Fitness Moderates Glycemic Responses to Sitting and Light Activity Breaks.
Study Goal
The researchers aimed to determine whether cardiorespiratory fitness (CRF) influences postprandial glycemia during prolonged sitting and whether light walking breaks could mitigate these effects.
Results Summary
Light walking breaks significantly reduced postprandial blood glucose and insulin levels, with the greatest benefits observed in individuals with low CRF. The effect diminished in those with higher CRF.
Population
34 adults (18 women, 16 men; mean age 40 ± 9 years, BMI 24.5 ± 3 kg/m²).
Effective Dosage
5-minute light walking bouts every 30 minutes.
Duration
7.5-hour experimental conditions.
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Sitting interspersed with 5 min light walking bouts every 30 min | decrease | blood glucose iAUC | Thirty-four adults (18 women; 16 men; mean ± SD age, 40 ± 9 yr, body mass index, 24.5 ± 3 kg·m) | from 3.89 ± 0.7 to 2.51 ± 0.7 mmol·L·h | reduced | #1 |
Sitting interspersed with 5 min light walking bouts every 30 min | decrease | insulin iAUC | Thirty-four adults (18 women; 16 men; mean ± SD age, 40 ± 9 yr, body mass index, 24.5 ± 3 kg·m) | from 241 ± 46 to 156 ± 24 mU·L·h | reduced | #2 |
Sitting interspersed with 5 min light walking bouts every 30 min | decrease | blood glucose iAUC | a man at the 25th centile of CRF (42.5 mL·kg·min) | from 5.80 to 2.98 mmol·L·h | reduced | #3 |
Sitting interspersed with 5 min light walking bouts every 30 min | decrease | blood glucose iAUC | a man at the 75th centile of CRF (60.5 mL·kg·min) | from 1.99 to 1.78 mmol·L·h | reduced | #4 |
Sitting interspersed with 5 min light walking bouts every 30 min | increase | metabolic benefit | Individuals with low CRF | - | gained the most metabolic benefit | #5 |
PURPOSE: This study aimed to experimentally determine whether cardiorespiratory fitness (CRF) modifies postprandial glycemia during prolonged sitting and investigated the potentially blunting influence this may have on the benefits of interrupting postprandial sitting time with light activity breaks. METHODS: Thirty-four adults (18 women; 16 men; mean ± SD age, 40 ± 9 yr, body mass index, 24.5 ± 3 kg·m) undertook two 7.5-h experimental conditions in a randomized order: 1) Prolonged sitting; 2) Sitting interspersed with 5 min light walking bouts every 30 min. Blood samples were obtained while fasting and postprandially after ingestion of two identical meals. Incremental area under the curve (iAUC) was calculated for glucose and insulin throughout experimental conditions. Maximal exercise testing quantified peak oxygen consumption (V˙O2 peak) as a measure of CRF. A repeated-measures ANOVA investigated whether V˙O2 peak modified glucose and insulin iAUC between conditions. RESULTS: Breaking sedentary time with light walking breaks reduced blood glucose iAUC from 3.89 ± 0.7 to 2.51 ± 0.7 mmol·L·h (P = 0.015) and insulin iAUC from 241 ± 46 to 156 ± 24 mU·L·h (P = 0.013) after adjustment for V˙O2 peak and sex. A significant interaction between treatment response and V˙O2 peak was observed for glucose (P = 0.035), but not insulin (P = 0.062), whereby the treatment effect reduced with higher CRF. Average blood glucose iAUC responses for a man at the 25th centile of CRF within our cohort (42.5 mL·kg·min) went from 5.80 to 2.98 mmol·L·h during the prolonged sitting and light walking break conditions respectively, whereas average responses for a man at the 75th centile of CRF (60.5 mL·kg·min) went from 1.99 to 1.78 mmol·L·h. Similar trends were observed for women. CONCLUSIONS: Individuals with low CRF gained the most metabolic benefit from breaking prolonged sitting with regular bouts of light walking.