| 1. |
- Ekman, Carl, et al.
(författare)
-
Less pronounced response to exercise in healthy relatives to type 2 diabetic subjects compared with controls
- 2015
-
Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 119:9, s. 953-960
-
Tidskriftsartikel (refereegranskat)abstract
- Healthy first-degree relatives with heredity of type 2 diabetes (FH+) are known to have metabolic inflexibility compared with subjects without heredity for diabetes (FH-). In this study, we aimed to test the hypothesis that FH+ individuals have an impaired response to exercise compared with FH-. Sixteen FH+ and 19 FH- insulin-sensitive men similar in age, peak oxygen consumption ((V) over dot(O2 peak)), and body mass index completed an exercise intervention with heart rate monitored during exercise for 7 mo. Before and after the exercise intervention, the participants underwent a physical examination and tests for glucose tolerance and exercise capacity, and muscle biopsies were taken for expression analysis. The participants attended, on average, 39 training sessions during the intervention and spent 18.8 MJ on exercise. (V) over dot(O2 peak)/kg increased by 14%, and the participants lost 1.2 kg of weight and 3 cm waist circumference. Given that the FH- group expended 61% more energy during the intervention, we used regression analysis to analyze the response in the FH+ and FH- groups separately. Exercise volume had a significant effect on (V) over dot(O2 peak), weight, and waist circumference in the FH- group, but not in the FH+ group. After exercise, expression of genes involved in metabolism, oxidative phosphorylation, and cellular respiration increased more in the FH- compared with the FH+ group. This suggests that healthy, insulin-sensitive FH+ and FH- participants with similar age, (V) over dot(O2 peak), and body mass index may respond differently to an exercise intervention. The FH+ background might limit muscle adaptation to exercise, which may contribute to the increased susceptibility to type 2 diabetes in FH+ individuals.
|
|
| 2. |
- Elgzyri, Targ, et al.
(författare)
-
First-degree relatives of type 2 diabetic patients have reduced expression of genes involved in fatty acid metabolism in skeletal muscle
- 2012
-
Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 97:7, s. E1332-E1337
-
Tidskriftsartikel (refereegranskat)abstract
- Context: First-degree relatives of patients with type 2 diabetes (FH+) have been shown to have decreased energy expenditure and decreased expression of mitochondrial genes in skeletal muscle. In previous studies, it has been difficult to distinguish whether mitochondrial dysfunction and differential regulation of genes are primary (genetic) or due to reduced physical activity, obesity, or other correlated factors.Objective: The aim of this study was to investigate whether mitochondrial dysfunction is a primary defect or results from an altered metabolic state.Design: We compared gene expression in skeletal muscle from 24 male subjects with FH and 26 without FH matched for age, glucose tolerance, VO2peak (peak oxygen uptake), and body mass index using microarrays. Additionally, type fiber composition, mitochondrial DNA content, and citrate synthase activity were measured. The results were followed up in an additional cohort with measurements of in vivo metabolism. Results: FH+ vs. FH- subjects showed reduced expression of mitochondrial genes (P = 2.75 x 10(-6)), particularly genes involved in fatty acid metabolism (P = 4.08 x 10(-7)), despite similar mitochondrial DNA content. Strikingly, a 70% reduced expression of the monoamine oxidase A(MAOA) gene was found in FH+ vs. FH- individuals (P = 0.0009). Down-regulation of the genes involved in fat metabolism was associated with decreased in vivo fat oxidation and increased glucose oxidation examined in an additional cohort of elderly men.Conclusions: These results suggest that genetically altered fatty acid metabolism predisposes to type 2 diabetes and propose a role for catecholamine-metabolizing enzymes like MAOA in the regulation of energy metabolism. (J Clin Endocrinol Metab 97: E1332-E1337, 2012)
|
|
| 3. |
- Glans, Forouzan, et al.
(författare)
-
Evaluation of the effects of exercise on insulin sensitivity in Arabian and Swedish women with type 2 diabetes.
