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).

Context Prolonged sitting elevates postprandial metabolic markers, resulting in increased risks of cardiovascular diseases and type 2 diabetes. Interrupting prolonged sitting may reduce these risks. However, more information is needed to understand the patterns of interrupting prolonged sitting to obtain metabolic health benefits. Objective This study examined the effects of interrupting prolonged sitting with different intensities and durations of walking with an equivalent energy expenditure on postprandial metabolic responses in young Chinese men with central obesity. Design A randomized crossover experimental trial was conducted. Setting Participants underwent three 6-hour experiments with a 7-day washout period between each experiment: prolonged sitting, 3 min of light-intensity walking every 30 minutes, and 1.5 minutes of moderate-intensity walking every 30 minutes. Participants and Samples Baseline (fasting) and 6-hour postprandial metabolic glucose and lipid levels were analyzed among 18 young Chinese men with central obesity. Main Outcome Measures Generalized estimating equations (adjusted for the potential confounders explaining residual outcome variance (body mass index) and age), trial order, preprandial values, and lead-in activity) were used, and the incremental areas under the curve (iAUC) of each outcome were compared between prolonged sitting and interrupted prolonged sitting conditions. Results Compared with prolonged sitting, both interrupting prolonged sitting conditions reduced the iAUCs for glucose (P < .05) but not insulin, C-peptide, triglycerides, or nonesterified fatty acids. Conclusions Both conditions of interrupted prolonged sitting reduced postprandial glucose concentrations in young Chinese men with central obesity when the energy expenditure was equivalent.

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. 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. 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). 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.

Background: This systematic review and meta-analysis examined the synergistic impact of time-restricted feeding (TRF) combined with resistance training (RT) (TRF + RT) on body composition and metabolic health in adults, contrasting it with habitual eating patterns (CON) and RT (CON + RT). Methods: Adhering to PRISMA guidelines, five databases were searched up to 28 April 2024. Randomized controlled trials or crossover trials assessing the effects of TRF + RT for at least 4 weeks in adults were selected. Data were pooled as standardized mean differences (SMDs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). The risk of bias was evaluated using the revised Cochrane risk-of-bias tool. Results: Seven studies with 164 participants were included in the final analysis. TRF + RT significantly reduced body mass (WMD −2.90, 95% CI: −5.30 to −0.51), fat mass (WMD −1.52, 95% CI: −2.30 to −0.75), insulin (SMD −0.72, 95% CI: −1.24 to −0.21), total cholesterol (WMD −9.44, 95% CI: −13.62 to −5.27), low-density lipoprotein cholesterol (LDL-C) (WMD −9.94, 95% CI: −13.47 to −6.41), and energy intake (WMD −174.88, 95% CI: −283.79 to −65.97) compared to CON + RT. No significant changes were observed in muscle mass, strength, or other metabolic markers. Conclusions: TRF + RT, in contrast to CON + RT, significantly improved body composition, insulin, and cholesterol levels without affecting muscle mass or strength.

Context Recent studies suggest that light-intensity physical activity may enhance cardiometabolic health and reduce mortality risk in adults. However, more information is required to understand the patterns of light-intensity physical activity and postprandial cardiometabolic health. Objective This study examined the effects of different light-intensity walking patterns on postprandial cardiometabolic responses in young obese adults. Design A randomized crossover trial was conducted. Setting The study was conducted in the laboratory. Participants The study analyzed baseline (fasting) and 6-hour postprandial concentrations of glucose, insulin, triglycerides, and blood pressure (BP) in 16 young obese adults. Interventions Participants underwent four 7-hour experimental conditions with a 7–20-day washout period: uninterrupted sitting (SIT), 30-minute light-intensity walking (EX+SIT), 3-minute light-intensity walking every 30 minutes (BR), and 30-minute light-intensity walking with 3-minute light-intensity walking every 30 minutes (EX+BR). Main Outcome Measures Incremental areas under the curve (iAUC) for each outcome and average BP were compared between SIT and walking conditions. Results Compared with SIT, all walking conditions reduced iAUCs for glucose and average diastolic BP (all p<0.05). Only EX+SIT and EX+BR reduced iAUCs for insulin (p0.05). Conclusions All patterns of light-intensity walking reduced postprandial glucose concentrations and diastolic BP in young obese adults, suggesting benefits for glycemic control. Continuous 30-minute light-intensity walking alone, or combined with brief 3-min bouts also attenuated postprandial insulin concentrations, highlighting light-intensity walking as a promising strategy for improving cardiometabolic health in young obese adults.

Recent advancements in Continuous Glucose Monitoring (CGM) technology provide a novel solution for monitoring dynamic glucose fluctuations during endurance exercise, enabling personalized carbohydrate refueling strategies. However, direct evidence demonstrating its superiority over traditional refueling guidelines has been lacking. This exploratory study compared a CGM-informed protocol with a traditional interval-based (TRAD) carbohydrate refueling protocol on endurance exercise responses. Twelve healthy, non-diabetic males (age = 32.3 ± 6.3 years) participated in two trials involving 75 minutes of continuous cycling at 50% peak power output, with the two carbohydrate refueling protocols implemented in a randomized, crossover order. In the TRAD protocol, participants received standard carbohydrate solutions at regular 15-min intervals, while replenishment timing in the CGM-informed protocol was guided by real-time glucose trends, particularly during declines. No significant differences were observed in heart rate, blood lactate, or perceived exertion between conditions (all p > 0.05). However, CGM-informed protocol displayed a lower coefficient of variation of glucose levels (8.82 ± 4.68%) than the TRAD protocol (11.95 ± 3.41%, Cohen's d = 0.76, p = 0.013), indicating a steadier blood glucose trend. The mean 75-minute interstitial glucose total area under the curve was significantly lower for the CGM-informed protocol (423.4 ± 39.1 mmol·min·L-1), compared to the TRAD protocol (448.6 ± 38.2 mmol·min·L-1, Cohen's d = 0.65, p = 0.008). While the CGM-informed protocol did not demonstrate beneficial effects on physiological responses over the TRAD protocol, it may aid in stabilizing glucose levels during prolonged endurance exercise. Further research is warranted to explore the applications of personalized carbohydrate refueling strategy based on CGM technology on athletic performance across various exercise protocols. .