New Findings What is the central question of the study? What are the sex differences in ventilatory responses during exercise in adults with obesity? What is the main finding and its importance? Tidal volume and expiratory flows are lower in females when compared with males at higher levels of ventilation despite small increases in end-expiratory lung volumes. Since dyspnoea on exertion is a frequent complaint, particularly in females with obesity, careful attention should be paid to unpleasant respiratory symptoms and mechanical ventilatory constraints while prescribing exercise. Obesity is associated with altered ventilatory responses, which may be exacerbated in females due to the functional consequences of sex-related morphological differences in the respiratory system. This study examined sex differences in ventilatory responses during exercise in adults with obesity. Healthy adults with obesity (n = 73; 48 females) underwent pulmonary function testing, underwater weighing, magnetic resonance imaging (MRI), a graded exercise test to exhaustion, and two constant work rate exercise tests; one at a fixed work rate (60 W for females and 105 W for males) and one at a relative intensity (50% of peak oxygen uptake, V?O2peak${\dot{V}}_{{{\rm{O}}}_{\rm{2}}{\rm{peak}}}$). Metabolic, respiratory and perceptual responses were assessed during exercise. Compared with males, females used a smaller proportion of their ventilatory capacity at peak exercise (69.13 +/- 14.49 vs. 77.41 +/- 17.06% maximum voluntary ventilation, P = 0.0374). Females also utilized a smaller proportion of their forced vital capacity (FVC) at peak exercise (tidal volume: 48.51 +/- 9.29 vs. 54.12 +/- 10.43%FVC, P = 0.0218). End-expiratory lung volumes were 2-4% higher in females compared with males during exercise (P < 0.05), while end-inspiratory lung volumes were similar. Since the males were initiating inspiration from a lower lung volume, they experienced greater expiratory flow limitation during exercise. Ratings of perceived breathlessness during exercise were similar between females and males at comparable levels of ventilation. In summary, sex differences in the manifestations of obesity-related mechanical ventilatory constraints were observed. Since dyspnoea on exertion is a common complaint in patients with obesity, particularly in females, exercise prescriptions should be tailored with the goal of minimizing unpleasant respiratory sensations.

Temporal responses of ratings of perceived breathlessness (RBP) during constant-load and incremental exercise, and during voluntary hyperpnea (EVH) were examined in women with obesity. Following 6 min of constant-load (60W) cycling, 34 women rated RPB >= 4 (+DOE) and 22 women rated RPB <= 2 (-DOE). Both groups completed an incremental cycling test and an EVH test at 40 and 60L/min; RPB was assessed each minute of incremental cycling and at the end of each EVH trial. RPB increased with ventilation during constant-load (+DOE: R-2 =0.86; -DOE: R-2=0.82) and incremental (+DOE: R-2=0.91; -DOE: R-2=0.92) exercise, but + DOE had a greater y-intercept than -DOE (60W: -0.16 +/- 1.53 vs. -0.73 +/- 0.55; incremental: -0.50 +/- 1.40 vs. -1.71 +/- 0.84). Despite matching ventilation, RPB was greater in + DOE at baseline (0.97 +/- 1.14 vs. 0.14 +/- 0.28), 40L/min (2.50 +/- 1.43 vs. 0.98 +/- 0.91), and 60L/min (3.94 +/- 2.19 vs. 2.07 +/- 1.32) during EVH. These findings show that despite linear associations between RPB and ventilation during exercise and voluntary hyperpnea, breathlessness perception at a given ventilatory demand is heightened in +DOE compared with -DOE.

OBJECTIVE:The objective of this paper is to present data on participant recruitment, retention, and weight loss success during a psychophysiological study in women with obesity.METHODS:Volunteers were women with obesity, 20 - 45 yr, with a BMI between 30 - 45 kg/m2. The study was approximately 20 weeks in duration, including a 12-week weight loss program.RESULTS:Recruitment was not completed until 8 months past the original projected date of 12 months. The study was not completed until 11 months past the original projected completion date of 14 months. On average 4.4 ± 2.1 (mean ± SD) volunteers were consented per month (N = 99) and 2.5 ± 1.1 participants started the weight loss program per month. 24% of consented volunteers were lost due to exclusion criteria, withdrawals, and unresponsive behavior before starting the weight loss program. Attrition of participants who started the weight loss program was 45%. Only 11% of those who started the program were unable to lose weight (N = 6).CONCLUSION:Recruiting and/or weight loss success do not always present the most challenging aspects of completing a psychophysiological weight loss intervention. While participant attrition during a weight loss program can occur for a wide range of reasons supportive efforts in the early phases of the intervention may maximize retention.

