The effect of exercise intensity and excess postexercise oxygen consumption on postprandial blood lipids in physically inactive men

THE EFFECT OF HIGH-INTENSITY INTERVAL TRAINING ON POST-EXERCISE OXYGEN CONSUMPTION: A META-ANALYSIS

ABSTRACT Introduction: The objective of this study was to present a systematic review and meta-analysis to compare total excess post-exercise oxygen consumption (EPOC) for two training intervention models in healthy individuals, and the secondary objective was to understand whether oxygen consumption after exercise could really promote a meaningful help. Design: To design a meta-analysis review to compare two training intervention models (experimental: high-intensity interval training; and control: continuous moderate-intensity) and their effects on total EPOC in healthy individuals. Participants: Seventeen studies were considered to be of good methodological quality and with a low risk of bias. Methods: Literature searches were performed using the electronic databases with no restriction on year of publication. The keywords used were obtained by consulting Mesh Terms (PubMed) and DeCS (BIREME Health Science Descriptors). Results: The present study findings showed a tendency (random-effects model: 0.87, 95%-CI [0.35,1.38], I2=73%, p<0.01) to increase EPOC when measured following high-intensity interval training. Conclusions: Our study focused on the analysis of high- and moderate-intensity oxygen uptake results following exercise. Despite the growing popularity of high-intensity interval training, we found that the acute and chronic benefits remain limited. We understand that the lack of a standard protocol and standard training variables provides limited consensus to determine the magnitude of the EPOC. We suggest that longitudinal experimental studies may provide more robust conclusions. Another confounding factor in the studies investigated was the magnitude (time in minutes) of VO2 measurements when assessing EPOC. Measurement times ranged from 60 min to 720 min. Longitudinal studies and controlled experimental designs would facilitate more precise measurements and correct subject numbers would provide accurate effect sizes. Systematic reviewb of Level II studies.

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.

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.

Effects of High-Intensity Interval Exercise and Acute Partial Sleep Deprivation on Cardiac Autonomic Modulation

Sleep deprivation in healthy adults has been associated with disrupted autonomic nervous system function, which in turn has been linked to cardiovascular health. High-intensity interval exercise (HIIE) may affect both sleep and cardiac autonomic modulation. Purpose: To investigate the impact of acute partial sleep deprivation on autonomic cardiac regulation before and after an acute bout of HIIE and the length of time for the autonomic system to return to resting levels. Methods: Fifteen healthy males with body mass index (BMI) of 25.8 ± 2.7 kg·m^-2 and age 31 ± 5 y participated in a reference sleep (~9.5 hr) with no HIIE (RS), a reference sleep with HIIE (RSX), and an acute partial sleep deprivation (~3.5 hr) with HIIE (SDX). HIIE was performed in 3:2 intervals at 90% and 40% of VO₂ reserve. Autonomic regulation through HRV selected time and frequency domain indices were recorded the night before, the morning of the next day, 1 hr-, 2 hr-, 4hr-, and 6-hr post-exercise. Results: HIIE performed in a 3:2 W:R ratio decreased the HRV (p < .05) at 1-hr post exercise and it took up to 4 hr to return to baseline levels. Parasympathetic related HRV indices increased the morning of the next day for SDX (p < .05). Acute partial sleep deprivation and HIIE did not modify the HRV responses compared to reference sleep and HIIE. Conclusion: HRV disturbance typically seen in responses to an acute episode of HIIE is not influenced by acute partial sleep deprivation.

High-Intensity Interval Exercise Performance and Short-Term Metabolic Responses to Overnight-Fasted Acute-Partial Sleep Deprivation

People practicing high-intensity interval exercise (HIIE) fasted during the morning hours under a lack of sleep. Such a habit may jeopardize the health benefits related to HIIE and adequate sleep. Fifteen habitually good sleeper males (age 31.1 ± 5.3 SD year) completed on a treadmill two isocaloric (500 kcal) HIIE sessions (3:2 min work:rest) averaged at 70% VO2reserve after 9-9.5 h of reference sleep exercise (RSE) and after 3-3.5 h of acute-partial sleep deprivation exercise (SSE). Diet and sleep patterns were controlled both 1 week prior and 2 days leading up to RSE and SSE. HIIE related performance and substrate utilization data were obtained from the continuous analysis of respiratory gases. Data were analyzed using repeated measures ANOVA with the baseline maximum oxygen uptake (VO2max) and body fat percentage (BF%) as covariates at p < 0.05. No difference was observed in VO2max, time to complete the HIIE, VE, RER, CHO%, and FAT% utilization during the experimental conditions. Whether attaining an adequate amount of sleep or not, the fasted HIIE performance and metabolism were not affected. We propose to practice the fasted HIIE under adequate sleep to receive the pleiotropic beneficial effects of sleep to the human body.

