A new study published in The Journal of Nutrition sheds light on the optimal timing of exercise initiation relative to meal consumption on postprandial blood glucose. 

Exercise initiated after a meal favorably impacts glycemic control in individuals with type 2 diabetes, although the optimal timing relative to meal consumption remains unclear.  The glucose responses after eating vary between individuals, suggesting that the optimal exercise timing to lower glucose may be different between individuals. Few studies have directly compared the effect of post-meal exercise timing on glycemic management using an individualized approach.  

To investigate the optimal timing of exercise on postprandial glucose, Stephen Wong (The Chinese University of Hong Kong) and colleagues used continuous glucose monitoring devices to estimate blood glucose peak time after eating in 20 healthy male adults with overweight or obesity.  Utilizing a randomized controlled crossover design, subjects completed three 240-minute trials: 1) sitting, 2) walking initiated at each participant’s postprandial glucose peak time, and 3) walking initiated 20 minutes before each participant’s postprandial glucose peak time. Postprandial responses for blood glucose, insulin, and C-peptide concentrations were measured for each trial.

Compared with sitting, exercise initiated 20 minutes prior to individualized postprandial glucose peak time lowered postprandial glucose, insulin, and C-peptide (a substance that reflects how much insulin is produced). The greatest reductions were observed in individuals with body mass index values >27.5 kg/m2, and those with a relatively higher postprandial glucose levels during resting. 

Furthermore, postprandial insulin and C-peptide concentrations were lower when exercise was initiated 20 minutes prior to the postprandial glucose peak compared with the same amount of exercise initiated at individualized glucose peak.  A greater understanding of the impact of exercise timing relative to meal consumption on glycemic regulation may help further optimize the metabolic benefits of exercise.

References

Zhang X, Wongpipit W, Sun F, Sheridan S, Huang WYJ, Sit CHP, Wong SHS.  Walking Initiated 20 Minutes before the Time of Individual Postprandial Glucose Peak Reduces the Glucose Response in Young Men with Overweight or Obesity: A Randomized Crossover Study. The Journal of Nutrition, Volume 151, Issue 4, April 2021, Pages 866–875, https://doi.org/10.1093/jn/nxaa420.

Images via canva.com.

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Kathy Beerman, PhD

Dr. Kathy Beerman teaches in the School of Biological Sciences at Washington State University. The author of several published articles, she is interested in research that focuses on the efficacy of a novel approach to treating iron deficiency anemia in rural regions of Guatemala and Ecuador. Dr. Beerman teaches an undergraduate nutrition course for health majors, as well as a course that prepares students to participate in a 10-day medical mission to Guatemala. Since joining the faculty at Washington State University in 1990, she has been the recipient of several teaching awards (the Burlington Northern Faculty Meritorious Achievement in Teaching Award, the R.M. Wade Foundation Award for Excellence in Teaching, and the Sahlin Faculty Excellence Award for Instruction). More recently, she received the CAS Outstanding Achievement Award in International Activities (2017) and the President’s Award for Leadership (2018). Other scholarly activities include co-author of two introductory nutrition textbooks (Nutritional Sciences: From Fundamentals to Food and NUTR).