While the 0-10 Borg scale to rate perceived breathlessness (RPB) is widely used to assess dyspnea on exertion, the repeatability of RPB in women with obesity is unknown. We examined the repeatability of RPB in women with obesity during submaximal constant-load cycling following at least 10 weeks of normal daily life. Seventeen women (37 ± 7 yr; 34.6 ± 4.5 kg/m2) who rated their breathlessness as 3 on the Borg scale (i.e., “moderate”) during 60 W submaximal cycling repeated the same test following 19 ± 9 weeks of normal living. Mean body weight (93.8 ± 16.1 vs. 93.6 ± 116.8 kg, p = 0.94) and RPB (3.0 ± 0.0 vs. 3.1 ± 1.4, p = 0.80) did not differ between pre- and post-normal living periods. We demonstrate that subjective ratings of breathlessness are repeatable for the majority of subjects and can be used to accurately assess DOE during submaximal constant-load cycling in women with obesity.

We investigated the contributions of obesity on multidimensional aspects of dyspnea on exertion (DOE) in patients referred for clinical cardiopulmonary exercise testing (CPET). Ratings of perceived breathlessness (RPB, Borg scale 0-10) were collected in obese (BMI >= 30; n = 47) and nonobese (BMI <= 25; n = 27) patients during two (one lower: similar to 30 W; and one higher: similar to 50 W) 4 - 6 min constant load cycling bouts. Multidimensional dyspnea profiles (MDP) were collected in the final 26 obese and 14 nonobese patients of the sample. RPB was greater (p = 0.05) in obese (3.3 +/- 2.2 vs 2.4 +/- 1.4) at lower work rates, but similar at higher work rates (4.9 +/- 2.2 vs 4.4 +/- 1.8). MDP sensory score including unpleasantness was 4.3 +/- 2.2 in obese vs 2.5 +/- 1.9 in nonobese (p < 0.001). The affective score was 1.9 +/- 2.2 vs 0.7 +/- 0.7, respectively (p < 0.01). Breathing sensations including 'air hunger', 'effort', and 'breathing at lot' were greater (p < 0.05) in obese, making these patients more frustrated/angry (p < 0.05). Obesity should be considered as a potential independent influencing factor that provokes DOE and unpleasantness when assessing breathlessness during CPET.

BACKGROUND: Research has shown that college students exhibit gains in fat mass that are up to 5.5 times greater than their peers of the same age who do not attend college (Mihalopoulos et al, 2008). Because of concerns over increasing rates of obesity, college campuses nationwide are engaging in campaigns designed to target college youth and educate them about the benefits of healthy lifestyle behaviors. In order to implement effective intervention strategies, a clear picture of current student fitness must be acquired. PURPOSE: The purpose of this study was to examine objective measures of body composition and aerobic fitness levels in current first year students of a rural university. METHODS: 24 participants (17F/7M, 18±1yr, 167.5 ±72.0 cm, 67.9±17.1kg, 24.5 ±5.2kg/m2 BMI) underwent dual energy x-ray absorptiometry for body fat determination and performed the Astrand submaximal bicycle ergometer test with metabolic measurements (e.g., VO2), from which estimated VO2max was extrapolated. The International Physical Activity Questionnaire (IPAQ) was administered to gather subjective self-evaluation of weekly exercise volume. RESULTS: The majority of students (13F/4M) fell into the "very poor" category for body fat percentage as defined by ACSM (34±7% in females and 24±10 in males). Five(5F/0M) were classified as "poor", 1 (0F/1M) as "fair", and 3 (1F/2M) as "good". 13 participants were classified as "good" or better on VO2 max and 11as"fair" or worse (female: 42.5±11.2 ml/kg/min and male: 39.0 ±15.7 ml/kg/min). The majority (8F/7M) of participants claimed to engage in a "high" volume of physical activity per week as measured by the IPAQ, while 7 (7F/0M)scored "moderate" and 2 (2F/0M) "low" levels. CONCLUSION: Although BMI average was normal, the majority of students failed to meet body fat standards. It is also interesting that all 7 males in the study scored themselves as "high" on the IPAQ, yet 6 of the 7 scored "poor" or "very poor" in the objective determination of VO2max. Follow-up studies will investigate how these variables change within their first semester and over their entire college life.

