Regional muscle glucose uptake remains elevated one week after cessation of resistance training independent of altered insulin sensitivity response in older adults with Type 2 diabetes
ABSTRACT Background: Aging is associated with a decline in skeletal muscle size. Muscle is critical both for mobility and glucose disposal. While resistance exercise (RE) increases muscle mass and function in the elderly, its role in improving glucose utilization is less clear. Aims: To investigate whether muscle size was linked with insulin sensitivity (IS) in elders with diabetes following RE and if regional muscle glucose uptake differed from systemic glucose utilization. Method: Seven (68.4±5.9 yrs) adults with diabetes participated. After 16 weeks of RE, within 24 hours (post 1) and after 1 week of no exercise (post 2), lean tissue cross-sectional area (CSA) and IS via glucose infusion rate (GIR) were assessed along with a standardized FDG-PET uptake value (SUV). Results: CSA increased between pretest (108.5±35.3 cm2) and post 1 (116.8±40.9 cm2), p=0.02 and did not differ at post 2 (116.0±39.3 cm2). GIR during the 40 mU/m2/min insulin clamp differed between pretest (22.0±15.8 mg/kg/min) and post 1 (67.9±72.8 mg/kg/min), and post 1 and post 2 (25.0±27.2 mg/kg/min), but not between pretest and post 2. GIR results during the 200 mU/ m2/min insulin clamps also differed between pretest and post 1, and post 1 and post 2 but not between pretest and post 2. FDG-SUV increased between pretest (1.1±0.2) and post 1 (1.4±0.3), and remained stable between post 1 and post 2 (1.4±0.4). Conclusion: RE that increased muscle size and FDG-SUV improved IS 24 hours but not 1 week after exercise training.
SourceAvailable from: Claudio Melibeu Bentes[Show abstract] [Hide abstract]
ABSTRACT: Six men and six women (24.4 ± 6.4 years) who had been diagnosed with T1D for 7.3 ± 6.8 years volunteered for the study. Three RT sessions were repeated with the same experimental approach with randomized load percentages. Blood glucose measurements were performed at rest, after warm-up, immediately after the last set of each exercise, and 10, 20, and 30 minutes after the exercise session. Significant decreases from rest for blood glucose concentration in each intensity vs. post warm-up, immediately post exercise session, and 10, 20 and 30 minutes after total training session were observed. Effect size (ES) results for the 60 and 80% of 1RM intensities demonstrated large magnitudes. The three intensities investigated promoted a reduction in blood glucose levels and therefore can be recommended for diabetic patients. In addition, the moderate and high intensities appear to lower blood glucose levels to a greater extent than the low intensity.Research in Sports Medicine An International Journal 01/2014; 22(1):75-87. DOI:10.1080/15438627.2013.852096 · 1.43 Impact Factor
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ABSTRACT: Muscle's structural composition is an important factor underlying muscle strength and physical function in older adults. There is an increasing amount of research to support the clear disassociation between the loss of muscle lean tissue mass and strength with aging. This disassociation implies that factors in addition to lean muscle mass are responsible for the decreases in strength and function seen with aging. Intermuscular adipose tissue (IMAT) is a significant predictor of both muscle function and mobility function in older adults and across a wide variety of comorbid conditions such as stroke, spinal cord injury, diabetes, and COPD. IMAT is also implicated in metabolic dysfunction such as insulin resistance. The purpose of this narrative review is to provide a review of the implications of increased IMAT levels in metabolic, muscle, and mobility function. Potential treatment options to mitigate increasing levels of IMAT will also be discussed.International Journal of Endocrinology 01/2014; 2014:309570. DOI:10.1155/2014/309570 · 1.52 Impact FactorThis article is viewable in ResearchGate's enriched formatRG Format enables you to read in context with side-by-side figures, citations, and feedback from experts in your field.
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ABSTRACT: Objectives: Intramuscular adipose tissue (IMAT) is recognized as a negative predictor of both muscle and mobility function in older adults, however the mechanism by which IMAT may negatively influence muscle and mobility function is currently unknown. The release of pro-inflammatory cytokines from IMAT provides a potential reason for these negative associations. To explore this hypothesis we compared IMAT and muscular inflammation in age-and BMI-matched older non-obese frail and non-frail adults. We also sought to examine the relationship between IMAT and inflammation, and muscle and mobility function in this group of older adults. Design: A case-control sampling was used for this study. Age-and BMI-matched non-obese frail and non-frail individuals (<65 years) were recruited. Measurements: MRI was used to quantify thigh IMAT and lean tissue. Unilateral muscle biopsies were used to quantify muscular inflammation as represented by interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-α). Muscle and mobility function was also measured using a maximal voluntary isometric contraction, six-minute walk, and self-selected gait speed. Participants: 26 older (80.7 +/- 5.4 years) individuals (8 frail and 18 non-frail) were enrolled. Results: The frail-group had increased IMAT (p<0.01) and decreased lean tissue (p<0.01), and elevated IL-6 muscle mRNA (p=0.02) and IL-6 protein content (p=0.02) compared to the non-frail group. IMAT was significantly associated with IL-6 mRNA (r=0.43, p=.04) and protein expression within the muscle (r=0.41, p= 0.045). IL-6 mRNA was significantly associated with six-minute walk (r=-0.63, p<0.01), and gait speed (r=-0.60, p <0.01) and IL-6 protein was significantly associated with muscle force (r=-0.54, p=0.01), six-minute walk (r=-0.66, p<0.01), and gait speed (r=-0.76, p<0.01). No significant relationships were found for any variables with TNF-a. Conclusion: Non-obese, older, frail individuals have increased IMAT and muscular inflammation when compared to their non-frail, age- and BMI-matched peers. A significant relationship exists between IMAT and muscle IL-6 expression as well as between IL-6 and muscle and mobility function of these older adults. This IMAT-inflammatory pathway provides a potential link between IMATs and decreased muscle and mobility function.The Journal of Nutrition Health and Aging 05/2014; 18(5):532-538. DOI:10.1007/s12603-014-0019-1 · 2.39 Impact Factor