Moderate-intensity exercise enhances overall fitness and muscle adaptations in a person with type 1 diabetes: A case report

Background: Type 1 diabetes mellitus (T1D) is an autoimmune condition characterized by pancreatic β-cell destruction, insulin deficiency, and chronic hyperglycemia, often accompanied by impaired metabolic flexibility, reduced aerobic capacity, and musculoskeletal limitations. While exercise benefits metabolic health in type 2 diabetes and obesity, its specific physiological effects in T1D remain less defined. We report a case of a 22-year-old woman with T1D whose 6-week moderate-intensity exercise enhanced her physical fitness and muscle performance. Methods: A white woman with >10-year T1D completed a 6-week, weekly 45-minute brisk walk at 50–60% heart rate reserve. Key assessments included VO 2 max, 3RM leg press, 30-second sit-to-stand, body composition via DEXA, handgrip strength, and glycemic profiles. Results were conducted pre- and post-intervention, and analyzed using Student’s t-test, reported as mean ± SD. Results: Following structured exercise, the participant’s cardiovascular fitness improved by 14%, lower extremity strength and lower body strength and endurance increased by 12% and 29%. Body composition changes included a 5% reduction in fat mass, a 2% decrease in total mass, and a 2% increase in relative skeletal muscle index, with lean mass and resting metabolic rate unchanged. Glycemic measures remained stable (blood glucose: 123.8 ± 10.2 vs 118.9 ± 22.6 mg/dL, p = 0.641; lactate: 4.0 ± 2.4 vs 5.5 ± 1.5 mmol/L, p = 0.162). Interestingly, handgrip strength declined by 14%. Conclusion: Regular moderate-intensity exercise elicited meaningful gains in lower-body strength, endurance, body composition, cardiovascular fitness, and quality of life in an individual with T1D, without adverse glycemic effects. These results underscore exercise as a safe, effective physiological intervention with translational relevance, highlighting its potential to mitigate T1D-related functional impairments and support long-term metabolic and musculoskeletal health. Supported by the NASA Connecticut Space Grant Consortium Faculty Research Grant, American Physiological Society Local Undergraduate Research Award, College of Arts & Sciences Dean’s Faculty Research Funds and Dean’s Student Research Award, and Greenberg Junior Faculty Research Grant from the University of Hartford. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.