Exercise-induced arterial hypoxemia in female masters athletes.

The purpose of the study was to characterize exercise induced arterial hypoxemia (EIAH) in female masters athletes (FMA). We hypothesized that FMA would experience EIAH during treadmill running. Eight FMA (48-57 years) completed pulmonary function testing and an incremental exercise test until exhaustion (V̇O2max⁡ = 45.7 ± 6.5, range:35-54 ml/kg/min). On a separate day, the participants were instrumented with a radial arterial catheter and an esophageal temperature probe. Participants performed three to four constant load exercise tests at 60-70 %, 75 %, 90 %, 95 %, and 100 % of maximal oxygen uptake while sampling arterial blood and recording esophageal temperature. We found that FMA decrease their partial pressure of oxygen (86.0 ± 7.6, range:73-108 mmHg), arterial saturation (96.2 ± 1.2, range:93-98 %), and widen their alveolar to arterial oxygen difference (23.2 ± 8.8, range:5-42 mmHg) during all exercise intensities however, with variability in terms of severity and pattern. Our findings suggest that FMA experience EIAH however aerobic fitness appears unrelated to occurrence or severity (r = 0.13, p = 0.756).

Software development to optimize the minimal detectable difference in human airway images captured using optical coherence tomography.

Optical coherence tomography (OCT) is an imaging methodology that can be used to assess human airways. OCT avoids the harmful effects of ionizing radiation and has a high spatial resolution making it well suited for imaging the structure of small airways. Analysis of OCT airway images has typically been performed manually by tracing the airway with a relatively high coefficient of variation. The purpose of this study was to develop an analysis tool to reduce the inter- and intra-observer reproducibility of OCT and improve the ability to detect differences in airways. OCT images from healthy, young human volunteers were used to develop and test the OCT software. Measurement software was developed to allow the conversion of the original image into a grayscale image and was followed by an enhancement operation to brighten the image, and contour measurement. A total of 140 OCT images, 70 small (<2 mm) and 70 medium (2-4 mm) sized airways were analyzed. The inter- and intraobserver reproducibility of airway measurements ranged for strong to very strong in the small-sized airways. For medium-sized airways the reproducibility was considered moderate. Bland-Altman bias was low between observers and observations for all measures. The minimal detectable differences in the airway measurements with our semi-automated software were lower relative to manual tracing in medium-sized airways. Our software improves the ability to perform quantitative OCT analysis and may help to quantify the extent of airway remodelling in respiratory disease or elite athletes in future studies.

Airway luminal area and the resistive work of breathing during exercise in healthy young females and males.

We examined the relationship between the work of breathing (Wb) during exercise and in vivo measures of airway size in healthy females and males. We hypothesized that sex differences in airway luminal area would explain the larger resistive Wb during exercise in females. Healthy participants (n = 11 females and n = 11 males; 19-30 yr) completed a cycle exercise test to exhaustion where Wb was assessed using an esophageal balloon catheter. On a separate day, each participant underwent a bronchoscopy procedure for optical coherence tomography measures of seven airways. In vivo measures of luminal area were made for the fourth to eighth airway generations. A composite index of airway size was calculated as the sum of the luminal area for each generation, and the total area was calculated based on Weibel's model. We found that index of airway size (males: 37.4 ± 6.3 mm2 vs. females: 27.5 ± 7.4 mm2) and airway area calculated based on Weibel's model (males: 2,274 ± 557 mm2 vs. females: 1,594 ± 389 mm2) were significantly larger in males (both P = 0.003). When minute ventilation was greater than ∼60 L·min-1, the resistive Wb was higher in females. At the highest equivalent flow achieved by all subjects, resistance to inspired flow was larger in females and significantly associated with two measures of airway size in all subjects: index of airway size (r = 0.524, P = 0.012) and Weibel area (r = 0.525, P = 0.012). Our findings suggest that innate sex differences in luminal area result in a greater resistive Wb during exercise in females compared with males.NEW & NOTEWORTHY We hypothesized that the higher resistive work of breathing in females compared with males during high-intensity exercise is due to smaller airways. In vivo measures of the fourth to eighth airway generations made using optical coherence tomography show that females tend to have smaller airway luminal areas of the fourth to sixth airway generations. Sex differences in airway luminal area result in a greater resistive work of breathing during exercise in females compared with males.

Exercise and health-related fitness predictors of chemotherapy completion in breast cancer patients: pooled analysis of two multicenter trials.

