Work capacity determinants and physiologic cost of weight-supported work in obesity

Dempsey, Jerome A.; Reddan, WG; Balke, Bruno; Rankin, Janet Walberg

doi:10.1152/jappl.1966.21.6.1815

Cited by 115 publications

(71 citation statements)

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“…3,12,32 We also observed that o 2 peak adjusted for LBM was still signifi cantly lower in the obese compared with the nonobese individuals. These observations agree with prior studies, 10,27,32,33 but contrast with the results from others. 8,28,29,31 Our obese had signifi cantly larger LBM than the nonobese, and thus lower o 2 peak (36.6 mL/min/LBM vs 42.4 mL/min/LBM), which closely match the differences reported between obese and normal weight individuals in a study by Ofi r et al 32 Studies with a more limited range in body fat 8,28,29,31 observed similar o 2 peak (mL/min/LBM) values between obese and nonobese, while those studies with larger differences in body fat had similar results to ours.…”

Section: Discussionsupporting

confidence: 90%

“…[25][26][27] However, our results contrast with some who observed o 2 peak (L/min) to be elevated in obesity. 3,4,8,28 o 2 peak is usually increased in obesity, 3,4,8,28 not because of an increased cardiorespiratory capacity or increased fat weight, but rather because of an increase in LBM to support the larger structure.…”

Section: Sex Differencescontrasting

confidence: 99%

“…We observed a decrease in relative o 2 peak (mL/min/kg) in the obese, 25,27,30,31 although this approach is not an adequate representation of CRF in obese subjects. 3,12,32 We also observed that o 2 peak adjusted for LBM was still signifi cantly lower in the obese compared with the nonobese individuals.…”

Section: Discussionmentioning

confidence: 67%

“…8,28,29,31 Our obese had signifi cantly larger LBM than the nonobese, and thus lower o 2 peak (36.6 mL/min/LBM vs 42.4 mL/min/LBM), which closely match the differences reported between obese and normal weight individuals in a study by Ofi r et al 32 Studies with a more limited range in body fat 8,28,29,31 observed similar o 2 peak (mL/min/LBM) values between obese and nonobese, while those studies with larger differences in body fat had similar results to ours. 10,27,32,33 The interrelationships between LBM, height, and o 2 peak are very important, as seen in Figure 6 . When taking out the effect of height on the relationship between LBM with o 2 peak the correlation drops by half (r 5 0.40).…”

Section: Discussionmentioning

confidence: 97%

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Quantification of Cardiorespiratory Fitness in Healthy Nonobese and Obese Men and Women

Lorenzo

Babb

2012

Chest

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Obesity is a widespread and growing problem worldwide and is among the most important health challenges of the 21st century. 1 Exercise is an important component in the prevention and treatment of obesity and, thus, an accurate assessment of the patient's cardiorespiratory fitness (CRF) level to determine optimal workout intensities, exercise modes, and exercise routines is critical. 2 Moreover, a proper quantification and interpretation of CRF is important for assessing who has low CRF, underlying comorbidities, and increased disease risk.Peak oxygen uptake ( o 2 peak ) is routinely measured as a means of evaluating CRF by exercise physiologists, allied health-care providers, epidemiologists, Background: The quantifi cation and interpretation of cardiorespiratory fi tness (CRF) in obesity is important for adequately assessing cardiovascular conditioning , underlying comorbidities, and properly evaluating disease risk. We retrospectively compared peak oxygen uptake ( O 2 peak) (ie, CRF) in absolute terms, and relative terms (% predicted) using three currently suggested prediction equations (Equations R, W, and G). Methods: There were 19 nonobese and 66 obese participants. Subjects underwent hydrostatic weighing and incremental cycling to exhaustion. Subject characteristics were analyzed by independent t test, and % predicted O 2 peak by a two-way analysis of variance (group and equation) with repeated measures on one factor (equation). Results: O 2 peak (L/min) was not different between nonobese and obese adults (2.35 Ϯ 0.80 [SD] vs2.39 Ϯ 0.68 L/min). O 2 peak was higher ( P , .02) relative to body mass and lean body mass in the nonobese (34 Ϯ 8 mL/min/kg vs 22 Ϯ 5 mL/min/kg, 42 Ϯ 9 mL/min/lean body mass vs 37 Ϯ 6 mL/min/lean body mass). Cardiorespiratory fi tness assessed as % predicted was not different in the nonobese and obese (91% Ϯ 17% predicted vs 95% Ϯ 15% predicted) using Equation R, while using Equation W and G, CRF was lower ( P , .05) but within normal limits in the obese (94 Ϯ 15 vs 87 Ϯ 11; 101% Ϯ 17% predicted vs 90% Ϯ 12% predicted, respectively), depending somewhat on sex. Conclusions: Traditional methods of reporting O 2 peak do not allow adequate assessment and quantifi cation of CRF in obese adults. Predicted O 2 peak does allow a normalized evaluation of CRF in the obese, although care must be taken in selecting the most appropriate prediction equation, especially in women. In general, otherwise healthy obese are not grossly deconditioned as is commonly believed, although CRF may be slightly higher in nonobese subjects depending on the uniqueness of the prediction equation. CHEST 2012; 141(4):1031-1039Abbreviations: CRF 5 cardiorespiratory fi tness; LBM 5 lean body mass; MW 5 measured weight; PW 5 predicted weight; o 2 5 oxygen uptake; o 2 peak 5 peak oxygen uptake.