Acute partial sleep deprivation and high-intensity interval exercise effects on postprandial endothelial function

PURPOSE

Acute-total and chronic-partial sleep deprivation increase the risks for cardiovascular disease (CVD). Cardiovascular function assessed by flow mediated dilation (FMD) is reduced after sleep deprivation. High-intensity interval exercise (HIIE) improves postprandial FMD. Sleep-deprived individuals may practice HIIE followed by a high-fat breakfast. This study investigated the acute-partial sleep deprivation (APSD) and HIIE interaction on postprandial FMD.

METHODS

Fifteen healthy males (age 31 ± 5 years) participated in: (a) reference sleep (~ 9.5 h) with no HIIE (RS), (b) RS and HIIE (RSX), and (c) APSD and HIIE (SSX). HIIE was performed in 3:2 min intervals at 90% and 40% of VO₂ reserve. FMD was assessed the night before (D1), the morning of the next day (D2), 1 h (1hrPE) and 4 h post HIIE (4hrPE).

RESULTS

FMD% change was lower at RS compared to both RSX (F_1,14 = 23.96, p < 0.001, η² = 0.631) and SSX (F_1,14 = 4.8, p = 0.47, η² = 0.253) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = 0.2, p = 0.889, η² = 0.001), but SSX elicited greater FDM responses. Absolute FMD change was lower at RS compared to both RSX (F_1,14 = 21.5, p < 0.001, η² = 0.606) and SSX (F_1,14 = 7.01, p = 0.019, η² = 0.336) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = .03, p = 0.858, η² = 0.002), but SSX elicited greater FDM responses.

CONCLUSIONS

HIIE short-term effects on cardiovascular function remain cardioprotective even after an acute-partial sleep deprivation.

Exercise and postprandial lipemia: effects on vascular health in inactive adults

BACKGROUND

There is evidence to suggest that postprandial lipemia are is linked to the impairment of endothelial function, which is characterized by an imbalance between the actions of vasodilators and vasoconstrictors. The aim of this study was to determine the effects of a 12-week high-intensity training (HIT) and moderate continuous training (MCT) protocol on postprandial lipemia, vascular function and arterial stiffness in inactive adults after high-fat meal (HFM) ingestion.

METHODS

A randomized clinical trial was conducted in 20 healthy, inactive adults (31.6 ± 7.1 years). Participants followed the two exercise protocols for 12 weeks. To induce a state of postprandial lipemia (PPL), all subjects received a HFM. Endothelial function was measured using flow-mediated vasodilation (FMD), normalized brachial artery FMD (nFMD), aortic pulse wave velocity (PWV) and augmentation index (AIx). Plasma total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides and glucose were also measured.

RESULTS

The effects of a HFM were evaluated in a fasted state and 60, 120, 180, and 240 min postprandially. A significant decrease in serum glucose between 0 min (fasted state) and 120 min postprandially was found in the HIT group (P = 0.035). Likewise, FMD (%) was significantly different between the fasted state and 60 min after a HFM in the HIT group (P = 0.042). The total cholesterol response expressed as area under curve (AUC)(0-240) was lower following HIT than following MCT, but no significant differences were observed (8%, P > 0.05). Similarly, triglycerides AUC(0-240) was also lower after HIT compared with MCT, which trended towards significance (24%, P = 0.076). The AUC(0-240) for the glucose response was significantly lower following HIT than MCT (10%, P = 0.008). FMD and nFMD AUC(0-240) were significantly higher following HIT than following MCT (46.9%, P = 0.021 and 67.3%, P = 0.009, respectively). PWV AUC(0-240) did not differ following between the two exercise groups (2.3%, P > 0.05).

CONCLUSIONS

Supervised exercise training mitigates endothelial dysfunction and glucose response induced by PPL. Exercise intensity plays an important role in these protective effects, and medium-term HIT may be more effective than MCT in reducing postprandial glucose levels and attenuating vascular impairment.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02738385 Date of registration: April 14, 2016.