D. J. Jacobsen

Physical Activity Across the Curriculum (PAAC): a randomized controlled trial to promote physical activity and diminish overweight and obesity in elementary school children

BACKGROUND Physical Activity Across the Curriculum (PAAC) was a three-year cluster randomized controlled trial to promote physical activity and diminish increases in overweight and obesity in elementary school children. METHODS Twenty-four elementary schools were cluster randomized to the Physical Activity Across the Curriculum intervention or served as control. All children in grades two and three were followed to grades four and five. Physical Activity Across the Curriculum promoted 90 min/wk of moderate to vigorous intensity physically active academic lessons delivered by classroom teachers. Body Mass Index was the primary outcome, daily Physical activity and academic achievement were secondary outcomes. RESULTS The three-year change in Body Mass Index for Physical Activity Across the Curriculum was 2.0+/-1.9 and control 1.9+/-1.9, respectively (NS). However, change in Body Mass Index from baseline to 3 years was significantly influenced by exposure to Physical Activity Across the Curriculum. Schools with > or =75 min of Physical Activity Across the Curriculum/wk showed significantly less increase in Body Mass Index at 3 years compared to schools that had <75 min of Physical Activity Across the Curriculum (1.8+/-1.8 vs. 2.4+/-2.0, p=0.02). Physical Activity Across the Curriculum schools had significantly greater changes in daily Physical activity and academic achievement scores. CONCLUSIONS The Physical Activity Across the Curriculum approach may promote daily Physical activity and academic achievement in elementary school children. Additionally, 75 min of Physical Activity Across the Curriculum activities may attenuate increases in Body Mass Index.

Beverage Consumption Patterns in Elementary School Aged Children across a Two-Year Period

Objective: Existing data was reexamined to determine changes in beverage consumption and associations between beverages consumed and BMI Z-score in children (n = 164) across two years. Methods: Beverages (milk, 100% juice, diet soda or sugar sweetened) and total caloric intake were calculated from a 24-hour diet recall. Height and weight were measured to calculate BMI. Subjects were categorized by BMI Z-score as normal weight, overweight, gained weight and lost weight. Data was collected at baseline and year 2. Results: Significant decreases in milk and increases in diet soda were found over two years in all subjects and normal weight, whereas overweight had a significant increase in diet soda consumption and a decrease in milk consumption that did not reach significance. Change in milk consumption was inversely correlated with sugar-sweetened beverage consumption. Increases in diet soda consumption were significantly greater for overweight and subjects who gained weight as compared to normal weight subjects. Baseline BMI Z-score and year 2 diet soda consumption predicted 83.1% of the variance in year 2 BMI Z-score. Conclusion: Shifts in beverage consumption were found in this convenient sample across two years. Diet soda consumption was the only type of beverage associated with year 2 BMI Z-score, and consumption was greater in overweight subjects and subjects who gained weight as compared to normal weight subjects at two years. Additional longitudinal data examining associations between beverage consumption and BMI is needed in children and adolescents, as consumption of regular and diet soda has become more of a social norm.

The effects of 18 months of intermittent vs continuous exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females.

OBJECTIVES: To compare the effects of 18 months of continuous vs intermittent exercise on aerobic capacity, body weight and composition, and metabolic fitness in previously sedentary, moderately obese females.DESIGN: Randomized, prospective, long-term cohort study. Subjects performed continuous exercise at 60–75% of maximum aerobic capacity, 3 days per week, 30 min per session, or exercised intermittently using brisk walking for two, 15 min sessions, 5 days per week.MEASURES: Aerobic capacity, body weight, body composition, and metabolic fitness (blood pressure, lipids, glucose and insulin).RESULTS: Significant improvements for aerobic capacity of 8% and 6% were shown for the continuous and intermittent exercise groups, respectively. Weight loss for the continuous exercise group was significant at 2.1% from baseline weight and the intermittent group was essentially unchanged. The continuous group showed a significant decrease in percentage of body fat and fat weight while the intermittent group did not. HDL cholesterol and insulin were significantly improved for both groups.CONCLUSIONS: In previously sedentary, moderately obese females, continuous or intermittent exercise performed long-term may be effective for preventing weight gain and for improving some measures of metabolic fitness.

Muscle damage and resting metabolic rate after acute resistance exercise with an eccentric overload.

