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Combined effects of continuous exercise and intermittent active interruptions to prolonged sitting on postprandial glucose, insulin, and triglycerides in adults with obesity: a randomized crossover trial.
Wheeler, MJ, Green, DJ, Cerin, E, Ellis, KA, Heinonen, I, Lewis, J, Naylor, LH, Cohen, N, Larsen, R, Dempsey, PC, et al
The international journal of behavioral nutrition and physical activity. 2020;(1):152
Abstract
BACKGROUND Postprandial glucose, insulin, and triglyceride metabolism is impaired by prolonged sitting, but enhanced by exercise. The aim of this study was to assess the effects of a continuous exercise bout with and without intermittent active interruptions to prolonged sitting on postprandial glucose, insulin, and triglycerides. METHODS Sedentary adults who were overweight to obese (n = 67; mean age 67 yr SD ± 7; BMI 31.2 kg∙m- 2 SD ± 4.1), completed three conditions: SIT: uninterrupted sitting (8-h, control); EX+SIT: sitting (1-h), moderate-intensity walking (30-min), uninterrupted sitting (6.5-h); EX+BR: sitting (1-h), moderate-intensity walking (30- min), sitting interrupted every 30-min with 3-min of light-intensity walking (6.5 h). Participants consumed standardized breakfast and lunch meals and blood was sampled at 13 time-points. RESULTS When compared to SIT, EX+SIT increased total area under the curve (tAUC) for glucose by 2% [0.1-4.1%] and EX+BR by 3% [0.6-4.7%] (all p < 0.05). Compared to SIT, EX+SIT reduced insulin and insulin:glucose ratio tAUC by 18% [11-22%] and 21% [8-33%], respectively; and EX+BR reduced values by 25% [19-31%] and 28% [15-38%], respectively (all p < 0.001 vs SIT, all p < 0.05 EX+SIT-vs-EX+BR). Compared to SIT, EX+BR reduced triglyceride tAUC by 6% [1-10%] (p = 0.01 vs SIT), and compared to EX+SIT, EX+BR reduced this value by 5% [0.1-8.8%] (p = 0.047 vs EX+SIT). The magnitude of reduction in insulin tAUC from SIT-to-EX+BR was greater in those with increased basal insulin resistance. No reduction in triglyceride tAUC from SIT-to-EX+BR was apparent in those with high fasting triglycerides. CONCLUSIONS Additional reductions in postprandial insulin-glucose dynamics and triglycerides may be achieved by combining exercise with breaks in sitting. Relative to uninterrupted sitting, this strategy may reduce postprandial insulin more in those with high basal insulin resistance, but those with high fasting triglycerides may be resistant to such intervention-induced reductions in triglycerides. TRIAL REGISTRATION Australia New Zealand Clinical Trials Registry ( ACTRN12614000737639 ).
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Effects of Ramadan intermittent fasting on lipid and lipoprotein parameters: An updated meta-analysis.
Mirmiran, P, Bahadoran, Z, Gaeini, Z, Moslehi, N, Azizi, F
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2019;(9):906-915
Abstract
AIMS: This systematic review and meta-analysis aimed to clarify several aspects of intermittent fasting during the month of Ramadan on lipid and lipoprotein levels in apparently healthy subjects. DATA SYNTHESIS We searched PubMed, Scopus, and Embase databases and the reference lists of previous reviews, up to Feb 2019 for studies that investigated the effects of Ramadan fasting on fasting levels of triglycerides (TG), total cholesterol (TC), HDL-C, LDL-C, and VLDL-C among healthy subjects including pregnant women and athletic subjects. Studies were selected for quality assessment, meta-analyses, subgroup analyses, and meta-regressions; data of 33 eligible studies, conducted between 1978 and 2019, were included in the analysis. RESULTS Intermittent fasting showed no significant effect on circulating TG (WMD = -0.38 mg/dl, 95% CI = -5.33, 4.57), TC (WMD = -1.58 mg/dl, 95% CI = -6.04, 2.88), and LDL-C levels (WMD = 1.85 mg/dl, 95% CI = 0.77, 2.92). Overall, HDL-C (WMD = -2.97 mg/dl; 95% CI = -6.43, 0.48 mg/dl) and VLDL-C (WMD = -1.41 mg/dl; 95% CI = -2.73, -0.10 mg/dl) significantly decreased after Ramadan fasting. A significant increase in LDL-C levels was observed in athletic subjects (WMD = 2.97 mg/dl; 95% CI = 0.80, 5.13) and apparently healthy subjects (WMD = 1.81 mg/dl; 95% CI = 0.55, 3.07). Change in TG levels was associated with age (β = -0.94, P = 0.043), its baseline values (β = -0.44, P = 0.001), and weight change during the fasting period (β = -0.57, P = 0.032). CONCLUSION Ramadan fasting may be accompanied by a moderate improvement of lipid and lipoprotein parameters, especially HDL-C levels; fasting appears to be more beneficial for men and athletic subjects.
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Exercise energy expenditure and postprandial lipemia in girls.
Tolfrey, K, Engstrom, A, Murphy, C, Thackray, A, Weaver, R, Barrett, LA
Medicine and science in sports and exercise. 2014;(2):239-46
Abstract
PURPOSE This study aimed to examine the effect of 30 and 60 min of moderate-intensity treadmill walking on postprandial triacylglycerol concentrations ([TAG]) in healthy girls. METHODS Eighteen 10- to 14-yr-old girls (mean ± SD; body mass = 48 ± 11 kg, body fat = 19.0 ± 4.6%, peak oxygen uptake [V˙O2] = 47 ± 6 mL·kg·min) completed three 2-d trials in a counterbalanced crossover design, each separated by 14 d. On day 1, they rested (CON) or completed 30 min (EX30) or 60 min (EX60) of intermittent treadmill exercise at 56% peak V˙O2, inducing energy expenditures of 777 and 1536 kJ (186 and 367 kcal), respectively. On day 2, after a 12-h fast, a capillary blood sample was taken for fasting [TAG] before a high-fat milkshake (80 kJ·kg(-1) body mass) was consumed. Further blood samples were taken hourly over a 6-h postprandial rest period for [TAG]. ANOVA and Student's t-tests were used to analyze the data. RESULTS Fasting [TAG] was lower in EX60 than CON (95% confidence interval [CI] = -0.36 to 0.04, effect size (ES) = 0.41) and EX30 (95% CI = -0.47 to 0.04, ES = 0.46); all group mean concentrations were low (≤ 0.90 mmol·L(-1)). The main effect for condition revealed differences in postprandial [TAG] over time (ES = 0.36). The EX60 total area under the [TAG] versus time curve was lower than CON (95% CI = -2.66 to -0.04, ES 0.40) and EX30 (95% CI = -2.11 to 0.15, ES = 0.30); CON and EX30 were similar (95% CI = -1.44 to 0.71, ES = 0.10). CONCLUSION This study demonstrates that 60 min but not 30 min of moderate treadmill exercise, with a gross energy expenditure of 1536 kJ (367 kcal), attenuated postprandial [TAG] in girls.
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Exercise and postprandial lipemia: effect of continuous compared with intermittent activity patterns.
Miyashita, M, Burns, SF, Stensel, DJ
The American journal of clinical nutrition. 2006;(1):24-9
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Abstract
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.