Prolonged standing reduces fasting plasma triglyceride but does not influence postprandial metabolism compared to prolonged sitting

Physical inactivity causes exercise resistance of fat metabolism: harbinger or culprit of disease?

Physical inactivity is the fourth leading cause of death in the world. It is associated with myriad diseases and premature death. Two possible contributing factors are postprandial lipidaemia (PPL), which accelerates atherosclerosis, and impaired whole-body fat oxidation, which contributes to obesity. Acute exercise in physically active people is effective for increasing whole body fat oxidation and lowering PPL the next morning. However, in people who have low physical activity (<8000 steps/day), an acute bout of exercise (1 h at 62% maximal oxygen consumption) has no effect on increasing fat oxidation or reducing PPL ('exercise resistance'). The acute harms of inactivity are not due to the lack of exercise and are more powerful than the benefits of exercise, at least regarding fat metabolism. The increase in mortality with reduced daily steps is remarkably steep. Low background steps/day also impair the metabolic adaptations to short-term endurance training, suggesting that the ills of inactivity extend beyond fat metabolism. 'Exercise resistance' with inactivity could be a culprit, causing atherosclerosis, or maybe also a harbinger (impaired fat oxidation) of more widespread diseases. Recommendations regarding the amount of moderate to vigorous exercise needed for health should factor in the amount of background activity (i.e. ∼8000 steps/day) necessary to avoid 'exercise resistance'.

Long sedentary time is associated with worsened cardiometabolic risk factors among university employees in Eastern Ethiopia

Sedentary time is associated with increased risks of detrimental health outcomes. Prolonged sedentary time associates with cardiometabolic risk factors and increased mortality regardless of physical activity. Therefore, the purpose of this study was to examine the associations of sedentary time and cardiometabolic risk factors among university employees in Eastern Ethiopia. A cross-sectional study was conducted among 1200 participants. Data were collected using the World Health Organization STEPS survey instrument, and sedentary behavior questionnaire in hour per day. Sedentary time is the time spent for any duration (minutes per day or hours per day) by considering a local context. Study participants were asked how many minutes or hours they spent in sedentary time at work, their leisure time and in transportation. Finally, the total sedentary time was calculated by the sum of the individual spent in sedentary time at work, leisure, and transportation. Cardiometabolic risk factors were assessed with blood samples analysis and anthropometric measurements. The associations between sedentary time and cardiometabolic risk factors were examined using linear regression models. An adjusted coefficient (β) with the 95% confidence interval (CI) was used to report the results. p value < 0.05 was considered for statistical significance. The mean age of the study participants were (35 ± 9.4 years). Almost half of the study participants, 566 (48.6) were women and 598 (51.4%) were men. As the total sedentary time was increased by one unit, the body mass index increased by β = 0.61; (95% CI 0.49-0.71),waist circumference increased by β = 1.48; (95% CI 1.14-1.82), diastolic blood pressure increased by β = 0.87; (95% CI 0.56-1.18), systolic blood pressure increased by β = 0.95; (95% CI 0.45-1.48), triglycerides increased by β = 7.07; (95% CI 4.01-10.14), total cholesterol increased by β = 3.52; (95% CI 2.02-5.02), fasting plasma glucose increased by β = 4.15; (95% CI 5.31-4.98) and low-density lipoprotein cholesterol increased by β = 2.14; (95% CI 0.96-3.33) with the effects of other variables maintain constant. These findings depict the need for strategies that policymakers should promote physical activity and encouraging the breaking up of prolonged sedentary time to reduce cardiometabolic risk factors among university employees in Ethiopia.

Effect of Prior Exercise on Postprandial Lipemia: An Updated Meta-Analysis and Systematic Review

The purpose of this systematic review was to synthesize the results from current literature examining the effects of prior exercise on the postprandial triglyceride (TG) response to evaluate current literature and provide future direction. A quantitative review was performed using meta-analytic methods to quantify individual effect sizes. A moderator analysis was performed to investigate potential variables that could influence the effect of prior exercise on postprandial TG response. Two hundred and seventy-nine effects were retrieved from 165 studies for the total TG response and 142 effects from 87 studies for the incremental area under the curve TG response. There was a moderate effect of exercise on the total TG response (Cohen's d = -0.47; p < .0001). Moderator analysis revealed exercise energy expenditure significantly moderated the effect of prior exercise on the total TG response (p < .0001). Exercise modality (e.g., cardiovascular, resistance, combination of both cardiovascular and resistance, or standing), cardiovascular exercise type (e.g., continuous, interval, concurrent, or combined), and timing of exercise prior to meal administration significantly affected the total TG response (p < .001). Additionally, exercise had a moderate effect on the incremental area under the curve TG response (Cohen's d = -0.40; p < .0001). The current analysis reveals a more homogeneous data set than previously reported. The attenuation of postprandial TG appears largely dependent on exercise energy expenditure (∼2 MJ) and the timing of exercise. The effect of prior exercise on the postprandial TG response appears to be transient; therefore, exercise should be frequent to elicit an adaptation.

Inactivity Causes Resistance to Improvements in Metabolism After Exercise

Prolonged sitting prevents a 1-h bout of running from improving fat oxidation and reducing plasma triglycerides. This "exercise resistance" can be prevented by taking 8500 steps·d-1 or by interrupting 8 h of sitting with hourly cycle sprints. We hypothesize that there is an interplay between background physical activity (e.g., steps·d-1) and the exercise stimuli in regulating some acute and chronic adaptations to exercise.

Exercise to lower postprandial lipemia: why, when, what and how

We review recent findings on the ability of exercise to lower postprandial lipemia (PPL). Specifically, we answer why exercise is important in lowering PPL, when it is most effective to exercise to achieve this, what the preferred exercise is and how exercise reduces PPL. Most findings confirm the power of exercise to lower PPL, which is an independent risk factor for cardiovascular disease. Exercise is most effective when performed on the day preceding a high- or moderate-fat meal. This effect lasts up to approximately two days; therefore, one should exercise frequently to maintain this benefit. However, the time of exercise relative to a meal is not that important in real-life conditions, since one consumes several meals during the day; thus, an exercise bout will inevitably exert its lowering effect on PPL in one or more of the subsequent meals. Although moderate-intensity continuous exercise, high-intensity intermittent exercise (HIIE), resistance exercise and accumulation of short bouts of exercise throughout the day are all effective in lowering PPL, submaximal, high-volume interval exercise seems to be superior, provided it is tolerable. Finally, exercise reduces PPL by both lowering the rate of appearance and increasing the clearance of triacylglycerol-rich lipoproteins from the circulation.

Nonexercise Activity Thermogenesis-Induced Energy Shortage Improves Postprandial Lipemia and Fat Oxidation

(1) Background: This study investigated the effect of nonexercise activity thermogenesis on postprandial triglyceride (TG) concentrations; (2) Methods: Ten healthy males completed a sedentary trial (ST) and a physical activity trial (PA) in a random order separated by at least 7 days. After each intervention on day 1, the participants consumed a high-fat test meal on the next day. The blood samples and gas sample were observed in the fasted state and for 4 h after consuming the oral fat tolerance test; (3) Results: The postprandial TG concentrations of total (AUC) (p = 0.008) and incremental area under the curve (IAUC) (p = 0.023) in the plasma of participants in the PA trial were significantly lower than those in the plasma of participants in the ST trial. The postprandial fat oxidation rate AUC of the PA trial was significantly higher than that of the ST trial (p = 0.009); (4) Conclusions: The results of this study indicated that nonexercise energy expenditure decrease the postprandial TG concentration and increase the fat oxidation the next day.