IntroductionThe purpose of this study was to examine whether maximal oxygen uptake (V̇O2max) prediction equations based on lean body mass can overcome the confounding effect of fat mass on quantification of cardiorespiratory fitness in children with obesity.MethodsForty‐nine children (23 with obesity; BMI ≥ 95th percentile) completed a dual‐energy x‐ray absorptiometry scan for estimating body composition and incremental maximal and verification exercise tests till volitional exhaustion for estimating V̇O2max. Prediction equations based on lean body mass (LBM) and body mass from Cooper D.M. et al 2016 were used to predict V̇O2max [Boys: (0.059 × LBM) − 0.103; (0.052 × body mass) − 0.266. Girls: (0.055 × LBM)–0.187; (0.037 × body mass) + 0.022].ResultsIn children without obesity, predicted V̇O2max based on body mass was 100 ± 10mL/min higher than predicted V̇O2max based on LBM (P < 0.001). In children with obesity, predicted V̇O2max based on body mass was 906 ± 33mL/min higher than predicted V̇O2max based on LBM (P < 0.001). Predicted V̇O2max based on body mass was more strongly associated with fat mass (r = 0.81) compared with predicted V̇O2max based on LBM (r = 0.51); P<0.001. The V̇O2max vs. LBM slope was similar for children with (0.040 L·min−1·kg−1) and without obesity (0.043 L·min−1·kg−1). Percent predicted V̇O2max based on LBM was 13% lower in children with obesity compared with children without obesity (P < 0.001). Percent predicted V̇O2max based on body mass was 37% lower in children with obesity compared with children without obesity (P < 0.001).ConclusionsReferencing V̇O2max to body mass substantially underestimates cardiorespiratory fitness in children with obesity due to the confounding effect of metabolically inactive fat mass. It would be prudent to measure LBM and reference V̇O2max to LBM for a less biased estimation of cardiorespiratory fitness in children with obesity.Support or Funding InformationThis research was supported by NIH R01 HL136643, Texas Health Presbyterian Hospital Dallas, King Charitable Foundation Trust, and unrestricted funds from Dr. Pepper Snapple.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

We hypothesized that weight loss would ameliorate dyspnea on exertion (DOE) and feelings of unpleasantness related to the DOE in obese men. Eighteen men (34 +/- 7yr, 35 +/- 4 kg/m(2) BMI, mean +/- SD) participated in a 12-week weight loss program. Body composition, pulmonary function, cardiorespiratory measures, DOE, and unpleasantness (visual analog scale) were assessed before and after weight loss. Subjects were grouped by Ratings of Perceived Breathlessness (RPB, Borg 0-10 scale) during submaximal cycling: Ten men rated RPB >= 4 ( + DOE), eight rated RPB 2 <= (-DOE). Subjects lost 10.3 +/- 5.6 kg (9.2 +/- 4.5%) of body weight (n = 18). RPB during submaximal cycling was significantly improved in both groups ( + DOE: 4.1 +/- 0.3-2.8 +/- 1.1; -DOE: 1.3 +/- 0.7 to 0.8 +/- 0.6, p < 0.001). Several submaximal exercise variables (e.g., (V) over dotO(2), (V) over dot(E)) were decreased similarly in both groups (p < 0.01). Unpleasantness associated with the DOE was reduced (p < 0.05). The improved RPB was not significantly correlated with changes in body weight or cardiopulmonary exercise responses (p > 0.05). Moderate weight loss appears to be an effective option to ameliorate DOE and unpleasantness related to DOE in obese men.

INTRODUCTION: Laterality, or lateral dominance may lead to asymmetry in muscle mass and strength, which in turn could lead to differences in stability and balance. Muscular asymmetry and dynamic balance asymmetry have been independently linked with increased injury risk. For example, athletes with >4cm anterior reach distance differences (ΔARD) were found to be at significantly higher risk to incur injuries. However, it is unknown if there is an association between muscle mass asymmetry and dynamic balance. Nor is it known if these factors change throughout the sports’ seasonal periods (i.e., off-, pre-, and post-season). The purpose of this preliminary analysis was to analyze differences between lower body lean mass and dynamic balance in collegiate athletes and to examine if associations exist between the two variables during different seasons. METHODS: NCAA Division II student-athletes were recruited in their respective off- or pre-season. Lean mass was assessed via dual energy x-ray absorptiometry. Dynamic balance was assessed via lower quarter Y Balance Test and ΔARD was calculated. Pearson correlation was used to examine associations. RESULTS: 109 athletes (67W/42M) from six sports have been recruited (see table). There were no significant correlations (p > 0.05) between differences in lower body lean mass and ΔARD in either off- or pre-season (r2=0.003 and r2=0.001, respectively). 51% of athletes in off-season and 48% in pre-season exhibited >4cm ΔARD. CONCLUSION: In this preliminary report, no correlation was found between lower body lean mass asymmetry and dynamic balance asymmetry. Concerning was our finding that about half of the athletes showed dynamic imbalances, indicating higher injury risk. Further data collection will determine the extent of the changes in muscle mass and dynamic balance asymmetry over one full competitive season.