- 2009
-
Ingår i: Diabetes Research and Clinical Practice. - : Elsevier BV. - 1872-8227 .- 0168-8227. ; 85, s. 69-74
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: The purpose of this study was to evaluate the effects of exercise on cardio-respiratory fitness and insulin sensitivity in sedentary, overweight Arabian and Swedish women with type 2 diabetes. METHODS: Eighteen Arabian and 14 Swedish women participated in a supervised 6-month resistance training and aerobic program of moderate intensity. Insulin sensitivity and VO(2max) were measured at entry to the study and after 3 and 6 months training. RESULTS: After 6 months exercise, insulin sensitivity (M-value) increased (2.7+/-1.4mgkg(-1)min(-1) vs. 3.4+/-2mgkg(-1)min(-1), p<0.05) in all patients and accounted for by an increase in non-oxidative glucose metabolism (0.3+/-1.1mgkg(-1)min(-1) vs. 1.5+/-1.5mgkg(-1)min(-1), p<0.005) with no significant difference between the ethnic groups. Notably, significant improvement in HbA1c was only seen in the Swedish patients who achieved greater exercise intensity (73.3+/-4.8% vs. 63.3+/-5.2% of maximum heart rate, p<0.005). No changes were observed regarding VO(2max) or lipid profile in either group. CONCLUSIONS: Although a 6-month exercise intervention of moderate intensity in Arabian and Swedish patients with type 2 diabetes can improve insulin sensitivity it is hampered by the metabolic inflexibility of switching between oxidation of glucose or fat.
|
|
| 4. |
- Tornberg, Åsa, et al.
(författare)
-
Assessment of exercise capacity in women with type 2 diabetes.
- 2008
-
Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 28, s. 294-298
-
Tidskriftsartikel (refereegranskat)abstract
- The primary aim of this study was to compare the maximal oxygen uptake as evaluated from a submaximal exercise test (EVO(2peak)) to direct measurements of VO(2peak) during a maximal exercise test as means of monitoring the aerobic endurance capacity in women with type 2 diabetes (T2D). Twenty-seven women with T2D participated in the study. The program consisted of combined group training 1 h twice a week during 12 weeks and walks 1 h per week. EVO(2 max) was estimated using a submaximal exercise test on a bicycle ergometer ad modumAstrand. VO(2peak) and maximal work rate were measured using an incremental maximal exercise test on an electrically braked bicycle ergometer at baseline and after 6 and 12 weeks. EVO(2peak)was higher than VO(2peak)at baseline and significantly higher at 12 weeks (EVO(2peak)1.92 +/- 0.54 l min(-1), VO(2peak) 1.41 +/- 0.36, P < 0.005). Maximal work rate increased significantly after 12 weeks (12 +/- 15, P < 0.005) compared to baseline. The main finding of this study was that EVO(2peak) assessed using a submaximal exercise test, systematically overestimated VO(2peak). The combined group training increased maximal work rate but not VO(2peak). This is likely to reflect peripheral adaptation to exercise and/or improved mechanical efficiency.
|
|
| 5. |
- Tornberg, Åsa, et al.
(författare)
-
Exercise capacity in relation to body fat distribution and muscle fibre distribution in elderly male subjects with impaired glucose tolerance, type 2 diabetes and matched controls.
- 2011
-
Ingår i: Diabetes Research and Clinical Practice. - : Elsevier BV. - 1872-8227 .- 0168-8227. ; 94, s. 57-63
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim of this study was to examine the impact of insulin sensitivity and muscle fibre composition to exercise capacity in individuals with type 2 diabetes (T2D), impaired glucose tolerance (IGT) and normal glucose tolerance (NGT). METHODS: Thirty-nine male patients with T2D, 44 male subjects with IGT and 58 subjects with NGT matched for age, weight and body mass index (BMI) participated in the study. Insulin sensitivity was obtained with hyperinsulinemic-euglycemic clamps, muscle fibre distribution with a biopsy and exercise capacity from an incremental exercise test. Anthropometric measurements as height, weight, waist and hip circumference were performed. RESULTS: There were small differences between groups in waist hip ratio (WHR) with significance attained between NGT and T2D. There was a progressive reduction in exercise capacity, both expressed as VO(2peak) and work rate from subjects with NGT to IGT to T2D. Multiple regression analysis with VO(2peak) as dependent variable showed insulin sensitivity to be the most important factor followed by Type I fibres. WHR and capillary density also influenced the variance of VO(2peak). CONCLUSION: Exercise capacity is independently related to insulin sensitivity, muscle fibre composition and WHR in subjects with NGT, IGT and T2D who are matched for age and BMI.
|
|
| 6. |
- Tornberg, Åsa, et al.
(författare)
-
Impact of exercise intensity and duration on insulin sensitivity in women with T2D.
