Effects of Nordic walking on cardiovascular risk factors in overweight individuals with type 2 diabetes, impaired or normal glucose tolerance.

BACKGROUND: Physical activity remains a valuable prevention for metabolic disease. The effects of Nordic walking on cardiovascular risk factors were determined in overweight individuals with normal or disturbed glucose regulation. METHODS: We included 213 individuals, aged 60 ± 5.3 years and with body mass index (BMI) of 30.2 ± 3.8 kg/m(2); of these, 128 had normal glucose tolerance (NGT), 35 had impaired glucose tolerance (IGT) and 50 had type 2 diabetes mellitus (T2DM). Participants were randomized to unaltered physical activity or to 5 h per week of Nordic walking with poles, for a 4-month period. Dietary habits were unaltered. BMI, waist circumference, blood pressure, glucose tolerance, clinical chemistry, maximal oxygen uptake (peak VO(2)) and self-reported physical activity (questionnaire) were assessed at the time of inclusion and after 4 months. The participants in the exercise-intervention group kept a walking diary. RESULTS: In the NGT exercise group, self-reported physical activity increased markedly, and body weight (-2.0 ± 3.8 kg), BMI (-0.8 ± 1.4 kg/m(2)) and waist circumference (-4.9 ± 4.4 cm) (mean ± SD) decreased. Exercise power output (12.9 ± 9.9 W) and peak VO(2) (2.7 ± 2.8 mL/kg/min) increased in the IGT exercise group. More cardiovascular risk factors were improved after exercise intervention in people with NGT compared with those with IGT or T2DM. Exercise capacity improved significantly in all three groups of participants who reported at least 80% compliance with the scheduled exercise. CONCLUSIONS: Nordic walking improved anthropometric measurements and exercise capacity. However, unsupervised Nordic walking may not provide a sufficient increase in exercise intensity to achieve ultimate health-promoting benefits on the cardiovascular parameters assessed in this study, particularly for those with disturbed glucose regulation.

Evidence against a sexual dimorphism in glucose and fatty acid metabolism in skeletal muscle cultures from age-matched men and post-menopausal women.

AIM: In vivo whole body differences in glucose/lipid metabolism exist between men and women. Thus, we tested the hypothesis that intrinsic sex differences exist in skeletal muscle gene expression and glucose/lipid metabolism using cultured myotubes. METHODS: Myotube cultures were prepared for gene expression and metabolic studies from vastus lateralis skeletal muscle biopsies obtained from age-matched men (n = 11; 59 +/- 2 years) and post-menopausal women (n = 10; 60 +/- 1 years). RESULTS: mRNA expression of several genes involved in glucose and lipid metabolism was higher in skeletal muscle biopsies from female vs. male donors, but unaltered between the sexes in cultured myotubes. Basal and insulin-stimulated glucose uptake, as well as glucose incorporation into glycogen, was similar in myotube cultures derived from male vs. female donors. In males vs. females, insulin increased glucose uptake (1.3 +/- 0.1 vs. 1.5 +/- 0.1-fold respectively) and incorporation into glycogen (2.3 +/- 0.3 vs. 2.0 +/- 0.3-fold respectively) to the same extent. Basal fatty acid oxidation and rate of uptake/accumulation was similar between sexes. In response to the 5'AMP-activated protein kinase activator AICAR, lipid oxidation was increased to the same extent in myotubes established from male vs. female donors (1.6 +/- 0.6 vs. 2.0 +/- 0.3-fold respectively). Moreover, the AICAR-induced rate of uptake/accumulation was similar between sexes. CONCLUSION: Differences in metabolic parameters and gene expression profiles between age-matched men and post-menopausal women noted in vivo are not observed in cultured human skeletal muscle cells. Thus, the sexual dimorphism in glucose and lipid metabolism is likely a consequence of systemic whole body factors, rather than intrinsic differences in the skeletal muscle proper.