Exercise provides many metabolic benefits for people with type 2 diabetes; nevertheless, the ability to switch substrate oxidation from fat to carbohydrate and back, known as metabolic flexibility (MetFlex), in response to prolonged exercise training has not been thoroughly explored.

Purpose: The goal of this analyses was to investigate changes in MetFlex after an exercise intervention. We enrolled healthy sedentary participants with obesity (HSO) and participants with type 2 diabetes (T2DM) in a 10-week aerobic exercise intervention.

Methods: Seventeen participants with T2DM (8 females; 52.9 years; BMI= 36.9 kg/m2 and 9 males; 48.8 years; BMI= 33.3 kg/m2) and seven HSO (5 females; 44.8 years, BMI= 37.6 kg/m2 and 2 males; 46.5 years, BMI= 36.2 kg/m2) completed the intervention. MetFlex was assessed as the respiratory quotient (RQ) kinetic response after ingesting a standard high CHO breakfast during a 24-h energy expenditure measurement in a whole-room respiratory chamber. Briefly, the kinetics between the lowest RQ and highest RQ points were analyzed by a simple linear regression between time (1-minute resolution) and RQ units (RQUnits). Individual data were time-aligned and averaged for each group and moments (PRE and POST intervention), then slopes and intercepts for T2DM vs. HSO groups and PRE vs. POST were compared using a multiple regression model.

Results: At PRE-intervention, HSO group had a significantly lower intercept than T2DM (HSO=0.737 vs. T2DM=0.705; P<0.001) and slower RQ kinetics as demonstrated by a greater slope (HSO=0.00448 RQUnits/min vs. T2DM=0.00332 RQUnits/min; F=18.1, P=0.001). After the exercise intervention only T2DM significantly increased their slope (POST= 0.003944 RQUnits/min; F=6.47, P=0.013).

Conclusions: Our results indicate that participants with diabetes significantly improve MetFlex following a prolonged aerobic exercise intervention.

Disclosure

E.A. Carnero: None. C.P. Bock: None. N. Stephens: None. R.E. Pratley: Other Relationship; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eisai Inc., GlaxoSmithKline plc., Janssen Pharmaceuticals, Inc., Lexicon Pharmaceuticals, Inc., Ligand Pharmaceuticals, Inc., Eli Lilly and Company, Merck & Co., Inc., Novo Nordisk Inc., Pfizer Inc., Sanofi-Aventis, Takeda Development Center Americas, Inc.. S.R. Smith: None. L.M. Sparks: None.

© 2018 by the American Diabetes Association.
2018
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.