Elsevier

Journal of Clinical Lipidology

Volume 11, Issue 5, September–October 2017, Pages 1268-1279.e1
Journal of Clinical Lipidology

Original Article
Regular activity breaks combined with physical activity improve postprandial plasma triglyceride, nonesterified fatty acid, and insulin responses in healthy, normal weight adults: A randomized crossover trial

https://doi.org/10.1016/j.jacl.2017.06.007Get rights and content

Highlights

  • Regularly activity breaks reduce postprandial triglycerides in healthy adults.

  • This attenuation is measured ∼24 hour after activity breaks are initiated.

  • Combining activity breaks with continuous walking results in further improvements.

Background

Compared with prolonged sitting, regular activity breaks immediately lower postprandial glucose and insulin, but not triglyceride responses. Postprandial triglycerides can be lowered by physical activity but the effect is often delayed by ∼12 to 24 hours.

Objective

The objective of the study was to determine whether regular activity breaks affect postprandial triglyceride response in a delayed manner similar to physical activity.

Methods

In a randomized crossover trial, 36 adults (body mass index 23.9 kg/m2 [standard deviation 3.9]) completed four 2-day interventions: (1) prolonged sitting (SIT); (2) prolonged sitting with 30 minutes of continuous walking (60% VO2max), at the end of Day 1 (SIT + PAD1); (3) Sitting with 2 minutes of walking (60% VO2max) every 30 minutes (RAB); (4) A combination of the continuous walking and regular activity breaks in 2 and 3 above (RAB + PAD1). Postprandial plasma triglyceride, nonesterified fatty acids, glucose, and insulin responses were measured in venous blood over 5 hours on Day 2.

Results

Compared with SIT, both RAB (difference: −43.61 mg/dL·5 hours; 95% confidence interval [CI] −83.66 to −2.67; P = .035) and RAB + PAD1 (−65.86 mg/dL·5 hours; 95% CI −112.14 to −19.58; P = .005) attenuated triglyceride total area under the curve (tAUC). RAB + PAD1 produced the greatest reductions in insulin tAUC (−23%; 95% CI −12% to −31%; P < .001), whereas RAB resulted in the largest increase in nonesterified fatty acids (tAUC, 10.08 mg/dL·5 hours; 95% CI 5.60–14.84; P < .001). There was no effect on glucose tAUC (P = .290).

Conclusions

Postprandial triglyceride response is attenuated by regular activity breaks, when measured ∼24 hours after breaks begin. Combining regular activity breaks with 30 minutes of continuous walking further improves insulinemic and lipidemic responses.

Introduction

Sedentary behavior increases the risk of all-cause mortality, cardiovascular disease, and type II diabetes.1, 2 The association is attenuated by physical activity, but disappears only in those who exceed 60 to 70 minutes of physical activity per day.3 The pattern in which sedentary time is accumulated may also contribute to disease risk. Extended periods of sitting are associated with larger waist circumferences and higher 2-hour plasma glucose concentrations compared with similar durations of sedentary time regularly interrupted with activity.4, 5

The lack of an association between breaks in sedentary behavior and conventional risk factors for heart disease and diabetes, such as fasting insulin and cholesterol concentrations,4, 5 has focused attention on the possibility that the health effects of interrupting sedentary behavior may be mediated primarily through effects on postprandial metabolism. Indeed, current experimental evidence indicates that breaking prolonged sitting with ∼2 to 5 minutes of light or moderate intensity activity every 20 to 30 minutes lowers postprandial glucose and insulin responses, when the activity is performed during the postprandial period.6, 7, 8, 9, 10, 11, 12

Continuous or intermittent (3 × 10 minutes) bouts of physical activity exert strong effects on postprandial lipidemia, with the triglyceride-lowering effects occurring most consistently when measured 12 to 24 hours after the initiation of a physical activity pattern.13 However, to date, the results of the vast majority of studies indicate that aerobically based regular activity breaks (2–5 minutes every 20–30 minutes) do not affect postprandial triglyceride responses.6, 7, 9, 11, 12, 14 The discrepancy may arise because in the later studies, there is no time gap between the regular activity breaks and measurement of postprandial triglyceride concentrations; whereas in the former, the effects have been measured 12 to 24 hours after the initiation of activity.

It seems that regularly performed, short bouts of activity exert immediate effects on glucose and insulin, but effects on postprandial triglyceride concentrations may be delayed. Therefore, the aim of this study was to compare the effects of prolonged sitting and regular activity breaks (2 minutes every 30 minutes) with or without an additional 30 minutes of continuous physical activity on the afternoon of Day 1, on postprandial metabolism measured on the morning of Day 2.

Section snippets

Study design

This randomized, crossover trial took place at the University of Otago, in Dunedin, New Zealand, between June 2014 and November 2016. The trial was approved by the University of Otago Human Ethics Committee (approval number 13/112), and written informed consent was obtained from all participants before screening. The study is registered with the Australian New Zealand Clinical Trial Registry (ANZCTR12614000624684).

Participants

Participants were recruited through the distribution of e-mails and

Results

Of the 42 participants who were scheduled to participate, 6 withdrew after randomization; 2 did not complete the first session, a further 2 withdrew after completing the first session and 2 completed both the first and second sessions but did not complete the third (see Fig. 1). Thirty-six participants completed all 4 interventions sessions and were included in the final analysis. Participant characteristics at the time of recruitment are summarized in Table 1.

The mean percent of maximal

Discussion

Performing regular activity breaks—2 minutes of moderate intensity walking every 30 minutes—both the day before and during the postprandial measurement period, lowered postprandial triglyceride response, as measured by tAUC, in healthy, normal weight individuals. This effect occurred regardless of whether regular activity breaks were performed alone or in combination with a 30-minute continuous bout of physical activity the afternoon before the postprandial measurement period. Performing a

Conclusion

Requiring participants to perform regular activity breaks both the day before and during the postprandial period is a unique aspect of the study and more accurately reflects the pattern of activity that should be performed if avoidance of prolonged sitting is considered to be an important health message. The intervention that combines a 30-minute bout of continuous of physical activity with regular activity breaks most closely represents the pattern of activity currently being recommended in

Acknowledgement

The authors thank Glenna Paterson, Andrea Samson, and Angel Temple, Research Nurses (Department of Human Nutrition, University of Otago, Dunedin, New Zealand), who inserted the cannulas and assisted with the blood collection; Ashley Duncan and Michelle Harper, Laboratory Technicians (Department of Human Nutrition, University of Otago, Dunedin, New Zealand), who advised and assisted with the laboratory analyses; Grace Allen and Hannah Gentle, Research Assistants (Department of Human Nutrition,

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