Search Results

The aim of the study was to determine the effects of 8 weeks of moderate exercise training, on 24-hour free living energy expenditure in previously sedentary post-menopausal women. The experimental group (EX) included 9 women. Ten non-exercising control subjects (CON) were recruited to undergo pre- and post-testing. Estimated total daily energy expenditure (TDEE), total 24-hour heart beats (HB), total energy intake (TEI), resting metabolic rate, maximal oxygen consumption (V̇O_2max), body composition, and submaximal heart rate were measured before and after the exercise intervention. Body composition did not change (body fat % in CON 34.0 ± 4.0% vs. 33.9 ± 3.6% and EX 34.1 ± 4.0% vs. 34.0 ± 3.4%). Mean submaximal heart rate during steady-state exercise in EX was lower after training compared to CON (p < .05); however, V̇O_2max did not significantly (CON 1.96 ± 0.23 vs. 1.99 ± 0.241 LO₂/min and EX 1.86 ± 0.39 vs. 1.94 ± 0.30 LO₂/min). Neither estimated TDEE (CON, 11.6 ± 2.0 vs. 11.4 ± 2.78 MJ; and EX 11.4 ± 3.3 vs. 11.5 ± 2.5 MJ, pre vs. post, respectively), RMR (CON 134.2 ± 9.4 vs. 136.9 ± 15.0 KJ/kgFFM/day, and EX 138.4 ± 6.4 vs. 140.7 ± 14.2 KJ/kgFFM/day, pre vs. post, respectively), TEI (CON 7.9 ± 2.2 vs. 8.2 ± 2.5 MJ, and EX 9.4 ±1.6 vs. 8.3 ± 2.8 MJ), nor HB (CON 110,808 ± 12,574 vs. 107,366 ± 12,864 beats, and EX 110,188 ± 9,219 vs. 114,590 ± 12,750 beats) change over 8 weeks in either group. These data suggest that a moderate exercise program may not impact on TDEE, RMR, TEI, or HB in previously sedentary, older women.

The aims of the study were to determine if medium-chain triacylglycerol (MCT), ingested in combination with carbohydrate (CHO), would alter substrate metabolism and improve simulated competitive ultra-endurance cycling performance. Eight endurance-trained cyclists took part in this randomized, single-blind crossover study. On two separate occasions, subjects cycled for 270 min at 50% of peak power output, interspersed with four 75 kJ sprints at 60 min intervals, followed immediately by a 200 kJ time-trial. One hour prior to the exercise trials, subjects ingested either 75 g of CHO or 32 g of MCT, and then ingested 200 mL of a 10% CHO (wt/vol) solution or a 4.3% MCT + 10% CHO (wt/vol) solution every 20 min during the CHO and MCT trials, respectively. During the constant-load phases of the 270 min exercise trial, VO_2, RER, and heart rate were measured at 30 min intervals and gastrointestinal (GI) symptoms were recorded. There was no difference in VO₂ or RER between the MCT and CHO trials (P = 0.40). Hourly sprint (P = 0.03 for trial x time interaction) and time-trial times (14:30 ± 0.58 vs. 12:36 ± 1:6, respectively, P < 0.001) were slower in the MCT than the CHO trial. Half the subjects experienced GI symptoms with MCT ingestion. In conclusion, MCTs ingested prior to exercise and co-ingested with CHO during exercise did not alter substrate metabolism and significantly compromised sprint performance during prolonged ultra-endurance cycling exercise.

The aim of this study was to assess the validity and reliability of the Yale Physical Activity Survey (YPAS) and the short version of the International Physical Activity Questionnaire (IPAQ) in older South African adults. The YPAS includes measures of weekly energy expenditure (EE) for housework, yard work, caregiving, exercise, and recreation. The IPAQ measures total time and EE during vigorous and moderate activity, walking, and sitting. The instruments were administered twice for test–retest reliability (men, n = 52, 68 ± 5.4 years, and women, n = 70, 66 ± 5.8 years). Data for criterion validity were obtained from accelerometers. YPAS reliability ranged from r = .44 to.80 for men and r = .59 to .99 for women (p < .0001). IPAQ reliability was lower for men (r = .29 to .76) than for women (r = .46 to .77). Criterion validity of the YPAS was .31 to .54 for men and .26 to .29 for women. The YPAS and short IPAQ had comparable results for reliability and criterion validity.