PURPOSE The purpose of this investigation was to determine whether muscle damage caused from acute resistance exercise with an eccentric overload would influence resting metabolic rate (RMR) up to 72 h postexercise in resistance-trained (RT) and untrained (UT) subjects. METHODS Nine RT and 9 UT male subjects (mean +/- SD; age = 20.7 +/- 2.1 yr; body mass = 79.0 +/- 1.4 kg; height = 178.4 +/- 3.1 cm; and body fat = 10.2 +/- 1.6%) were measured for RMR, creatine kinase concentration ([CK]), and rating of perceived muscle soreness (RPMS) on five consecutive mornings. To induce muscle damage, after the measurements on day 2, each subject performed leg presses that emphasized the eccentric movement for 8 sets at his six-repetition maximum (6-RM). RESULTS Compared with baseline, the RMR (kJ x d(-1) and kJ x kg FFM(-1) x h(-1) was significantly elevated for RT and UT at 24 h and 48 h postexercise. From 24 h to 48 h to 72 h postexercise, RMR significantly decreased within both groups. The UT group had a significantly higher RMR at 24 h (9,705.4 +/- 204.5 kJ x d(-1)) and 48 h postexercise (8,930.9 +/- 104.4 kJ x d(-1)) when compared with the RT group (9,209.3 +/- 535.3 and 8,601.7 + 353.7 kJ x d(-1)). Both [CK] and RPMS showed a similar time course. CONCLUSION There was a significantly higher [CK] for the UT group at 24 h postexercise (320.4 +/- 20.1 U x L(-1)) and for both [CK] and RPMS at 48 h (1,140.3 +/- 37.1 U x L(-1) and 4.4 +/- 0.5, respectively) and 72 h postexercise (675.9 +/- 41.7 U x L(-1) and 1.67 +/- 0.5, respectively) when compared with the RT group (24 h, 201.9 +/- 13.4 U x L(-1); 48 h, 845.4 +/- 30.7 U x L(-1) and 3.7 +/- 0.5: and 72 h postexercise, 420.2 +/- 70.2 U x L(-1) and 0.89 +/- 0.3). These data indicate that eccentrically induced muscle damage causes perturbations in RMR up to 48 h postexercise.

The validity of the Stanford Seven-Day Physical Activity Recall in young adults.

PURPOSE To evaluate the criterion validity of the 7-Day Physical Activity Recall (7D-PAR) and factors associated with reporting error, in a sample of moderately overweight, young adult men and women. METHODS Average total daily energy expenditure (TDEE) and physical activity energy expenditure (PAEE) from the 7D-PAR were compared with the same parameters assessed by doubly labeled water in 17 men, age = 23.9 +/- 3.8 yr, and 29 women, age = 23.3 +/- 4.6 yr, who volunteered to participate in a 16-month supervised aerobic exercise trial. PAEE was estimated from the 7D-PAR and from DLW [0.9 * TDEE -resting metabolic rate (RMR) (indirect calorimetry)]. In addition, peak oxygen uptake and percent body fat were obtained. RESULTS No significant differences in TDEE (kJ.d-1) were noted between the 7D-PAR (11825 +/- 1779) and DLW (11922 +/- 2516) for the complete sample (N = 46) or for men (7D-PAR = 13198 +/- 1638, DLW = 13885 +/- 2754) or women (7D-PAR = 11018 +/- 1323, DLW = 10771 +/- 1457. The mean PAEE from the 7D-PAR was not different from DLW in the total sample (7D-PAR = 3286 +/- 502, DLW = 3508 +/- 1863) as well as in men (7D-PAR = 3650 +/- 490, DLW = 3989 +/- 2461) and women (3073 +/- 377, DLW = 3223 +/- 1360). In a regression model, PAEE, peak oxygen uptake, gender and percent fat accounted for 86% of the reporting error in total daily energy expenditure when using the 7D-PAR. CONCLUSION The 7D-PAR provided a reasonable estimate of both the mean TDEE and PAEE in this sample; however, estimates of energy expenditure on an individual basis using the PAR were subject to considerable error.

