Biomedical subjects

David J Stensel

Publications and source records attributed to David J Stensel.

6 recordsLinked to original sources

PubMed2007

Exercise and postprandial plasma triacylglycerol concentrations in healthy adolescent boys.

PURPOSE: Atherosclerosis is initiated in childhood. Therefore, reducing postprandial triacylglycerol concentrations ([TAG]), even in young people, could potentially slow atherogenic progression. This study investigated whether continuous-exercise and intermittent-games activity would reduce postprandial [TAG] in adolescent boys. METHODS: Nineteen subjects were randomly assigned to either a continuous-exercise group (N = 10) or an intermittent-games group (N = 9) and underwent two 2-d trials. Trials were performed a minimum of 7 d apart in a randomized order, consisting of a rest trial and either a continuous-exercise or intermittent-games trial. In the rest trial, subjects took no exercise on day 1. On day 1 of the exercise trial, subjects completed four blocks (approximately 15 min each) of uphill treadmill walking or intermittent-games activity with 3 min of rest between each block. On day 2, subjects came to the laboratory after an overnight fast, and finger-prick blood samples were obtained in the fasted state. Subjects then consumed a test meal (1.25 g of fat, 1.07 g of carbohydrate, 0.20 g of protein, and 67 kJ.kg(-1) body mass). Further blood samples were collected at 30 and 45 min and at 1, 3, 4, and 6 h postprandially. RESULTS: The total area under the plasma [TAG] versus time curve was lower on day 2 after exercise than the rest condition in both groups (Student's t-tests for correlated means: continuous-exercise group 14%, P = 0.050; intermittent-games group 26%, P = 0.002). CONCLUSION: Both continuous-exercise and intermittent-games activity reduce [TAG] in healthy adolescent boys when performed the afternoon before ingesting a high-fat meal.

Adolescent↗

PubMed2006

Exercise and postprandial lipemia: effect of continuous compared with intermittent activity patterns.

BACKGROUND: Guidelines state that accumulated physical activity is beneficial for health, but a minimum duration of 10 min per activity bout is recommended. Limited information regarding the effects of short (< 10 min) bouts of activity on health is available, and no studies of the effects of such short bouts of activity on postprandial lipemia have been conducted. OBJECTIVE: The objective was to compare the effects of accumulating ten 3-min bouts of exercise with those of one 30-min bout of exercise on postprandial plasma triacylglycerol concentrations. DESIGN: Ten men aged 21-32 y completed three 2-d trials > or = 1 wk apart in a randomized repeated-measures design. On day 1, the subjects rested (no exercise) or ran at 70% of maximum oxygen uptake in either ten 3-min bouts (30 min rest between each) or one continuous 30-min bout. On day 2, the subjects rested and consumed test meals (0.69 g fat, 0.95 g carbohydrate, 0.31 g protein, and 46 kJ/kg body mass) for breakfast and lunch. Venous blood samples were obtained in the fasted state and for 7 h postprandially on day 2. RESULTS: Postprandial plasma triacylglycerol concentrations were lower throughout day 2 of both the accumulation exercise trial and the continuous exercise trial than during the control trial (main effect of trial: P < 0.001, 2-factor analysis of variance). CONCLUSIONS: Accumulating multiple short bouts of exercise throughout the day effectively reduce postprandial plasma triacylglycerol concentrations to an extent similar to that of a single 30-min session of exercise in healthy young men.

Adult↗

PubMed2006

Increased postprandial triacylglycerol concentrations following resistance exercise.

