Women, considering swimming as a form of exercise to lose weight, have been discouraged from doing so, since researchers suggest that swimming does not burn fat as efficiently as land exercise. The purpose of this study was to compare carbohydrate and fat utilization by women engaging in two different forms of exercise, walking and swimming, at the same intensity and duration. Subjects were 20 moderately trained female subjects, walkers (W) = 10 and swimmers (S) = 10; ages 18-40 years. Measurements of blood free fatty acids (FFA), glycerol, lactate, glucose, free fatty acid turnover (FFAT), respiratory quotient (RQ), and fat oxidation were made during 60 minutes of walking or swimming at the same exercise intensity. Multivariate analysis of variance determined no significant differences between groups in net energy expenditure (NEE), RQ, fat oxidation, blood FFA, glycerol, glucose, and FFAT(p > .05). There was a significant difference between groups in blood lactic acid levels (p < .01). Since it was found that swimming and walking at the same duration and intensity bum similar amounts of fat and carbohydrate as energy sources during exercise, women may find swimming to be a viable form of exercise for weight control.
Loretta DiPietro, Catherine W. Yeckel and James Dziura
Few studies have compared long-term moderate-intensity aerobic versus light-resistance training on serial improvements in glucose tolerance in older people.
Healthy, inactive older (74 ± 5 [SD] years) women (N = 20) were randomized into either a high-volume, moderate-intensity aerobic (ATM, n = 12) or a lower-intensity resistance training (RTL, n = 8) group. Both groups exercised under supervision 4 times per week for 45- to 60-minute sessions over 9 months. Measurements of plasma glucose, insulin, and free fatty acid (FFA) responses to an oral glucose tolerance test (OGTT) were performed at baseline and at 3, 6, and 9 months 48 hours after the last exercise session.
We observed significant improvements in 2-hour glucose concentrations at 3, 6, and 9 months among women in the RTL (152 ± 42 vs 134 ± 33 vs 134 ± 24 vs 130 ± 27 mg · dL−1; P < .05), but not the ATM (151 ± 25 vs 156 ± 37 vs 152 ± 40 vs 155 ± 39 mg · dL−1) group. These improvements were accompanied by an 18% (P < .07) decrease in basal FFA concentrations in the RTL group, whereas basal and 30-minute FFA concentrations increased (P < .05) after training in the ATM group.
These findings suggest that the net physiological benefits of exercise might have been blunted in the ATM group, owing to higher circulating levels of FFA, which might have temporarily interfered with insulin action.
Thiago Correa Porto Gonçalves, Atila Alexandre Trapé, Jhennyfer Aline Lima Rodrigues, Simone Sakagute Tavares and Carlos Roberto Bueno Junior
. , Hennings , S. , Mitchell , J. , Halsall , D. , . . . Wareham , N.J. ( 2001 ). The effect of the Gly16Arg polymorphism of the beta(2)-adrenergic receptor gene on plasma free fatty acid levels is modulated by physical activity . The Journal of Clinical Endocrinology and Metabolism, 86 ( 12
Nicholas W. Baumgartner, Anne M. Walk, Caitlyn G. Edwards, Alicia R. Covello, Morgan R. Chojnacki, Ginger E. Reeser, Andrew M. Taylor, Hannah D. Holscher and Naiman A. Khan
tissues and circulation, has also been observed within the brain, serving as a potential mechanism by which obesity may contribute to cognitive dysfunction. 13 , 14 Excess fat mass can lead to increased levels of circulating free fatty acids, proinflammatory cytokines, chemokines, and immune cells, which
Jakob Tarp, Anna Bugge, Niels Christian Møller, Heidi Klakk, Christina Trifonov Rexen, Anders Grøntved and Niels Wedderkopp
resting metabolic rate and/or increased capacity for glucose and free fatty acid clearance may represent mechanisms explaining beneficial metabolic adaptations with higher muscle fitness. 36 Another potential mechanism, supported by the removal of most of the statistically significant associations when
Miguel A. Sanchez-Lastra, Kyle J. Miller, Rodolfo I. Martínez-Lemos, Antón Giráldez and Carlos Ayán
total cholesterol, 40 triglycerides, 40 and aspartate aminotransferase, 37 as well as improvements in free fatty acids, fasting plasma glucose, and insulin. 34 Moreover, benefits were reported for the percentage of glycosylated hemoglobin A 1c (HbA 1c ), 39 the homeostasis model assessment of