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SPECIAL COMMUNICATIONS: Corrigendum

Alternating Bouts of Sitting and Standing Attenuate Postprandial Glucose Responses—Corrigendum

Medicine & Science in Sports & Exercise: September 2020 - Volume 52 - Issue 9 - p 2058-2059
doi: 10.1249/MSS.0000000000002450
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The authors of “Alternating Bouts of Sitting and Standing Attenuate Postprandial Glucose Responses” (1) report an error in the calculation of the iAUC for glucose, insulin, and triglycerides. The area was not correctly calculated for the positive area above the basal (fasting value). As such, the authors have recalculated the positive incremental area under the curve above the fasting value and reanalyzed the data for glucose, insulin, and triglycerides. There was a small attenuation in the findings for glucose while the findings for insulin and triglycerides were unchanged. Also, the recalculation revealed a significant sex–condition interaction effect (P = 0.039), indicating that the mean percent change in glucose iAUC between conditions was higher in females than in male participants. The affected text sections are amended as noted below.

METHODS

The corrected text for page 2055 is as follows:

Positive iAUC was calculated (GraphPad Prism version 6) using the trapezoidal rule, ignoring the area beneath the fasting concentrations, during the 4-h postprandial period for glucose, insulin, and triglycerides.

RESULTS

The corrected text for page 2057 is as follows:

There was a significant effect of condition (in favor of the intervention condition) on plasma glucose concentrations (P = 0.043) but not on serum insulin nor plasma triglycerides. Adjusted mean glucose iAUC was lowered by 11% after the prolonged sitting interrupted with standing breaks condition (4.58 mM·h−1 (CI,3.07 –6.08)) relative to the prolonged sitting condition (5.14 mM·h−1 (CI, 3.63 –6.65)). There was a significant sex–condition interaction effect (P-value = 0.039). On stratification by sex, we found that the absolute difference in glucose iAUC between conditions was higher in females (−2.6 mM·h−1 (CI, −4.1, to −1.0)) compared to male participants (−0.18 mM·h−1 (CI −0.73 to 0.36)).

Corrected figures for the ratio of iAUC insulin: iAUC glucose are given in amended Table 2.

TU1
TABLE 2:
Condition and temporal effects of experimental conditions on biochemical and anthropometric characteristics of study participants.

Amended Figure 3 is shown below.

FU1
FIGURE 3:
Fasting and postprandial plasma glucose (A), serum insulin (B), and plasma triglyceride (C) concentrations measured on assessment days (days 1 and 5) during the prolonged sitting at work condition (black triangle) and prolonged sitting interrupted with standing breaks at work condition (white circle). Data in analyte time curves are presented as mean ± SEM. Condition effects (4-h iAUC) adjusted for time (days 1 and 5) data are presented as marginal means ± 95% CI (adjusted for condition, time, condition order, baseline predrink values for the outcome of interest, sex, age, waist circumference, and dietary intake during the condition (kJ·d−1)). *Significantly different from prolonged sitting at work condition (black triangle), P = 0.043.

DISCUSSION

The corrected text for page 2058 is as follows:

Our findings extend the recent experimental evidence that breaking up prolonged sitting with walking bouts acutely improves postprandial glucose metabolism (8,28) by providing novel insights into the specific effects of intermittent standing. To date, only one other study has investigated the acute effects of intermittent standing bouts on glucose and lipid metabolism under laboratory conditions (26). The 2-d study involving 15 healthy normolipidemic males found no postcondition improvement in postprandial glucose, insulin, and triglyceride levels after 1 d of prolonged sitting with a 45-min standing bout (without movement) every hour for 6 h (total of 4.5 h standing) compared with that after prolonged sitting only. In the current study, a modest albeit statistically significant 11% reduction in glucose iAUC during the prolonged sitting with standing breaks condition was observed. Differences in study population and design may have contributed to the disparate findings because our study included overweight, middle-age sedentary adults who were permitted to engage in spontaneous light ambulation during standing bouts as opposed to young, healthy males who were required to stand in a fixed position (26).

Note that the outcomes of these revised calculations do not change the interpretations and conclusions of the original article.

REFERENCE

1. Thorp AA, Kingwell BA, Sethi P, Hammond L, Owen N, Dunstan DW. Alternating bouts of sitting and standing attenuate postprandial glucose responses. Med Sci Sports Exerc. 2014;46(11):2053–61.
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