PURPOSE: There is conflicting evidence whether a single bout of resistance exercise performed the day before a test meal can lower postprandial triacylglycerol (TAG) concentrations. The present study examined the effect of a single session of resistance exercise, performed the same day as a test meal, on postprandial TAG concentrations in resistance-trained males. METHODS: Ten healthy males aged 25 (SD 2.6) yr performed two trials at least 1 wk apart in a counterbalanced, randomized design. In each trial, participants consumed a test meal (0.89 g of fat, 1.23 g of carbohydrate, 0.4 g of protein, 60 kJ.kg body mass). Before one meal, participants performed a 90-min bout of resistance exercise. Before the other meal, participants were inactive (control trial). Resistance exercise was performed using free weights and included three sets of 12 repetitions of each of 10 exercises. Sets were performed at 80% of 12-repetition maximum with a 3-min work and rest interval. Venous blood samples were obtained in the fasted state and for 5 h postprandially. RESULTS: Total area under the plasma TAG concentration versus time curve was higher (Student's t-test P = 0.008) on the exercise than control trial (mean +/- SE: 11.76 +/- 1.64 vs 7.94 +/- 1.08 mmol x L(-1) x 5 h(-1), respectively). Total area under the plasma myoglobin concentration versus time curve was higher (Student's t-test P = 0.010) on the exercise than control trial (16.68 +/- 3.34 vs 6.80 +/- 0.64 nmol x L(-1) x 5 h(-1); respectively). CONCLUSION: A single bout of resistance exercise can cause a transient elevation in postprandial TAG concentrations. The elevations in plasma myoglobin suggest postexercise muscle damage. Further investigation is needed to see if these findings are linked.

Adult↗

PubMed2006

Effects of intermittent games activity on postprandial lipemia in young adults.

PURPOSE: To investigate whether a single session of intermittent games activity would reduce postprandial lipemia. METHODS: Twelve male volunteers completed three 2-d trials: rest, continuous exercise, and intermittent games activity. Trials were performed a minimum of 6 d apart in a balanced crossover design. In the rest trial, subjects took no exercise on day 1. On day 1 of the continuous and intermittent games trials, subjects completed four blocks (approximately 15 min per block) of uphill treadmill walking or intermittent games activity with 3 min of rest between each block. On day 2, subjects came to the laboratory for an oral fat tolerance test (blood taken fasted and for 6 h following a high-fat test meal (1.25 g of fat and 1.07 g of carbohydrate per kilogram of body mass)). RESULTS: The intermittent games protocol elicited a higher exercise intensity than the continuous trial (lactate: 4.3+/-0.6 vs 2.4+/-0.3 mmol.L; % VO2max: 72+/-2 vs 62+/-1, respectively; mean+/-SE). The total area under the plasma triacylglycerol (TAG) concentration versus time curve was lower in both the intermittent games (25%, P=0.001) and the continuous (19%, P=0.028) trials than in the rest trial. CONCLUSION: These findings show for the first time that intermittent games activity can reduce postprandial lipemia, and confirm that continuous exercise reduces postprandial lipemia in young adults.

Adult↗

PubMed2005

A single session of resistance exercise does not reduce postprandial lipaemia.

This study investigated the effect of a single session of resistance exercise on postprandial lipaemia. Eleven healthy normolipidaemic men with a mean age of 23 (standard error = 1.4) years performed two trials at least 1 week apart in a counterbalanced randomized design. In each trial, participants consumed a test meal (1.2 g fat, 1.1 g carbohydrate, 0.2 g protein and 68 kJ x kg(-1) body mass) between 08.00 and 09.00 h following a 12 h fast. The afternoon before one trial, the participants performed an 88 min bout of resistance exercise. Before the other trial, the participants were inactive (control trial). Resistance exercise was performed using free weights and included four sets of 10 repetitions of each of 11 exercises. Sets were performed at 80% of 10-repetition maximum with a 2 min work and rest interval. Venous blood samples were obtained in the fasted state and at intervals for 6 h postprandially. Fasting plasma triacylglycerol (TAG) concentration did not differ significantly between control (1.03 +/- 0.13 mmol x l(-1)) and exercise (0.94 +/- 0.09 mmol x l(-1)) trials (mean +/- standard error). Similarly, the 6 h total area under the plasma TAG concentration versus time curve did not differ significantly between the control (9.84 +/- 1.40 mmol l(-1) x 6 h(-1)) and exercise (9.38 +/- 1.12 mmol x l(-1) x 6 h(-1)) trials. These findings suggest that a single session of resistance exercise does not reduce postprandial lipaemia.

Adolescent↗

PubMed2004

Health-enhancing physical activity and sedentary behaviour in children and adolescents.

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.

Adolescent↗