An update on accumulating exercise and postprandial lipaemia: translating theory into practice

Over the last two decades, significant research attention has been given to the acute effect of a single bout of exercise on postprandial lipaemia. A large body of evidence supports the notion that an acute bout of aerobic exercise can reduce postprandial triacylglycerol (TAG) concentrations. However, this effect is short-lived emphasising the important role of regular physical activity for lowering TAG concentrations through an active lifestyle. In 1995, the concept of accumulating physical activity was introduced in expert recommendations with the advice that activity can be performed in several short bouts throughout the day with a minimum duration of 10 minutes per activity bout. Although the concept of accumulation has been widely publicised, there is still limited scientific evidence to support it but several studies have investigated the effects of accumulated activity on health-related outcomes to support the recommendations in physical activity guidelines. One area, which is the focus of this review, is the effect of accumulating exercise on postprandial lipaemia. We propose that accumulating exercise will provide additional physical activity options for lowering postprandial TAG concentrations relevant to individuals with limited time or exercise capacity to engage in more structured forms of exercise, or longer bouts of physical activity. The benefits of accumulated physical activity might translate to a reduced risk of cardiovascular disease in the long-term. Copyright © 2013 The Korean Society for Preventive Medicine

High intensity interval exercise and postprandial triacylglycerol

This review examined if high intensity interval exercise (HIIE) reduces postprandial triacylglycerol (TAG) concentrations. Fifteen studies were identified, in which the effect of interval exercise conducted at an intensity of >65% of maximal oxygen uptake was evaluated on postprandial TAG concentrations. Analysis was divided between studies which included supramaximal exercise and those which included submaximal interval exercise. Ten studies examined the effect of a single session of low-volume HIIE including supramaximal sprints on postprandial TAG. Seven of these studies noted reductions in postprandial total TAG area under the curve the morning after exercise of between ~10%-21% compared with rest but three investigations found no significant difference in TAG concentrations. Variations in the HIIE protocol used, inter-individual variation or insufficient time post-exercise for an increase in lipoprotein lipase activity are proposed reasons for the divergent results among studies. Five studies examined the effect of high-volume submaximal interval exercise on postprandial TAG. Four of these studies were characterised by high exercise energy expenditure and effectively attenuated total postprandial TAG concentrations by ~15%-30% but one study with a lower energy expenditure found no effect on TAG. The evidence suggests that supramaximal HIIE can induce large reductions in postprandial TAG concentrations but findings are inconsistent. Submaximal interval exercise offers no TAG metabolic or time advantage over continuous aerobic exercise but could be appealing in nature to some individuals. Future research should examine if submaximal interval exercise can reduce TAG concentrations in line with more realistic and achievable exercise durations of 30 minutes per day

Influence of prolonged treadmill running on appetite, energy intake and circulating concentrations of acylated ghrelin

The effects of prolonged treadmill running on appetite, energy intake and acylated ghrelin (an appetite stimulating hormone) were examined in 9 healthy males over the course of 24 h. Participants completed 2 experimental trials (exercise and control) in a randomised - crossover fashion. In the exercise trial participants ran for 90 min at 68.8 ± 0.8% of maximum oxygen uptake followed by 8.5 h of rest. Participants returned to the laboratory on the following morning to provide a fasting blood sample and ratings of appetite (24 h measurement). No exercise was performed on the control trial. Appetite was measured within the laboratory using visual analogue scales and energy intake was assessed from ad libitum buffet meals. Acylated ghrelin was determined from plasma using an ELISA assay. Exercise transiently suppressed appetite and acylated ghrelin but each remained no different from control values in the hours afterwards. Furthermore, despite participants expending 5324 kJ during exercise there was no compensatory increase in energy intake (24 h energy intake; control 17191 kJ, exercise 17606 kJ). These findings suggest that large energy deficits induced by exercise do not lead to acute compensatory responses in appetite, energy intake or acylated ghrelin

A single session of treadmill running has no effect on plasma total ghrelin concentrations

Ghrelin is a hormone stimulating hunger. Intense exercise has been shown to temporarily suppress hunger post-exercise. The present study investigated whether post-exercise hunger suppression is mediated by reduced plasma total ghrelin concentrations

Different patterns of walking and postprandial triglycerides in older women

Purpose: Although a single bout of continuous exercise (≥30 min) reduces postprandial triglyceride (TG), little evidence is available regarding the effect of multiple short (≤10 min) bouts of exercise on postprandial TG in individuals at increased risk of cardiovascular diseases. This study compared the effect of different patterns of walking on postprandial TG in postmenopausal, older women with hypertriglyceridemia. Methods: Twelve inactive women (aged 71 ± 5 yrs, mean ± S.D.) with hypertriglyceridemia (fasting TG ≥ 1.70 mmol/L) completed three, one-day laboratory-based trials in a random order: 1) control, 2) continuous walking, and 3) multiple short bouts of walking. On the control trial, participants sat in a chair for 8 hours. For the walking trials, participants walked briskly in either one 30-min bout in the morning (0900-0930) or twenty 90-sec bouts over 8 hours. Except for walking both exercise trials mimicked the control trial. In each trial, participants consumed a standardized breakfast (0800) and lunch (1100). Venous blood samples were collected in the fasted state and at 2, 4, 6 and 8 h after breakfast. Results: The serum TG incremental area under the curve was 35% and 33% lower on the continuous and multiple short bouts of walking trials than the control trial (8.2 ± 3.1 vs 8.5 ± 5.4 vs 12.7 ± 5.8 mmol∙8h/L respectively, main effect of trial: ES = 0.459, P = 0.001). Conclusions: Accumulating walking in short bouts limits postprandial TG in at-risk, inactive older women with fasting hypertriglyceridemia