Comparison of a phone vs clinic approach to achieve 10% weight loss

Objective:To compare the efficacy of a phone vs a traditional face-to-face clinic approach to achieve 10% weight loss and weight maintenance.Design:Twenty-six week, randomized, controlled trial.Subjects:Twenty-four men and 72 women, ages 25–68 years, with a body mass index (BMI) of 33.2±3.8.Measurements:Weight loss at 12 weeks and weight maintenance at 26 weeks were the primary outcomes. Attendance, meal replacements (MRs), fruits/vegetables (F/V), and physical activity (PA) were measured weekly for process evaluation.Results:Median weight loss (range) from baseline at 12 weeks was significantly different for phone at 10.6 kg (16.6) or 10.4% and clinic at 12.7 kg (19.9) or 13.7%, and both were significantly different when compared with the control group with a weight loss of 0.25 kg (5.6) or 0.24%. Median weight loss at 26 weeks was 12.8 kg (23.4) or 13.0% from baseline for the phone group and 12.5 kg (35.2) or 12.6% from baseline for the clinic group (P>0.05).Conclusion:The median weight loss for both phone and clinic groups at 12 and 26 weeks exceeded the NHLBI guideline of 10% weight loss from baseline. The phone approach may be a viable option to the traditional weight management clinic for both service providers and participants.

Minimal resistance training improves daily energy expenditure and fat oxidation.

UNLABELLED Long-term resistance training (RT) may result in a chronic increase in 24-h energy expenditure (EE) and fat oxidation to a level sufficient to assist in maintaining energy balance and preventing weight gain. However, the impact of a minimal RT program on these parameters in an overweight college-aged population, a group at high risk for developing obesity, is unknown. PURPOSE We aimed to evaluate the effect of 6 months of supervised minimal RT in previously sedentary, overweight (mean +/- SEM, BMI = 27.7 +/- 0.5 kg x m(-2)) young adults (21.0 +/- 0.5 yr) on 24-h EE, resting metabolic rate (RMR), sleep metabolic rate (SMR), and substrate oxidation using whole-room indirect calorimetry 72 h after the last RT session. METHODS Participants were randomized to RT (one set, 3 d x wk(-1), three to six repetition maximums, nine exercises; N = 22) or control (C, N = 17) groups and completed all assessments at baseline and at 6 months. RESULTS There was a significant (P < 0.05) increase in 24-h EE in the RT (527 +/- 220 kJ x d(-1)) and C (270 +/- 168 kJ x d(-1)) groups; however, the difference between groups was not significant (P = 0.30). Twenty-four hours of fat oxidation (g x d(-1)) was not altered after RT; however, reductions in RT assessed during both rest (P < 0.05) and sleep (P < 0.05) suggested increased fat oxidation in RT compared with C during these periods. SMR (8.4 +/- 8.6%) and RMR (7.4 +/- 8.7%) increased significantly in RT (P < 0.001) but not in C, resulting in significant (P < 0.001) between-group differences for SMR with a trend for significant (P = 0.07) between-group differences for RMR. CONCLUSION A minimal RT program that required little time to complete (11min per session) resulted in a chronic increase in energy expenditure. This adaptation in energy expenditure may have a favorable impact on energy balance and fat oxidation sufficient to assist with the prevention of obesity in sedentary, overweight young adults, a group at high risk for developing obesity.

A comparison of methods for analyzing glucose and insulin areas under the curve following nine months of exercise in overweight adults.

OBJECTIVE: We examined three methods for calculating the area under the curve (AUC) following an oral glucose tolerance test (OGTT) in overweight adults prior to and after 9 months of exercise.METHOD: Subjects (n=27) were randomly assigned to a control (CON, n=9) or intervention (INT, n=18) group. INT performed supervised exercise 5 days per week, 45 min per session, at 65% of heart rate reserve. OGTTs were administered pre- and post-training. Blood was collected during a 75 g OGTT and analyzed for glucose (GLU) and insulin (INS) concentrations. AUCs were calculated using the incremental, positive incremental, and total AUC methods and the difference scores for pre- and post-training were determined.RESULTS: No differences were observed among the methods for glucose AUC for either group. Significant differences were observed for INT insulin AUC with total AUC (1525±3291 µU/1/180 min) significantly greater than incremental AUC (1112±3229 µU/1/180 min) or positive incremental AUC (1085±3195 µU/I/180 min). Total insulin AUC was significantly reduced following training for INT, while incremental and positive incremental insulin AUCs showed no change.CONCLUSION: These data suggest that the method of used to calculate AUC may affect the interpretation of whether or not an intervention was effective.