- 2010
-
Ingår i: European Journal of Internal Medicine. - : Elsevier BV. - 1879-0828 .- 0953-6205. ; 21:5, s. 404-408
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Clinical guidelines seldom provide in depth information about the most suitable type and intensity of exercise to obtain optimal benefit in different subgroups of T2D individuals. The aim of this study was to examine the effect of group exercise training on exercise capacity, insulin sensitivity and HbA1c in women with diabetes. METHODS: Twenty-two women with T2D participated in a supervised group exercise program for six months. The program combined endurance and resistance exercise. The duration and intensity of exercise for each subject was recorded. The volume of exercise was calculated as the product of exercise duration and intensity. Exercise capacity, insulin sensitivity and HbA1c were measured at baseline and after six months of training. The subjects were dichotomized with respect to training volume in a high training volume group and a low training volume group. RESULTS: Exercise capacity did not change significantly during the training period. Insulin sensitivity increased significantly and HbA1c decreased significantly from baseline in the high volume group but not in the low volume group. The increase in insulin sensitivity was explained with the intensity of exercise by 30%. The reduction in HbA1c was explained with exercise by 25%. CONCLUSION: Improvement in insulin sensitivity after six months combined supervised group training in female diabetic subjects is related to exercise intensity, whereas the reduction in HbA1c is related mainly to training volume. Metabolic effects of training may be seen in the absence of improved exercise capacity.
|
|
| 7. |
- Tornberg, Åsa, et al.
(författare)
-
Relation between cycling exercise capacity, fiber-type composition, and lower extremity muscle strength and muscle endurance.
- 2011
-
Ingår i: Journal of Strength and Conditioning Research. - 1533-4287. ; 25:1, s. 16-22
-
Tidskriftsartikel (refereegranskat)abstract
- Segerström, ÅB, Holmbäck, AM, Hansson, O, Elgzyri, T, Eriksson, K-F, Ringsberg, K, Groop, L, Wollmer, P, and Thorsson, O. Relation between cycling exercise capacity, fiber-type composition, and lower extremity muscle strength and muscle endurance. J Strength Cond Res 25(1): 16-22, 2011-The aim of the study was to determine the relation between peak oxygen uptake (&OV0312;o2peak), peak work rate (WRpeak), fiber-type composition, and lower extremity strength and endurance during a maximal incremental cycle test. Thirty-nine healthy sedentary men, aged 30-46, participated in the study. Subjects performed a maximal incremental cycle test and isokinetic knee extension (KE) and flexion (KF) strength and endurance tests at velocities of 60 and 180°·s. Muscle biopsies were taken from m. vastus lateralis and analyzed for fiber-type composition. A significant correlation existed between KE strength and &OV0312;o2peak and WRpeak. Also, KF endurance correlated significantly to &OV0312;o2peak and WRpeak. The KE endurance correlated significantly to WRpeak (rp = 0.32, p < 0.05) and almost significantly to &OV0312;o2peak (rp = 0.28, p = 0.06). Stepwise multiple regression analyses showed that KE strength, KF endurance, and the percentage of type I fibers could explain up to 40% of the variation in &OV0312;o2peak and WRpeak. The performance of sedentary subjects in a maximal incremental cycle test is highly affected by knee muscle strength and endurance. Fiber-type composition also contributes but to a smaller extent.
|
|
| 8. |
- Tornberg, Åsa, et al.
(författare)
-
Upper Body Muscle Strength and Endurance in Relation to Peak Exercise Capacity During Cycling in Healthy Sedentary Male Subjects.
- 2011
-
Ingår i: Journal of Strength and Conditioning Research. - 1533-4287. ; 25, s. 1413-1417
-
Tidskriftsartikel (refereegranskat)abstract
- Segerström, AB, Holmbäck, AM, Elzyri, T, Eriksson, KF, Ringsberg, K, Groop, L, Thorsson, O, and Wollmer, P. Upper body muscle strength and endurance in relation to peak exercise capacity during cycling in healthy sedentary male subjects. J Strength Cond Res 24(x): 000-000, 2010-The aim of this study was to investigate the relation between upper body muscle strength and endurance, and exercise capacity during an incremental cycle exercise test in sedentary healthy male subjects before and after 6 months of combined supervised group training. Exercise capacity was measured as maximal oxygen consumption (&OV0312;O2peak) and maximum work rate (WRpeak). Muscle strength and endurance of the upper body were assessed by bench press and isometric measurement of trunk extensor and flexor maximum voluntary contraction (MVC) and trunk extensor and flexor endurance. Thirty-one subjects were studied before and after the training period. Bench press and trunk extensor MVC correlated to exercise capacity at baseline and after training. Training improved &OV0312;O2peak and WRpeak. The correlation between trunk extensor MVC and exercise capacity improved after training. Upper body strength may affect exercise capacity by increasing the rider's ability to generate force on the handlebar that can be transmitted to the pedals. Resistance training of the arms, chest, and trunk may help improve cycling performance.
|
|
