Relationship between Fatigability and Skeletal Muscle Blood Flow in Patients with Type 2 Diabetes

Research Objectives: This study examines the impact of skeletal muscle blood flow on muscle fatigability in individuals with type 2 diabetes. Regular physical activity is essential for managing type 2 diabetes, and there is a connection between physical activity level and fatigability. However, the factors associated with fatigability are unclear. The hypothesis is that skeletal muscle blood flow during exercise plays a significant role in determining fatigability by affecting oxygen utilization in the muscles.

Design: The study was designed as a cross-sectional study.

Setting: The study included type 2 diabetes patients visiting Hamamatsu University Hospital as outpatients between April 2020 and March 2023.

Participants: Participants are selected based on specific criteria, including age between 40 and 65 years, ambulatory independence, and e-GFR >30 ml/min/m2. Exclusion criteria involve severe cardiac, pulmonary, or orthopedic disease, inability to provide consent, and unmeasured skeletal muscle blood flow.

Interventions: Not applicable.

Main Outcome Measures: Fatigability was assessed using an experimental protocol with the BIODEX system3. Maximal muscle strength and angular velocity were measured at baseline. The dynamic fatiguing task involved applying a load of 20% of maximal muscle strength (3 sets of 30 repetitions). Fatigability was calculated as the rate of torque decrease in the third set compared to baseline torque. Skeletal muscle blood flow was measured using near-infrared spectroscopy, with the relative change in total hemoglobin indicating skeletal muscle blood flow.

Results: The final analysis included 44 participants (The median age is 56 years). When adjusting for age, sex, strength-to-weight ratio, and SMI in the analysis of ANCOVA, skeletal muscle blood flow remained independently associated with fatigability (F = 6.203, p = 0.017).

Conclusions: The study suggests that impaired microcirculation and reduced skeletal muscle oxygen utilization efficiency in type 2 diabetes contribute to increased fatigability. The findings highlight the importance of skeletal muscle blood flow during exercise in understanding and addressing fatigability, offering potential directions for future treatment strategies.

Author(s) Disclosures: The authors declare no conflicts of interest.