PURPOSE: We have previously shown that weight loss improved dyspnea on exertion in obese, otherwise healthy, women. Dyspnea is a multidimensional symptom comprised of at least two distinct domains: sensory-perceptual (i.e., dyspnea intensity) and affective distress (i.e., unpleasantness and emotional response). Both domains may lead individuals to avoid exercise. In this retrospective study, we investigated the effects of weight loss in obese women and men on these dyspnea domains. |METHODS: Twenty-one participants (12 M/9 F, 33 ± 7 yrs, 169 ± 12 cm, 102 ± 18 kg, 35 ± 4 kg/m2, 41 ± 7% body fat) underwent a 12-week weight loss program. Pre- and post-intervention measurements included a submaximal cycling test at 60W for women and 105W for men. Participants rated their perceived breathlessness (RPB, 0-10 Borg scale) as well as unpleasantness, depression, anxiety, frustration, anger, and fear associated with their breathlessness (visual analog scales, 0-10 cm) at the end of the test. Paired t-tests were used to analyze difference between pre- and post-intervention. RESULTS: Significant decreases were achieved in body weight by 9 ± 4 kg (9 ± 4%), BMI by 3 ± 1 kg/m2, and body fat by 5 ± 10% (p < 0.05). RPB dropped by 1.5 ± 1.8 (p < 0.05). Significant decreases in ratings of unpleasantness (-2.3 ± 2.2), anxiety (-1.2 ± 1.8), frustration (-0.8 ± 1.9), and fear (-0.4 ± 1.0) were observed, while ratings of depression and anger were unchanged. CONCLUSIONS: Moderate weight loss alleviated not only dyspnea on exertion, but also the unpleasantness and negative emotional response related to the dyspnea. Supported by NIH Grant R01 HL096782 and King Charitable Foundation Trust.

PURPOSE: Efficiency refers to the amount of work performed for a given energy consumption. Excess body weight is known to increase resting oxygen uptake, but not net oxygen uptake or mechanical efficiency during non-weight bearing exercise such as cycling in prepubertal children. We examined whether the V˙O2/WR slopes during incremental exercise were affected by changes in body composition after 1 year in normal weight and obese 10-12 year-old children. METHODS: 17 children (9 obese) underwent an incremental exercise test on a cycle ergometer and dual energy x-ray absorptiometry at baseline and at 1-year follow-up. A V˙O2/WR slope was calculated from measured V˙O2 and WR (r2 = 0.97 ± 0.1). No intervention was prescribed during the year between testing. RESULTS: There were no mean differences in the V˙O2/WR slope between normal weight and obese children during the incremental exercise test at baseline or 1-year follow-up (P=0.715). Over 1 year, obese children gained 8.1±4.6kg and normal weight children gained 4.3±1.9kg of body mass (P=0.048). Obese children gained 2.6kg more lean body mass than normal weight children (P=0.018), with no differences in percent fat or fat weight gained over 1 year. There were no significant associations between changes in body mass, percent fat, fat mass, or lean body mass and changes in V˙O2/WR slope in normal weight or obese children. CONCLUSIONS: Muscular efficiency (V˙O2/WR slope) during cycling exercise is similar between normal weight and obese children and does not appear to be related to relatively short-term changes in body composition. Supported by funds from NIH R01HL136643, Texas Health Presbyterian Hospital Dallas, Dr. Pepper Snapple, and King Charitable Foundation TrustFigure 1: V˙O2/WR slope was not different between normal weight and obese children at baseline or at 1-year follow-up.

