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

Increasing meal frequency in combination with exercise mitigates postprandial triacylglycerol

Background: This study examined how manipulating meal frequency, with and without exercise, affects postprandial triacylglycerol (TAG). Methods: Fourteen sedentary men completed four 2-day trials in a non-counterbalanced random crossover order: (i) consumption of one large high fat milkshake without exercise (1-CON); (ii) consumption of two smaller high fat milkshakes without exercise (2-CON); (iii) consumption of one large high fat milkshake with exercise (1-EX); and (iv) consumption of two small high fat milkshakes with exercise (2-EX) – total energy intake was standardized across trials. On Day 1, participants rested (1-CON and 2- CON) or walked briskly for 60 minutes (1-EX and 2-EX). On Day 2, participants consumed either a single large high-fat milkshake (75% fat) (1-CON and 1-EX) for breakfast or two smaller iso-energetic milkshakes (2-CON and 2-EX) for breakfast and lunch. Plasma TAG were measured fasting and for 7 hours after breakfast. Results: Peak incremental TAG was 30% lower on 2-EX than 1-CON (P = .041; d = 0.38). Postprandial TAG increased more rapidly in the first 4 hours in 1-CON than other trials, but at 6 hours TAG was exaggerated in 2-CON compared with 1-CON. Conclusions: Increasing meal frequency after exercise, without altering overall fat intake, attenuates postprandial TAG

Increased complexities in visual search behavior in skilled players for a self-paced aiming task

The badminton serve is an important shot for winning a rally in a match. It combines good technique with the ability to accurately integrate visual information from the shuttle, racket, opponent, and intended landing point. Despite its importance and repercussive nature, to date no study has looked at the visual search behaviors during badminton service in the singles discipline. Unlike anticipatory tasks (e.g., shot returns), the serve presents an opportunity to explore the role of visual search behaviors in movement control for self-paced tasks. Accordingly, this study examined skill-related differences in visual behavior during the badminton singles serve. Skilled (n D 12) and less skilled (n D 12) participants performed 30 serves to a live opponent, while real-time eye movements were captured using a mobile gaze registration system. Frame-by-frame analyses of 662 serves were made and the skilled players took a longer preparatory time before serving. Visual behavior of the skilled players was characterized by significantly greater number of fixations on more areas of interest per trial than the less skilled. In addition, the skilled players spent a significantly longer time fixating on the court and net, whereas the less skilled players found the shuttle to be more informative. Quiet eye (QE) duration (indicative of superior sports performance) however, did not differ significantly between groups which has implications on the perceived importance of QE in the badminton serve. Moreover, while visual behavior differed by skill level, considerable individual differences were also observed especially within the skilled players. This augments the need for not just group-level analyses, but individualized analysis for a more accurate representation of visual behavior. Findings from this study thus provide an insight to the possible visual search strategies as players serve in net-barrier games. Moreover, this study highlighted an important aspect of badminton relating to deception and the implications of interpreting visual behavior of players

Effects of caffeine supplementation on performance in ball games

Although a large body of evidence exists documenting the ergogenic properties of caffeine, most studies have focused on endurance performance. However, findings from endurance sports cannot be generalized to performance in ball games where, apart from having a high level of endurance, successful athletic performances require a combination of physiological, technical and cognitive capabilities. The purpose of this review was to critically evaluate studies that have examined the effect of a single dose of caffeine in isolation on one or more of the following performance measures: total distance, sprint performance, agility, vertical jump performance and accuracy in ball games. Searches of three major databases resulted in 19 studies (invasion games: 13; net-barrier games: 6) that evaluated the acute effects of caffeine on human participants, provided the caffeine dose administered, and included a ball games specific task or simulated match. Improvements in sprint performance were observed in 8 of 10 studies (80%), and vertical jump in 7 of 8 studies (88%). Equivocal results were reported for distance covered, agility and accuracy. Minor side effects were reported in 4 of 19 studies reviewed. Pre-exercise caffeine ingestion between 3.0 and 6.0 mg/kg of body mass appears to be a safe ergogenic aid for athletes in ball games. However, the efficacy of caffeine varies depending on various factors, including, but not limited to, the nature of the game, physical status and caffeine habituation. More research is warranted to clarify the effects of caffeine on performance measures unique to ball games, such as agility and accuracy. It is essential that athletes, coaches and practitioners evaluate the risk-benefit ratio of caffeine ingestion strategies on an individual case-by-case basis

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 aged 23 (SE 1.4) years performed two trials at least one-week apart in a counterbalanced randomized design. In each trial participants consumed a test meal (1.2g fat, 1.1g carbohydrate, 0.2 g protein and 68 kJ per kg body mass) between 08.00 and 09.00 following a 12 hour fast. The afternoon before one trial participants performed an 88 minute bout of resistance exercise. Prior to the other trial participants were inactive (control trial). Resistance exercise was performed using free weights and included 4 sets of 10-repetitions of each of 11 exercises. Sets were performed at 80% of 10 repetition maximum with a 2 minute 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 and exercise trials (mean SE: 1.03 0.13 mmol•L-1 versus 0.94 0.09 mmol•L-1; respectively). Similarly the 6 h total area under the plasma TAG concentration versus time curve did not differ significantly between control and exercise trials (9.84 1.40 mmol•L-1•6 h versus 9.38 1.12 mmol•L-1•6 h; respectively). These findings suggest that a single session of resistance exercise does not reduce postprandial lipaemia

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

Individual variation in hunger, energy intake and ghrelin responses to acute exercise

Purpose: To characterise the immediate and extended impact of acute exercise on hunger, energy intake and circulating acylated ghrelin concentrations using a large dataset of homogenous experimental trials; and to describe the variation in responses between individuals. Methods: Data from 17 of our group’s experimental crossover trials were aggregated yielding a total sample of 192 young, healthy, males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69 ± 5% VO2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours post-exercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analogue scales completed at 30 min intervals whilst ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise. Results: At group-level, exercise transiently suppressed hunger (P < 0.010; Cohen’s d = 0.77) but did not affect energy intake. Acylated ghrelin was suppressed during exercise (P < 0.001; Cohen’s d = 0.10) and remained significantly lower than control (no exercise) afterwards (P < 0.024; Cohen’s d = 0.61). Between participants, there were notable differences in responses however a large proportion of this spread lay within the boundaries of normal variation associated with biological and technical assessment error. Conclusion: In young men, acute exercise suppresses hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true inter-individual variation from random differences within normal limits

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