We studied 21 ballet dancers aged 19.4 ± 1.4 years, hypothesizing that undernu-trition was a major factor in menstrual irregularity in this population. Menstrual history was determined by questionnaire. Eight dancers had always been regular (R). Thirteen subjects had a history of menstrual irregularity (HI). Of these, 2 were currently regularly menstruating, 3 had short cycles, 6 were oligomenorrheic, and 2 were amenorrheic. Subjects completed a weighed dietary record and an Eating Attitudes Test (EAT). The following physiological parameters were measured: body composition by anthropometry, resting metabolic rate (RMR) by open-circuit indirect calorimetry, and serum thyroid hormone concentrations by radioimmunoassay. R subjects had significantly higher RMR than HI subjects. Also, HI subjects had lower RMR than predicted by fat-free mass, compared to the R subjects. Neitherreported energy intake nor serum thyroid hormone concentrations were different between R and HI subjects. EAT scores varied and were not different between groups. We concluded that in ballet dancers, low RMR is more strongly associated with menstrual irregularity than is currentreported energy intake or serum thyroid hormone concentrations.

Background: To investigate the mediation effects of physical activity (PA) on the relationship between the perceived neighborhood aesthetic environment and overweight/obesity in free-living South Africans. Methods: A cross-sectional study of 671 adults aged ≥ 35 years was analyzed. PA was assessed using the validated International Physical Activity Questionnaire. Perceived neighborhood aesthetics was assessed using the Neighborhood Environment Walkability Scale Questionnaire. Results: Of 671 participants, 76.0% were women, 34.1% aged 45–54 years, and 69.2% were overweight or obese. In adjusted logistic regression models, overweight/obesity was significantly associated with neighborhood aesthetics [odds ratio (OR) = 0.68; 95% confidence interval (CI), 0.50–0.93] and PA (OR = 0.65; 95% CI, 0.65–0.90). In expanded multivariable models, overweight/obesity was associated with age 45–55 years (OR = 1.59; 95% CI, 1.05–2.40), female gender (OR = 6.24; 95% CI, 3.95–9.86), tertiary education (OR = 4.05; 95% CI, 1.19–13.86), and urban residence (OR = 2.46; 95% CI, 1.66–3.65). Conclusion: Aesthetics was positively associated with PA; both aesthetics and PA were negatively associated with overweight and obesity. There was no evidence to support a significant mediating effect of PA on the relationship between aesthetics and overweight/obesity. Future studies should consider objective assessment of aesthetics and PA. In addition, future studies should consider using longitudinal design to evaluate food-related environments, which are related to overweight or obesity.

The impact of altered blood glucose concentrations on exercise metabolism and performance after a low carbohydrate (CHO) diet was investigated. In random order, 1 wk apart, 9 trained men underwent euglycemic (CI) or placebo (PI) clamps, while performing up to 150 min of cycling at 70% VO_2max, after 48 h on a low CHO diet. The range in improvement in endurance capacity with glucose infusion was large (28 ± 26%, P < 0.05). Fifty-six percent of subjects in CI failed to complete 150 min of exercise despite maintenance of euglycemia, while only 2 subjects in PI completed 150 min of exercise, despite being hypoglycemic. Total CHO oxidation remained similar between trials. Despite longer exercise times in CI, similar amounts of muscle glycogen were used to PI. Maintenance of euglycemia in the CHO-depleted state might have an ergogenic effect, however, the effect is highly variable between individuals and independent of changes in CHO oxidation.