The Role of Exercise in the Treatment of Obesity
ABSTRACT The United States is in the midst of a significant public health problem that relates to obesity and inactivity. This epidemic has far-ranging consequences for our workforce and our children and shows no signs of slowing in the near future. Significant research has been performed on the effects of exercise for the reduction of body weight; results of most studies indicate that exercise alone has a small effect on body-weight reduction independent of caloric restriction. However, when combined with dietary restriction, exercise has a synergistic effect and enhances weight loss beyond the effect of diet alone. In addition, exercise has been shown to have significant beneficial effects on cardiovascular and metabolic risk factors independent of actual weight loss, and losing just a small amount of weight can have a significant beneficial effect on these parameters. Genetic factors related to obesity have been found to be positively modified when persons incorporate physical activity into their lifestyle. Sitting time appears to be an independent risk factor for the development of metabolic risk factors; persons who spend more time sitting and watching television have worse metabolic profiles, even if they achieve the recommended amount of physical activity per week, than do those who move about throughout the day. Exercise also is essential for the prevention of weight gain over a life span, although the amount required to prevent weight gain may be closer to twice the amount of exercise recommended by the current Physical Activity Guidelines for Americans (www.health.gov/paguidelines). In many ways, the physiatrist is the most well prepared of all the specialists to address the complex, multidimensional problems of obesity and inactivity.
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ABSTRACT: Obesity contributes to stress induced impairments in endothelium-dependent vasodilation (EDV), a precursor to atherosclerosis. Since obesity is associated with inflammation and oxidative stress, we sought to determine if a single bout of strenuous weight lifting (SWL) reduces EDV among sedentary obese adults. Participants included 9 obese (OB) (BMI 30.0-40.0 kg/m(2)) and 8 lean (LN) (BMI 18.5-24.9 kg/m(2)) sedentary young women. All participants underwent a single bout of SWL using a progressive leg-press protocol. Brachial artery flow-mediated dilation (FMD) (an index of EDV) was determined using ultrasonography before and after SWL. Sublingual nitroglycerin (NTG) was used to determine brachial artery endothelium-independent vasodilation following SWL. Brachial artery FMD was significantly reduced in OB and LN women (LN: 6.4 ± 1.6%, p = 0.22) after SWL. There was no difference in the magnitude of change pre- and post-SWL between groups (OB: -2.4 ± 0.6% and LN: -2.2 ± 1.6%, p = 0.84). Dilation to NTG was lower in OB (21.6 ± 1.3%) compared to LN women (27.6 ± 2.1%, p = 0.02) and associated with body weight (r = -0.70, p = 0.01). These data suggest that EDV is reduced in woman after acute resistance exercise. Dilations to NTG were lower in obese compared to lean woman and associated with body weight suggesting that changes in sensitivity of blood vessels to NO occurs during obesity. These findings may be important for understanding vascular risk following acute exercise in obesity.Frontiers in Physiology 07/2014; 5:253. DOI:10.3389/fphys.2014.00253
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ABSTRACT: The study investigated the effectiveness of home-based exercise combined with a slight caloric restriction on weight change during 12 months in non-obese women. A randomized clinical trial with a factorial design was conducted from 2003 to 2005. Two hundred three middle-aged women (Rio de Janeiro/Brazil), 25-45 years, were randomly assigned to one of two groups: control (CG) and home-based exercise (HB). The HB group received a booklet on aerobic exercise that could be practiced at home (3 times/week-40 min/session), in low-moderate intensity, during 12 months. Both groups received dietary counseling aimed at a slight energy restriction of 100-300 calories per day. The HB experienced a greater weight loss in the first 6 months (-1.4 vs. -0.8 kg; p=0.04), but after 12 months there was no differences between groups (-1.1 vs. -1.0; p=0.20). Of the serum biochemical markers, HDL cholesterol showed major change, with an increase at month 12 of 18.3mg/dl in the HB compared to 9.5 in the CG (p<0.01). Home-based exercise promoted greater weight reduction during the first 6 months after which no further benefits are observed. Continuous favorable changes in HDL cholesterol after 1 year suggest that home-based exercise promote health benefits.Preventive Medicine 09/2010; 51(3-4):247-52. DOI:10.1016/j.ypmed.2010.07.012 · 2.93 Impact Factor
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ABSTRACT: World-wide obesity has risen to alarming levels. We present experimental support for a new and very challenging hypothesis linking obesity, voracity, and growth hormone (GH) deficiency, to the consumption of elevated amounts of the amino-acid glutamate (GLU). Supraphysiological doses of GLU are toxic for neuronal cells. Human data were obtained from 807,592 German conscripts born between 1974 and 1978, and from 1,432,368 women of the German birth statistics (deutsche Perinatalerhebung) 1995-1997. The effects of orally administered monosodium glutamate (MSG) were investigated in 30 pregnant Wistar rats and their offspring. Pregnant animals either received no extra MSG, or 2.5 g MSG, or 5 g MSG per day, up to the end of the weaning period. In all, 2.5 g, respectively 5 g, MSG accounted for some 10%, respectively 20%, of dry weight of the average daily food ration. After weaning, MSG feeding was continued in the offspring. Morbid obesity associates with short stature. Average stature of conscripts progressively declines when body mass index increases above 38 kg/m2. Also morbidly obese young women are shorter than average though to a lesser extent than conscripts. Oral administration of MSG to pregnant rats affects birth weight of the offspring. Maternal feeding with 5 g MSG per day results in severe birth weight reduction (P<0.01). Weight increments remain subnormal when MSG feeding to the mothers is maintained during weaning (P < 0.01). GH serum levels are affected in animals that received MSG during prenatal life via maternal feeding. Animals that are kept on high MSG diet (5 g MSG per day) continue to show serum GH levels that are as low or even lower than those of MSG injected animals (P < 0.05), both at day 30 and at day 90 of life. Animals that were kept on medium MSG diet (2.5 g MSG per day) showed low serum GH levels at day 30 of life (P < 0.01), but seemed to partially recover before day 90. Almost identical results were observed in IGF-1 serum levels. Oral MSG resulted in dose dependent voracity. The animals fed 5 g MSG per day increased water uptake by threefold (P < 0.01), and food uptake by almost two-fold (P < 0.01). The influence of MSG is in general more marked in males than in females. Interpretation: GLU is a widely used nutritional substance that potentially exhibits significant neuronal toxicity. Voracity, and impaired GH secretion are the two major characteristics of parenterally administered GLU-induced neuronal damage. GLU maintains its toxicity in animals even when administered orally. Males appear to be more sensitive than females. The present study for the first time demonstrates, that a widely used nutritional monosubstance--the flavouring agent MSG--at concentrations that only slightly surpass those found in everyday human food, exhibits significant potential for damaging the hypothalamic regulation of appetite, and thereby determines the propensity of world-wide obesity. We suggest to reconsider the recommended daily allowances of amino acids and nutritional protein, and to abstain from the popular protein-rich diets, and particularly from adding the flavouring agents MSG.European Journal of Clinical Nutrition 01/2006; 60(1):25-31. DOI:10.1038/sj.ejcn.1602263 · 2.95 Impact Factor