Accumulating Physical Activity in Short or Brief Bouts for Glycemic Control in Adults With Prediabetes and Diabetes

Higher daily physical activity levels may facilitate pre-diabetes regression to normoglycemia: A longitudinal study among an Iranian population

The possible association of habitual physical activity (PA) and the risk of pre-diabetes (Pre-DM) progression to type 2 diabetes (T2D) or the chance of returning to normoglycemia was investigated. This cohort study included 1167 Pre-DM individuals (mean age of 53.5 years, and 45.3% men) who participated in the third phase of the Tehran Lipid and Glucose Study (2006-2008) and followed up to a median of 9 years. PA, including leisure time and job activities, was measured using a reliable and validated Iranian version of the Modifiable Activity Questionnaire and reported as metabolic equivalent (MET)-minutes per week. The odds ratios (ORs) and 95% confidence intervals (CIs) of incident T2D and returning to normoglycemia were estimated in relation to PA levels (i.e., per every 500 MET-minutes/week, or across categories of PA levels < 600 as a reference, 600-1500 and > 1500 MET-minutes/week). During the study follow-up, 39.0 % progressed to T2D, and 37.8% returned to normoglycemia. Compared to subjects with a PA < 600 MET-minutes/week, the chance of regression to normoglycemia increased by 58% [OR = 1.58, 95% CI = 1.03-2.40 ∼ relative risk (RR) = 1.32, 95% CI = 1.02-1.63] among the participants who had a PA > 1500 MET-minutes/week. We further noted that each 500 MET-min/week activity corresponded to an elevated chance of returning to normoglycemia by 5% (OR = 1.05, 95% CI = 1.01-1.11). The study's findings provided evidence that higher daily PA levels may facilitate Pre-DM regression to normoglycemia. The beneficial effect of PA in Pre-DM subjects needs to exceed the recommended levels (i.e., 600 MET-minutes/week).

Effects of accumulated versus continuous individualized exercise on postprandial glycemia in young adults with obesity

BACKGROUND

Elevated postprandial glucose (PPG) is an independent risk factor for cardiovascular disease. Post-meal exercise effectively reduces PPG concentrations. However, the effect of accumulated versus continuous post-meal exercise on PPG control remains unclear. This study aimed to investigate the effects of individualized accumulated or continuous exercise on PPG in young adults with obesity.

METHODS

Twenty young adults with obesity (11 males) completed three 4-h randomized crossover trials with 6-14-day washout periods: (1) sitting (SIT), (2) one 30-min walking bout (CONT), and (3) three 10-min walking bouts separated by 20-min resting (ACCU). Walking was initiated 20 min before individual PPG peak after breakfast, which was predetermined by continuous glucose monitoring. Blood samples were collected at 15-30 min intervals, and the 24-h glucose was monitored via continuous glucose monitoring.

RESULTS

The 4-h PPG incremental area under the curve (iAUC) was 12.1%±30.9% and 21.5%±21.5% smaller after CONT (P = 0.022) and ACCU (P < 0.001), respectively, than after SIT. PPG concentrations were lower during CONT at 30-60 min and during ACCU at 30-105 min after breakfast than during SIT (all P < 0.05). The 4-h plasma insulin and C-peptide iAUC, and mean amplitude of glycemic excursions were lower after CONT and ACCU than after SIT (all P < 0.05).

CONCLUSIONS

Both continuous and accumulated exercises reduced PPG, insulin, and C-peptide concentrations and improved glucose fluctuations. Accumulated exercise maintained lower PPG concentrations for a longer time than continuous exercise in young adults with obesity.

CLINICAL TRIAL INFORMATION

Clinical trial registration No. ChiCTR 2000035064, URL: http://www.chictr.org.cn/showproj.aspx?proj=56584; (registered July 29, 2020).HIGHLIGHTS Both continuous and accumulated walking lowered post-meal glucose, insulin and C-peptide levels and improved glucose fluctuation.Postprandial glucose was kept lower for a longer time in accumulated than continuous walking.Accumulated post-meal exercise (e.g. three 10-min bouts of walking) could be recommended as a feasible and practical alternative protocol for postprandial glucose control, especially for those who have difficulty performing sufficient exercise in one session.

The Effects of Accumulated Versus Continuous Exercise on Postprandial Glycemia, Insulin, and Triglycerides in Adults with or Without Diabetes: A Systematic Review and Meta-Analysis

BACKGROUND

Postprandial dysmetabolism, an important cardiovascular disease risk factor, can be improved by exercise. Further systematic review and meta-analysis is needed to compare the effects of accumulated exercise with a single session of energy-matched continuous exercise on postprandial glucose (PPG), insulin, and triglycerides in adults with or without diabetes.

METHODS

Eight electronic databases were searched on August 28, 2020, and updated on April 27, 2021. Eligible studies were randomized, quasi-randomized, or non-randomized controlled or crossover trials that evaluated the acute or longitudinal effects of accumulated exercise compared with a single session of energy-matched continuous exercise on PPG, postprandial insulin, and triglycerides in diabetic and non-diabetic adults. Same-day and second-morning effects were assessed separately for acute intervention studies. Subgroup analyses were conducted based on the number of exercise bouts (2-3 bouts or frequent brief bouts (e.g., 1-6 min) throughout the day at 20-60-min intervals (known as physical activity [PA] breaks, ≥ 5 bouts)), exercise intensity, and populations. Risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomized trials. Pooled effects were reported as standardized mean differences (SMD) and 95% CI using a random effects model.

RESULTS

Twenty-seven studies (635 participants) were included. A significant difference was found for same-day PPG control, which favored accumulated exercise over one bout of energy-matched continuous exercise (SMD - 0.36 [95%CI: (- 0.56, - 0.17)], P = 0.0002, I2 = 1%), specifically in accumulated exercise with PA breaks (SMD - 0.36 [95%CI: (- 0.64, - 0.08)], P = 0.01, I2 = 30%), low-moderate intensity exercise (SMD - 0.38 [(95%CI: (- 0.59, - 0.17)], P = 0.0005, I2 = 0%), and in non-diabetic populations (SMD - 0.36 [95%CI: (- 0.62, - 0.10)], P = 0.007, I2 = 16%). No differences were found for same-day postprandial insulin and triglycerides, and second-morning effects (postprandial or fasting glucose, insulin, and triglycerides) between different exercise patterns.

CONCLUSION

Compared with one session of continuous exercise, accumulated exercise-specifically in subgroups of PA breaks, low-moderate intensity exercises-produced greater acute effects on same-day PPG control for non-diabetic adults. There were no differences between continuous and accumulated patterns of exercise in terms of same-day postprandial insulin and triglycerides, and second-morning effects on all previously mentioned markers. The findings provide additional PA options for PPG control for individuals with limited time or exercise capacity to engage in PA in one session. Registration: PROSPERO (identification code: CRD42021251325).

Exercise Snacks: A Novel Strategy to Improve Cardiometabolic Health

We define exercise snacks as isolated ≤1-min bouts of vigorous exercise performed periodically throughout the day. We hypothesize that exercise snacks are a feasible, well-tolerated, and time-efficient approach to improve cardiorespiratory fitness and reduce the negative impact of sedentary behavior on cardiometabolic health. Efficacy has been demonstrated in small proof-of-concept studies. Additional research should investigate this novel physical activity strategy.