Acute effect of exercise intensity and duration on acylated ghrelin and hunger in men

Acute exercise transiently suppresses the orexigenic gut hormone acylated ghrelin, but the extent exercise intensity and duration determine this response is not fully understood. The effects of manipulating exercise intensity and duration on acylated ghrelin concentrations and hunger were examined in two experiments. In experiment one, nine healthy males completed three, 4-hour conditions (control, moderate-intensity running (MOD) and vigorous-intensity running (VIG)), with an energy expenditure of ~2.5 MJ induced in both MOD (55 min running at 52% peak oxygen uptake (VO2peak)) and VIG (36 min running at 75% VO2peak). In experiment two, nine healthy males completed three, 9-hour conditions (control, 45 min running (EX45) and 90 min running (EX90)). Exercise was performed at 70% VO2peak. In both experiments, participants consumed standardised meals, and acylated ghrelin concentrations and hunger were quantified at predetermined intervals. In experiment one, delta acylated ghrelin concentrations were lower than control in MOD (ES=0.44, P=0.01) and VIG (ES=0.98, P<0.001); VIG was lower than MOD (ES=0.54, P=0.003). Hunger ratings were similar across the conditions (P=0.35). In experiment two, delta acylated ghrelin concentrations were lower than control in EX45 (ES=0.77, P<0.001) and EX90 (ES=0.68, P<0.001); EX45 and EX90 were similar (ES=0.09, P=0.55). Hunger ratings were lower than control in EX45 (ES=0.20, P=0.01) and EX90 (ES=0.27, P=0.001); EX45 and EX90 were similar (ES=0.07, P=0.34). Hunger and delta acylated ghrelin concentrations remained suppressed at 1.5h in EX90 but not EX45. In conclusion, exercise intensity, and to a lesser extent duration, are determinants of the acylated ghrelin response to acute exercise

Supplemental information files for The influence of physical activity on neural responses to visual food cues in humans: A systematic review of functional magnetic resonance imaging studies

© the authors, CC-BY 4.0Supplemental files for article The influence of physical activity on neural responses to visual food cues in humans: A systematic review of functional magnetic resonance imaging studiesThis systematic review examined whether neural responses to visual food-cues measured by functional magnetic resonance imaging (fMRI) are influenced by physical activity. Seven databases were searched up to February 2023 for human studies evaluating visual food-cue reactivity using fMRI alongside an assessment of habitual physical activity or structured exercise exposure. Eight studies (1 exercise training, 4 acute crossover, 3 cross-sectional) were included in a qualitative synthesis. Structured acute and chronic exercise appear to lower food-cue reactivity in several brain regions, including the insula, hippocampus, orbitofrontal cortex (OFC), postcentral gyrus and putamen, particularly when viewing high-energy-density food cues. Exercise, at least acutely, may enhance appeal of low-energy-density food-cues. Cross-sectional studies show higher self-reported physical activity is associated with lower reactivity to food-cues particularly of high-energy-density in the insula, OFC, postcentral gyrus and precuneus. This review shows that physical activity may influence brain food-cue reactivity in motivational, emotional, and reward-related processing regions, possibly indicative of a hedonic appetite-suppressing effect. Conclusions should be drawn cautiously given considerable methodological variability exists across limited evidence.</p

Exercise and postprandial lipemia: effect of continuous versus intermittent activity patterns

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

Postprandial metabolism and physical activity in Asians: a narrative review

The widespread benefits of physical activity in enhancing health and lowering the risk of non-communicable chronic diseases are well established across populations globally. Nevertheless, the prevalence of several lifestyle-related chronic diseases, including cardiovascular, varies markedly across countries and ethnicities. Direct ethnic comparative studies on the health benefits of physical activity are sparse and evidence-based physical activity guidelines are not ethnicity specific. Indeed, physical activity guidelines in some Asian countries were developed primarily based on data from Western populations even though the magnitude of potential benefit may not be the same among different ethnic groups. Unfavourable diurnal perturbations in postprandial triglyceride and glucose are risk factors for cardiovascular disease. This narrative review summarises differences in these risk factors primarily between individuals of Asian and white European descent but also within different Asian groups. Moreover, the variable effects of physical activity on mitigating risk factors among these ethnic groups are highlighted along with the underlying metabolic and hormonal factors that potentially account for these differences. Future ethnic comparative studies should include investigations in understudied ethnic groups, such as those of East Asian origin, given that the effectiveness of physical activity for ameliorating cardiovascular disease varies even among Asian groups

Increased postprandial triacylglycerol concentrations following resistance exercise

Purpose: There is conflicting evidence as to 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) years performed two trials at least one-week apart in a counterbalanced randomized design. In each trial, participants consumed a test meal (0.89 g fat, 1.23 g carbohydrate, 0.4 g protein, 60 kJ, per kg body mass). Prior to one meal participants performed a 90-minute bout of resistance exercise. Prior to the other meal participants were inactive (control trial). Resistance exercise was performed using free weights and included 3 sets of 12 repetitions of each of 10 exercises. Sets were performed at 80% of 12-repetition maximum with a 3 minute work and rest interval. Venous blood samples were obtained in the fasted state and for 5 hours 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 versus 7.94 1.08 mmol•L-1•5 h; 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 versus 6.80 0.64 nmol•L-1•5 h; respectively). Conclusion: A single bout of resistance exercise may cause a transient elevation in postprandial TAG concentrations. The elevations in plasma myoglobin suggest post-exercise muscle damage. Further investigation is needed to see if these findings are linked