INTRODUCTION Breathlessness during exercise, or dyspnea on exertion (DOE), is a common complaint in otherwise healthy obese adults. It is possible that the higher perception of breathlessness is due to a higher work of breathing. Thus, we investigated whether obese men with high DOE (+DOE) have a higher work of breathing (i.e., oxygen cost) than obese men with a low DOE (−DOE). METHODS 27 obese men underwent underwater weighing and a 6‐min constant load submaximal cycling exercise at 105 W. They also performed eucapnic voluntary hyperpnea (EVH) to determine the oxygen cost of breathing. Participants were classified as +DOE, if their Rating of Perceived Breathlessness (RPB, Borg 0–10 scale) was ≥ 4 (n = 16) and as −DOE if RPB was ≤ 2 (n = 11) during minute 6 of the exercise test. The oxygen cost of breathing was obtained by calculating the slope of the oxygen uptake (ml/min) vs. ventilation (L/min) relationship at rest and during EVH at 60 and 90 L/min. RPB was also collected during the last minute of each EVH trial. Following the 90 L/min EVH trial, participants were asked to choose the “top 3 descriptors that best describe[d] the respiratory sensations [they] felt during the test” from a list of 15 descriptors. Data were analyzed between groups by independent t‐test. RESULTS There were no significant differences between +DOE and −DOE groups in age, BMI, or body fat percentage, respectively (+DOE: 35 ± 6 yr, 36 ± 5 kg/m 2 , 39 ± 5%; −DOE: 32 ± 6 yr, 35 ± 3 kg/m 2 , 37 ± 6%; mean ± SD, p > 0.05). Breathlessness ratings during each level of EVH was significantly greater in the +DOE than the −DOE group (p < 0.01). However, there was no significant difference in the oxygen cost of breathing between +DOE (2.05 ± 0.63 ml/L) and −DOE (1.99 ± 0.78 ml/L, p > 0.05). Eleven of the 16 men +DOE felt that their breathing required effort or work (only 3 of the 11 men −DOE). CONCLUSIONS The otherwise healthy obese men who rated higher breathlessness during exercise also perceived higher breathlessness during the EVH trials. The increase in the intensity of breathlessness was not due to an increased oxygen cost of breathing. Even though the measured work of breathing was not different, the +DOE group more frequently described their breathing to require more work/effort; this perception of effort may be due to changes in neural transmission in the brain, such as a reduced gating of respiratory sensations related to the work of breathing. Support or Funding Information Supported by NIH Grant R01 HL096782 and King Charitable Foundation Trust. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

PURPOSE: Cardiorespiratory fitness (CRF) is used as a diagnostic and prognostic health indicator for all-cause and cardiovascular disease mortality (Lee et al, 2010). Thus, properly quantifying and interpreting CRF is important for accurate diagnoses. The current EACPR/AHA Scientific Statement includes peak oxygen uptake (VO2peak) both in ml/min/kg and as percent of predicted (Guazzi et al, 2016).We have previously shown, in a small cohort of otherwise healthy obese women (n = 26), that obese adults have normal or slightly reduced CRF (~85% of predicted), depending on the prediction equation used (Lorenzo & Babb, 2012). Here, we wanted to validate our earlier findings in a larger sample of women. METHODS: Obese women underwent hydrostatic weighing to assess body fat percentage, fat mass, and lean body mass. They then completed an incremental cycling test to exhaustion to determine VO2peak. Prediction equations from Riddle et al (R; 1980), Wasserman et al (W; 2005), and Gläser (G; 2010) were used to assess CRF as previously described. Differences between percent predicted VO2peak values derived from the three equations were analyzed using repeated measures ANOVA. RESULTS: Data from 121 women (34 ± 7 yr, 36 ± 4 kg/m2 BMI, 46 ± 5% body fat, 44 ± 9 kg fat mass, 52 ± 6 kg lean body mass, mean ± SD) were analyzed. VO peak (ml/min/kg) was low (18.9 ± 3.0 ml/min/kg) and decreased with increasing body mass, severely penalizing heavier individuals. In fact, applying the current ACSM CRF classification, 113 women would be considered “very poor” and 8 as “poor” (all below the 25th percentile). Mean values of % predicted VO peak were significantly different between equations R and W, and W and G, but not between R and G (R: 92 ± 14%, W: 91 ± 14%, G: 92 ± 14%, p < 0.01). Using a cutoff for low CRF of < 84% of predicted VO2peak, only 27-32% of women fell into this category, depending on the equation used. CONCLUSIONS: The commonly used method of evaluating VO2peak based on body weight (ml/kg/min) is not appropriate in obese individuals; VO2peak as percent of predicted is a better alternative when assessing CRF. Similar to our previous data in a small cohort of otherwise healthy obese women, the current data show that the majority of obese women have normal CRF, independent of the prediction equation used.