Differences of Blood Flow Responses in Two Hand Exercise Types between Healthy Adults and Individuals with Diabetes Mellitus

Research Objectives: To evaluate the changes in blood flow responses before and after isometric and dynamic handgrip exercises between healthy adults and individuals with diabetes mellitus (DM).

Design: Cross-sectional design with before-after trial test.

Setting: University research lab with trained medical staff and researchers with the temperature control at 21 C° (70 F°).

Participants: The study included two groups of participants: 22 healthy adults (HA) and three adults with type 2 DM. The participants were recruited through flyers and among students in school, using volunteer and convenience sampling methods. The age range of participants was between 18 to 80.

Interventions: The isometric exercise involved gripping the dynamometer at 30% of MVC and holding it for 90 seconds. The dynamic exercise involved gripping the dynamometer at 30% of MVC for 3 minutes, with one grip per second (total of 180 grips). The subjects were asked to rest for 10 minutes between each trial.

Main Outcome Measures: Blood flow was measured 5 minutes before and after each exercise using the Laser Doppler Flowmeter (LDF) with two channels, one on the thenar muscle and the other on the forearm (on the flexor digitorum superficialis, FDS). The baseline average was used to normalize all the post-evaluation of LDF (non-unit ratio).

Results: The study showed that blood flow in HA increased to 1.37 and 1.20 times compared to baseline after isometric and 1.31 and 1.25 after dynamic handgrip exercises on the channel of the thenar muscle and the FDS, respectively. In contrast, the blood flow in individuals with type 2 DM decreased to 0.76 after the isometric exercise on both channels. However, blood flow in DM increased to 1.25 and 1.21 after the dynamic exercise on both channels.

Conclusions: For clinical practice, dynamic exercise to improve peripheral circulation might be a better choice. Further research is needed to determine the optimal types and intensity of exercise due to the small sample size in this study.

Author(s) Disclosures: The authors of this absrtact do no have any conflict of interests to declare.