Does breaking up moderate intensity continuous exercise into accumulated bouts improve postprandial metabolic outcomes in older adults?
Faculty Advisor Name
Dr. Stephanie P. Kurti-Luden
Department
Department of Kinesiology
Description
Intro: In the United States, there is a high incidence of CVD prevalence in older adults, low levels of chronic physical activity, and poor dietary habits. It is imperative to determine an optimal dose of exercise that is attainable and may mitigate adverse postprandial (post-meal) responses, which are strong predictors of cardiovascular disease risk. Exercise interventions with higher intensities, longer total durations, and/or greater energy expenditures seem most effective in attenuating postprandial metabolic markers such as triglycerides (TRG), glucose (GLU), and metabolic load index (MLI: summation of GLU and TRG), but the time and energy demands may be unrealistic for older populations. While several studies have broken up continuous exercise into accumulated bouts, this study is the first to our knowledge to assess whether accumulated exercise to expend 25% of the calories consumed in a high-fat meal (HFM) will lower postprandial TRG, GLU, and MLI, compared to continuous exercise, in older adults.
Methods: Ten older adults (n=10, 6F, 4M) participated in a partially randomized, crossover design with three conditions following a HFM: 1) sedentary for 6 hours (HFM) 2) one continuous walking bout (~30 minutes) (HFM+EX), and 3) breaking up the continuous exercise into 10 equal accumulated bouts (~3 minutes) (ACCU+EX). The HFM was Marie Callender's Chocolate Satin Pie (57% fat; 37% CHO) consumed at 12 kcal/kg of body weight. Both exercise conditions expended 25% of the calories consumed. Mixed effects models were used to determine time, condition, and interaction effects on TRG, GLU, and MLI.
Results: There was a significant increase in TRG post-HFM (p < 0.05), however, TRG were significantly lower in the HFM+EX compared to the HFM condition over time (p=0.02). HFM+EX exhibited lower TRG at 240 min (p=0.03), 300 min (p<0.01), and 360 min (p=0.03) compared to HFM. Both HFM+EX and ACCU+EX had significant effects on GLU over time (p<0.003). Specifically, at time point 60 min, both HFM+EX and ACCU+EX were significantly lower than HFM alone (p=0.03, p=0.02). At time point 120 min, HFM+EX was significantly higher than both HFM (p<0.01) and ACCU+EX (p=0.01). MLI was significantly lower in the HFM+EX condition compared to HFM at time points 240 min (p=0.02), 300 min (p<0.01), and 360 min (p=0.03). There was a trend towards significance for a lower MLI in the ACCU+EX condition compared to the HFM alone (p=0.07).
Conclusion: Following a HFM, continuous exercise with an energy expenditure of 25% of calories consumed is effective at lowering TRG, GLU, and MLI. Accumulated bouts of exercise throughout the day are effective at reducing and maintaining GLU levels and do not appear to reduce postprandial TRG. However accumulated bouts may lower MLI, but have a lower attenuation compared with continuous exercise. It does appear that walking to expend 25% of calories consumed either continuously or throughout the day can mitigate postprandial metabolic outcomes, potentially reducing disease risk in older adults.
Abbreviations:
HFM: high fat meal
TRG: triglycerides
GLU: glucose
MLI: metabolic load index
EX: exercise
Does breaking up moderate intensity continuous exercise into accumulated bouts improve postprandial metabolic outcomes in older adults?
Intro: In the United States, there is a high incidence of CVD prevalence in older adults, low levels of chronic physical activity, and poor dietary habits. It is imperative to determine an optimal dose of exercise that is attainable and may mitigate adverse postprandial (post-meal) responses, which are strong predictors of cardiovascular disease risk. Exercise interventions with higher intensities, longer total durations, and/or greater energy expenditures seem most effective in attenuating postprandial metabolic markers such as triglycerides (TRG), glucose (GLU), and metabolic load index (MLI: summation of GLU and TRG), but the time and energy demands may be unrealistic for older populations. While several studies have broken up continuous exercise into accumulated bouts, this study is the first to our knowledge to assess whether accumulated exercise to expend 25% of the calories consumed in a high-fat meal (HFM) will lower postprandial TRG, GLU, and MLI, compared to continuous exercise, in older adults.
Methods: Ten older adults (n=10, 6F, 4M) participated in a partially randomized, crossover design with three conditions following a HFM: 1) sedentary for 6 hours (HFM) 2) one continuous walking bout (~30 minutes) (HFM+EX), and 3) breaking up the continuous exercise into 10 equal accumulated bouts (~3 minutes) (ACCU+EX). The HFM was Marie Callender's Chocolate Satin Pie (57% fat; 37% CHO) consumed at 12 kcal/kg of body weight. Both exercise conditions expended 25% of the calories consumed. Mixed effects models were used to determine time, condition, and interaction effects on TRG, GLU, and MLI.
Results: There was a significant increase in TRG post-HFM (p < 0.05), however, TRG were significantly lower in the HFM+EX compared to the HFM condition over time (p=0.02). HFM+EX exhibited lower TRG at 240 min (p=0.03), 300 min (p<0.01), and 360 min (p=0.03) compared to HFM. Both HFM+EX and ACCU+EX had significant effects on GLU over time (p<0.003). Specifically, at time point 60 min, both HFM+EX and ACCU+EX were significantly lower than HFM alone (p=0.03, p=0.02). At time point 120 min, HFM+EX was significantly higher than both HFM (p<0.01) and ACCU+EX (p=0.01). MLI was significantly lower in the HFM+EX condition compared to HFM at time points 240 min (p=0.02), 300 min (p<0.01), and 360 min (p=0.03). There was a trend towards significance for a lower MLI in the ACCU+EX condition compared to the HFM alone (p=0.07).
Conclusion: Following a HFM, continuous exercise with an energy expenditure of 25% of calories consumed is effective at lowering TRG, GLU, and MLI. Accumulated bouts of exercise throughout the day are effective at reducing and maintaining GLU levels and do not appear to reduce postprandial TRG. However accumulated bouts may lower MLI, but have a lower attenuation compared with continuous exercise. It does appear that walking to expend 25% of calories consumed either continuously or throughout the day can mitigate postprandial metabolic outcomes, potentially reducing disease risk in older adults.
Abbreviations:
HFM: high fat meal
TRG: triglycerides
GLU: glucose
MLI: metabolic load index
EX: exercise