Glucose and insulin responses following 16 months of exercise training in overweight adults: the midwest exercise trial

The current study examined the insulin and glucose response during an oral glucose tolerance test (OGTT) in overweight young adults prior to and following exercise training in the Midwest Exercise Trial (MET). Subjects (N = 66) were randomly assigned to non-exercise control (CON; 16 females, 13 males) or exercise (EX; 22 females, 15 males) groups. EX performed supervised and verified exercise on 3 to 5 days per week in 20- to 45-minute sessions at 60% to 75% of heart rate reserve. OGTTs and assessments for body mass, body composition, and maximal oxygen consumption (Vo(2) max) were performed at baseline, and after 9 and 16 months of training. Blood was collected during a 75-g OGTT and analyzed for glucose and insulin concentrations with the total area under the glucose and insulin curves used in the analysis. The EX males had significant decreases from baseline to 9 months in body mass (94.8 +/- 12.5 to 89.2 +/- 9.8 kg) and percent fat (28.3 +/- 4.8 to 24.2 +/- 3.9) with no further changes at 16 months. CON females had significant increases in body mass (78.2 +/- 6.4 to 81.1 +/- 8.1 kg) and percent fat (36.6 +/- 4.2 to 37.8 +/- 4.7) from baseline to 16 months. Vo(2) max increased significantly from baseline to 9 months in the EX males (3.67 +/- 0.62 to 4.36 +/- 0.55 L/min) and EX females (2.53 +/- 0.32 to 2.99 +/- 0.42 L/min). For glucose area under the curve, there were no significant differences between EX or CON across the 16 months of the study. For insulin area under the curve, there was a significant decrease for male EX from baseline to 9 months (12,535 +/- 6,114 to 8,390 +/- 4,231 microU/L/180 min). We conclude that regular exercise in healthy, previously sedentary overweight adult males leads to improvements in Vo(2) max and weight loss and a reduction in the insulin concentration required to dispose of a set glucose load. In females, improvement in Vo(2) max without weight loss does not lead to improvement in insulin sensitivity.

A Comparison of Meal Replacements and Medication in Weight Maintenance after Weight Loss

Objective: To compare the use of meal replacements or medication during weight maintenance subsequent to weight loss using a very low-energy diet (VLED) in overweight or obese adults. Design: Participants followed a liquid VLED of 2177 kJ for 12 weeks followed by 4 weeks of re-orientation to solid foods. Participants were randomized at week 16 to receive either meal replacements or Orlistat both combined with a structured meal plan containing an energy value calculated to maintain weight loss. Subjects: Sixty-four women (age = 49.9 ± 10 y, weight = 101.6 ± 17.1 kg, height = 164.9 ± 6.0 cm, BMI = 36.7 ± 5.4 kg/m2) and 28 men (age = 53.7 ± 9.6 y, weight = 121.8 ± 16.0 kg, height = 178.7 ± 5.6 cm, BMI = 37.8 ± 4.9 kg/m2) completed a 1 year weight management program. Behavioral weight management clinics included topics on lifestyle, physical activity (PA), and nutrition. Participants met for 90 min weekly for 26 weeks, and then biweekly for the remaining 26 weeks. Outcomes: Minutes of PA, fruits and vegetables (FV), and pedometer steps were recorded on a daily basis and reported at each group meeting. Body weight was obtained at each group meeting. Results: During VLED, the MR group decreased body weight by 22.8 ± 6.1 kg and the Orlistat group decreased body weight by 22.3 ± 6.1 kg. During weight maintenance, there was no significant group by time interaction for body weight, PA, FV consumption, or pedometer steps. At week 16, the meal replacement group had a body weight of 85.4 ± 14.3 kg that increased to 88.1 ± 16.5 kg at 52 weeks (p < 0.05). At week 16, the Orlistat group had a body weight of 85.7 ± 17.9 kg that increased to 88.5 ± 20.3 kg at 52 weeks (p < 0.05). Conclusions: Subsequent to weight loss from a VLED, meal replacements and Orlistat treatments were both effective in maintaining weight significantly below baseline levels over a 52 week period of time. Meal replacements may be a viable alternative strategy to medications for weight maintenance.