concentrations, aerobic fitness expressed as VO2 peak, and visceral adipose tissue (VAT) measured by computed tomography. RESULTS: Within the overweight/obese NAFLD cohort, basal RQ correlated positively with steatosis (r=0.57, p=0.01) and was higher (indicating smaller contribution of Fat ox to energy expenditure) in patients with NAFLD activity score (NAS) ≥ 5 vs <5 (p=0.008). Both results were independent of VAT, % body fat and BMI. Compared with the lean control group, patients with NAFLD had lower basal whole-body Fat ox (1.2 ± 0.3 vs 1.5 ± 0.4 mg/kg FFM/min, p=0.024) and lower basal hepatic Fat ox (ie, ß-hydroxybutyrate, p=0.004). During exercise, they achieved lower maximal Fat ox (2.5 ± 1.4 vs. 5.8 ± 3.7 mg/kg FFM/min, p=0.002) and lower VO2 peak (p<0.001) than controls. Fat ox during exercise was not associated with disease severity (p=0.79). CONCLUSIONS: Overweight/obese patients with NAFLD had reduced hepatic Fat ox and reduced whole-body Fat ox under basal and exercise conditions. There was an inverse relationship between ability to oxidise fat in basal conditions and histological features of NAFLD including severity of steatosis and NAS.

Effect of exercise training combined with phytoestrogens on adipokines and C-reactive protein in postmenopausal women: a randomized trial.

Phytoestrogens and training could be effective to reduce cardiovascular and type 2 diabetes mellitus risk factors in postmenopausal women. Nevertheless, the impact of their combination on adipokines and systemic inflammation was never investigated. The objective was to verify if 6 months of mixed training combined with phytoestrogens could have an additional effect on adipokine levels and systemic inflammation in obese postmenopausal women. Fifty-two obese women aged between 50 and 70 years were randomly assigned to (1) exercise with placebo (EX + PL; n = 25) or (2) exercise with phytoestrogens (EX + PHY; n = 27). Body weight, waist circumference, fat mass, and lean body mass (dual-energy x-ray absorptiometry) were assessed. Fasting plasma glucose and insulin, adiponectin, leptin, and C-reactive protein (CRP) levels were obtained after a 12-hour overnight fast. Total energy intake was measured with a 3-day dietary record. All measurements were performed before and after the 6-month intervention. Although energy intake remained unchanged, body composition was improved in all women (all Ps < .02). Plasma CRP and leptin levels decreased in both groups similarly (all Ps < .03), whereas plasma adiponectin and insulin did not change with exercise combined with placebo or phytoestrogens. Correlation analyses showed that homeostasis model assessment of insulin resistance (r = -0.58, P = .02) and fasting insulin levels (r = -0.42, P = .02) at baseline were both correlated with changes in leptin levels. Baseline fasting glucose (r = -0.36, P = .03) and adiponectin (r = 0.45, P = .005) levels were associated with changes in CRP concentrations. Although mixed exercise program combined with phytoestrogens does not seem to provide any additional effect, mixed training improves systemic inflammation and leptin concentrations in obese postmenopausal women.

Is fat mass distribution related to impaired mobility in older men and women? Nutrition as a determinant of successful aging: the Quebec longitudinal study.

It is established that a high level of fat mass (FM) is related to mobility impairment in older adults. However, FM distribution has received very little attention. In this study, 904 well-functioning older adults aged between 68 and 82 years old were recruited to examine the association between waist circumference, trunk FM, leg FM, and mobility. The results show that waist circumference was the only measure of body fat distribution independently associated with mobility (p ≤ .001). Therefore, the use of objective measures of FM distribution may not be necessary to examine the impact of FM distribution on mobility.

Effects of soya isoflavones and exercise on body composition and clinical risk factors of cardiovascular diseases in overweight postmenopausal women: a 6-month double-blind controlled trial.

Results from a pilot project indicate that isoflavones and exercise could have an additive effect on body composition and clinical risk factors of CVD in postmenopausal women. The objective of the present study was to assess the combined effect of exercise and isoflavones in overweight-to-obese postmenopausal women. In this double-blind randomised controlled trial, 100 overweight-to-obese (BMI 29·9 (sd 3·2) kg/m2) postmenopausal women were assigned to four groups: (1) placebo (PLA); (2) isoflavones (ISO); (3) exercise and placebo (Ex+PLA); (4) exercise and isoflavones (Ex+ISO). The supplementation contained 70 mg/d of isoflavones. Exercise consisted of three weekly sessions of resistance training and aerobics. Outcome measures included fat mass (FM), lean body mass (LBM), bone mineral density, lipid profile, fasting glucose, fasting insulin and insulin resistance (homeostasis assessment model). The main effects of exercise were observed for total FM (P = 0·02), FM% (P < 0·01), trunk FM% (P = 0·05), arm FM% (P < 0·01), leg FM% (P = 0·02), arm LBM (P < 0·01), leg LBM (P = 0·02) and C-reactive protein (P < 0·01). A main effect was detected for isoflavones in improving leg FM% (P = 0·05). No interactions were observed between isoflavones and exercise. In conclusion, it was observed that 6 months of exercise brought favourable changes in total FM, FM% and LBM in overweight postmenopausal women. No synergistic effects were observed between exercise and isoflavones. However, isoflavones could have a beneficial effect on leg FM%.