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Section: Discussionsupporting

confidence: 90%

Section: Sex Differencescontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 97%

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Quantification of Cardiorespiratory Fitness in Healthy Nonobese and Obese Men and Women

Lorenzo

Babb

2012

Chest

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“…2,3 During physical activity, these mechanical abnormalities are associated with increased ventilatory requirements secondary to the increased metabolic load. [4][5][6] A greater work of breathing implies greater activation of the respiratory muscles. Some results suggest that respiratory muscle function in obesity may be compromised by the increased load that the muscles are required to overcome, and by some reduction in their capacity.…”

Section: Introductionmentioning

confidence: 99%

Respiratory muscle endurance training in obese patients

Villiot-Danger

Borel

et al. 2010

Int J Obes

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Objective: Increased respiratory muscle work is associated with dyspnea and poor exercise tolerance in obese patients. We evaluated the effect of respiratory muscle endurance training (RMET) on respiratory muscle capacities, symptoms and exercise capacity in obese patients. Design: A total of 20 obese patients hospitalized for 26 ± 6 days to follow a low-calorie diet and a physical activity program were included in this case-control study. Of them, 10 patients performed RMET (30-min isocapnic hyperpnea at 60-80% maximum voluntary ventilation, 3-4 times per week during the whole hospitalization period: RMET group), while the other 10 patients performed no respiratory training (control (CON) group). RMET and CON groups were matched for body mass index (BMI) (45 ± 7 kg m À2 ) and age (42 ± 12 years). Lung function, respiratory muscle strength and endurance, 6-min walking distance, dyspnea (Medical Research Council scale) and quality of life (short-form health survey 36 questionnaire) were assessed before and after intervention. Results: Similar BMI reduction was observed after hospitalization in the RMET and CON groups (À2±1 kg m À2 , Po0.001). No significant change in lung function and respiratory muscle strength was observed except for vital capacity, which increased in the RMET group ( þ 0.20±0.26 l, P ¼ 0.039). Respiratory muscle endurance increased in the RMET group only ( þ 52±27%, Po0.001). Compared with the CON group, the RMET group had greater improvement in 6MWT ( þ 54 ± 35 versus þ 1 ± 7 m, P ¼ 0.007), dyspnea score (À2±1 versus À1±1 points, P ¼ 0.047) and quality of life (total score: þ 251±132 versus þ 84±152 points, P ¼ 0.018) after hospitalization. A significant correlation between the increase in respiratory muscle endurance and improvement in 6MWT distance was observed (r 2 ¼ 0.36, P ¼ 0.005). Conclusions: The present study indicates that RMET is feasible in obese patients and can induce significant improvement in dyspnea and exercise capacity. RMET may be a promising tool to improve functional capacity and adherence to physical activities in this population, but further studies are needed to confirm these results.

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Relief of Cardiorespiratory Symptoms and Increased Physical Activity After Surgically Induced Weight Loss

Karason¹,

Lindroos²,

Stenlöf³

et al. 2000

Arch Intern Med

156

119

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Work capacity determinants and physiologic cost of weight-supported work in obesity

Cited by 115 publications

References 0 publications

Quantification of Cardiorespiratory Fitness in Healthy Nonobese and Obese Men and Women

Quantification of Cardiorespiratory Fitness in Healthy Nonobese and Obese Men and Women

Respiratory muscle endurance training in obese patients

Relief of Cardiorespiratory Symptoms and Increased Physical Activity After Surgically Induced Weight Loss

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