The Ventilatory Response to Exercise Does Not Differ Between Obese Women With and Without Dyspnea on Exertion

Wood, Helen E.; Semon, Trisha L.; Comeau, Laurie A.; Schwartz, Belinda; MacDougall, Rebecca M.; Klocko, M N; Babb, Tony G.

doi:10.1007/978-0-387-73693-8_90

Cited by 10 publications

(7 citation statements)

References 12 publications

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“…In agreement with our previous studies (Babb et al, 2002; Babb et al, 2008a; Lorenzo and Babb, 2011; Wood et al, 2008) and work by Dempsey (Dempsey et al, 1966), the subjects in the present study had normal ventilatory responses to exercise. There were no differences in the exercise responses between the obese women +DOE and −DOE that would explain why some women experienced much stronger breathlessness, implying that submaximal or maximal exercise variables also do not contribute significantly to breathlessness during exercise.…”

Section: Discussionsupporting

confidence: 93%

Weight loss reduces dyspnea on exertion in obese women

Bernhardt

Babb

2014

Respiratory Physiology & Neurobiology

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During submaximal exercise, some otherwise healthy obese women experience breathlessness, or dyspnea on exertion (+DOE), while others have mild or no DOE (−DOE). We investigated whether weight loss could reduce DOE. 29 obese women were grouped based on their Ratings of Perceived Breathlessness (RPB) during constant load 60W cycling: +DOE (n=14, RPB≥4, 34±8yr, 36±3kg/m2) and −DOE (n=15, RPB≤2, 32±8yr, 36±4kg/m2) and then completed a 12-week weight loss program. Both groups lost a moderate amount of weight (+DOE: 6.6±2.4kg, −DOE: 8.4±3.5kg, p<0.001). RPB decreased significantly in the +DOE group (from 4.7±1.1 to 3.1±1.6) and remained low in the −DOE (from 1.5±0.7 to 1.6±1.1) (interaction p<0.002). Most physiological variables measured (i.e. body composition, fat distribution, pulmonary function, oxygen cost of breathing, cardiorespiratory measures) improved with weight loss; however, the decrease in RPB was not correlated with any of these variables (p>0.05). In conclusion, moderate weight loss was effective in reducing breathlessness on exertion in obese women who experienced DOE at baseline.

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Section: Discussionsupporting

confidence: 93%

Weight loss reduces dyspnea on exertion in obese women

Bernhardt

Babb

2014

Respiratory Physiology & Neurobiology

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“…Thus, STM represents the ability of the respiratory control system to adjust breathing during exercise to accommodate other respiratory stimuli or imposed challenges (such as changes in dead space). First demonstrated in goats (Mitchell, 1990), STM is also present and robust in healthy, younger and older women and men (Wood et al, 2010, 2011; Wood et al, 2008b). Results of the current study extend those prior results to include healthy obese individuals as well as obese patients with OSA demonstrating functioning STM; P ET CO2 is maintained within 2 mmHg.…”

Section: Discussionmentioning

confidence: 95%

Short-term modulation of the ventilatory response to exercise is preserved in obstructive sleep apnea

Bernhardt

Mitchell

Lee³

et al. 2017

Respiratory Physiology & Neurobiology

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Background The ventilatory response to exercise can be transiently adjusted in response to environmentally (e.g., breathing apparatus) or physiologically altered conditions (e.g., respiratory disease), maintaining constant relative arterial PCO2 regulation from rest to exercise (Mitchell and Babb, 2006); this augmentation is called short-term modulation (STM) of the exercise ventilatory response. Obesity and/or obstructive sleep apnea could affect the exercise ventilatory response and the capacity for STM due to chronically increased mechanical and/or ventilatory loads on the respiratory system, and/or recurrent (chronic) intermittent hypoxia experienced during sleep. We hypothesized that: 1) the exercise ventilatory response is augmented in obese OSA patients compared with obese non-OSA adults, and 2) the capacity for STM with added dead space is diminished in obese OSA patients. Methods Nine obese adults with OSA (age: 39 ± 6 yr, BMI: 40 ± 5 kg/m2, AHI: 25 ± 24 events/hr [range 6–73], mean ± SD) and 8 obese adults without OSA (age: 38 ± 10 yr, BMI: 37 ± 6 kg/m2, AHI: 1 ± 2) completed three, 20-min bouts of constant-load submaximal cycling exercise (8 min rest, 6 min at 10 and 30 W) with or without added external dead space (200 or 400 ml; 20 min rest between bouts). Steady-state measurements were made of ventilation (V̇E), oxygen consumption (V̇O2), carbon dioxide production (V̇CO2), and end-tidal PCO2 (PETCO2). The exercise ventilatory response was defined as the slope of the V̇E-V̇CO2 relationship (ΔV̇E/ΔV̇CO2). Results In control (i.e. no added dead space), the exercise ventilatory response was not significantly different between non-OSA and OSA groups (ΔV̇E/ΔV̇CO2 slope: 30.5 ± 4.2 vs 30.5 ± 3.8, p > 0.05); PETCO2 regulation from rest to exercise did not differ between groups (p > 0.05). In trials with added external dead space, ΔV̇E/ΔV̇CO2 increased with increased dead space (p < 0.05) and the PETCO2 change from rest to exercise remained small (<2 mmHg) in both groups, demonstrating STM. There were no significant differences between groups. Conclusions Contrary to our hypotheses: 1) the exercise ventilatory response is not increased in obese OSA patients compared with obese non-OSA adults, and 2) the capacity for STM with added dead space is preserved in obese OSA and non-OSA adults.

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“…[15][16][17][18][19][20][21] In accordance with the Institutional Review Board (University of Texas Southwestern Medical Center, STU 122010-108), all details of the experiments were discussed with the volunteers, and informed consent was obtained before participation. All subjects were selected using the same guidelines, were nonsmokers, and had the same exclusion criteria: history of asthma, cardiovascular disease, musculoskeletal abnormalities, or had participated in regular vigorous exercise for the last 6 months.…”

Section: Methodsmentioning

confidence: 99%

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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The Ventilatory Response to Exercise Does Not Differ Between Obese Women With and Without Dyspnea on Exertion

Cited by 10 publications

References 12 publications

Weight loss reduces dyspnea on exertion in obese women

Weight loss reduces dyspnea on exertion in obese women

Short-term modulation of the ventilatory response to exercise is preserved in obstructive sleep apnea

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

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