Predicting energy expenditure in elders with the metabolic cost of activities.

INTRODUCTION: Measuring free-living energy expenditure in aging human is a considerable challenge. The objective of this study was to predict total energy expenditure (TEE) in elders by combining the metabolic cost of activities and accelerometer outputs. METHODS: Seventeen elders (7 women, 10 men) aged 60 to 78 yr were recruited. Body composition was measured by dual x-ray absorptiometry. Doubly labeled water was used as the criterion standard to measure TEE on a 7-d time frame. During the same period, participants wore a uniaxial accelerometer (Caltrac) to estimate TEE. Resting metabolic rate and metabolic costs of sitting, standing, and walking (1, 3, and 5 km·h(-1)) were measured by indirect calorimetry. RESULTS: There was no correlation between Caltrac's outputs and doubly labeled water measurement of TEE. The best predictors of TEE were fat-free mass, the metabolic cost of standing, and the metabolic cost of walking at 3 km·h(-1) (r = 0.78, P < 0.01). CONCLUSIONS: Our results suggest that TEE may be estimated with good accuracy using fat-free mass, the cost of standing still, and the cost of walking at 3 km·h(-1). These predictors are easy to measure in older adults. Further work is needed to confirm our findings and develop prediction equation with these parameters.

Accelerometer-based wireless body area network to estimate intensity of therapy in post-acute rehabilitation.

BACKGROUND: It has been suggested that there is a dose-response relationship between the amount of therapy and functional recovery in post-acute rehabilitation care. To this day, only the total time of therapy has been investigated as a potential determinant of this dose-response relationship because of methodological and measurement challenges. The primary objective of this study was to compare time and motion measures during real life physical therapy with estimates of active time (i.e. the time during which a patient is active physically) obtained with a wireless body area network (WBAN) of 3D accelerometer modules positioned at the hip, wrist and ankle. The secondary objective was to assess the differences in estimates of active time when using a single accelerometer module positioned at the hip. METHODS: Five patients (77.4 +/- 5.2 y) with 4 different admission diagnoses (stroke, lower limb fracture, amputation and immobilization syndrome) were recruited in a post-acute rehabilitation center and observed during their physical therapy sessions throughout their stay. Active time was recorded by a trained observer using a continuous time and motion analysis program running on a Tablet-PC. Two WBAN configurations were used: 1) three accelerometer modules located at the hip, wrist and ankle (M3) and 2) one accelerometer located at the hip (M1). Acceleration signals from the WBANs were synchronized with the observations. Estimates of active time were computed based on the temporal density of the acceleration signals. RESULTS: A total of 62 physical therapy sessions were observed. Strong associations were found between WBANs estimates of active time and time and motion measures of active time. For the combined sessions, the intraclass correlation coefficient (ICC) was 0.93 (P < or = 0.001) for M3 and 0.79 (P < or = 0.001) for M1. The mean percentage of differences between observation measures and estimates from the WBAN of active time was -8.7% +/- 2.0% using data from M3 and -16.4% +/- 10.4% using data from M1. CONCLUSION: WBANs estimates of active time compare favorably with results from observation-based time and motion measures. While the investigation on the association between active time and outcomes of rehabilitation needs to be studied in a larger scale study, the use of an accelerometer-based WBAN to measure active time is a promising approach that offers a better overall precision than methods relying on work sampling. Depending on the accuracy needed, the use of a single accelerometer module positioned on the hip may still be an interesting alternative to using multiple modules.

User-based motion sensing and fuzzy logic for automated fall detection in older adults.

More than one third of community-dwelling older adults and up to 60% of nursing home residents fall each year, with 10-15% of fallers sustaining a serious injury. Reliable automated fall detection can increase confidence in people with fear of falling, promote active safe living for older adults, and reduce complications from falls. The performance of a 2-stage fall detection algorithm using impact magnitudes and changes in trunk angles derived from user-based motion sensors was evaluated under laboratory conditions. Ten healthy participants were instrumented on the front and side of the trunk with 3D accelerometers. Participants simulated 9 fall conditions and 6 common activities of daily living. Fall conditions were simulated on a protective mattress. The experimental data set comprised 750 events (45 fall events and 30 nonfall events per participant) that were classified by the fall detection algorithm as either a fall or a nonfall using inputs from 3D accelerometers. Significant differences for impacts recorded, trunk angle changes (p<0.01), and detection performances (p<0.05) were found between fall and nonfall conditions. The proposed algorithm detected fall events during simulated fall conditions with a success rate of 93% and a false-positive rate of 29% during nonfall conditions. Despite a slightly superior identification performance for the accelerometer located on the front of the trunk, no significant differences were found between the two motion sensor locations. Automated detection of fall events based on user-based motion sensing and fuzzy logic shows promising results. Additional rules and optimization of the algorithm will be needed to decrease the false-positive rate.