PURPOSE: Achieving a higher chemotherapy completion rate is associated with better outcomes in breast cancer patients. We examined the role of exercise and health-related fitness variables in predicting chemotherapy completion in early stage breast cancer patients. METHODS: We pooled data from two large, multicenter, exercise trials that obtained baseline (pre-chemotherapy) measures of exercise and health-related fitness in 543 breast cancer patients initiating adjuvant chemotherapy. Assessments included body composition, cardiovascular fitness, muscular strength, patient-reported physical functioning, and self-reported exercise behavior. Chemotherapy completion was assessed as the average relative dose intensity (RDI) for the originally planned regimen. We used logistic regression analyses with a two-sided p value of < 0.05 to estimate the associations between the predictors and an RDI of ≥ 85%. RESULTS: Overall, 432 of 543 (79.6%) breast cancer patients received an RDI of ≥ 85%. In logistic regression analyses adjusted for significant covariates, patients in the highest 20% vs. lowest 80% of absolute VO2peak were significantly more likely to complete ≥ 85% RDI (89.0% vs. 77.2%; ORadj 2.06, 95% CI 1.07-3.96, p = 0.031). Moreover, patients in the highest 80% vs. lowest 20% of absolute chest strength were significantly more likely to complete ≥ 85% RDI (81.5% vs. 71.4%; ORadj 1.80, 95% CI 1.09-2.98, p = 0.021). CONCLUSIONS: In these exploratory analyses, higher baseline (pre-chemotherapy) cardiovascular fitness and muscular strength were associated with higher rates of chemotherapy completion in early stage breast cancer patients. Aerobic and/or strength training interventions that increase cardiovascular fitness and muscular strength prior to chemotherapy for breast cancer may improve treatment tolerability and outcomes. CLINICAL TRIAL REGISTRATION: START: NCT00115713, June 24, 2005; CARE: NCT00249015, November 7, 2005 ( http://clinicaltrials.gov ).

Impact of Exercise on Chemotherapy Tolerance and Survival in Early-Stage Breast Cancer: A Nonrandomized Controlled Trial.

BACKGROUND: Available preliminary evidence is conflicting on whether exercise can positively influence antineoplastic treatment tolerance and in turn improve survival. PATIENTS AND METHODS: This study compared chemotherapy treatment tolerance and survival among women receiving adjuvant chemotherapy for early-stage breast cancer who participated in a single-arm trial of supervised aerobic and resistance exercise programming versus a historical cohort that did not receive structured exercise programming. RESULTS: The exercise group (EX; n=73) and control group (CTR; n=85) participants were matched on age and treatment and balanced on medical history, cancer diagnosis, and body mass index. Attendance in the EX group was 64% ± 27% of 3 offered sessions per week. For all chemotherapy agents combined, the relative risk (RR) of a chemotherapy dose reduction (RR, 0.78; 95% CI, 0.54-1.11) or delay (RR, 1.05; 95% CI, 0.62-1.80) did not differ between groups. However, the EX group had reduced relative and absolute risks of a dose reduction in doxorubicin by 60% and 18%, respectively. For all agents combined, there were no differences between groups in risk of anemia, neutropenia, or weight gain. In the EX group, dose reductions due to neutropenia (P=.027), other infections (P=.049), and fatigue (P=.037) were less common, whereas mucositis was more common (P=.023), compared with the CTR group. The EX group had reduced relative and absolute risks of weight gain on the docetaxel + cyclophosphamide regimen by 38% and 30%, respectively. After a median follow-up of 70 months (range, 54-84 months), there was no difference between the EX and CTR groups in disease-free survival events (n=8 [11%] vs n=9 [11%], respectively; log-rank test, P=.78) or overall survival events (n=5 [7%] vs n=6 [7%], respectively; log-rank test, P=.974). CONCLUSIONS: Overall, exercise programming during adjuvant chemotherapy does not appear to impact treatment tolerance or survival in women receiving common modern regimens of adjuvant chemotherapy for early-stage breast cancer. However, exercise may provide selective benefits, depending on the treatment regimen received.

Exercise training affects hemodynamics not cardiac function during anthracycline-based chemotherapy.

INTRODUCTION: Preclinical data demonstrate the potential for exercise training to protect against anthracycline-related cardiotoxicity, but this remains to be shown in humans. PURPOSE: To assess whether exercise training during anthracycline-based chemotherapy for treatment of breast cancer affects resting cardiac function and hemodynamics. METHODS: In this prospective, non-randomized controlled study, 26 women who participated in aerobic and resistance training 3×/wk during chemotherapy were compared to 11 women receiving usual care. Two-dimensional echocardiography was performed before and 7-14 days after completion of anthracycline-based chemotherapy. Pre- and post-anthracycline cardiac function and hemodynamic variables were compared within each group with paired t-tests; the change was compared between groups using ANCOVA with adjustment for baseline values. RESULTS: Left ventricular longitudinal strain, volumes, ejection fraction, E/A ratio, and mass did not change in either group. Hemoglobin, hematocrit, and mean arterial pressure decreased significantly from baseline in both groups (all p < 0.05) with no differences between groups. Cardiac output increased in the usual care group only (+ 0.27 ± 0.24 L/min/m2, p < 0.01), which differed significantly from the exercise group (p = 0.03). Systemic vascular resistance (SVR) decreased in both groups (usual care: - 444, p < 0.01; exercise: - 265, dynes/s/cm5, p = 0.01). However, the reduction in SVR was significantly attenuated in the exercise group (p = 0.03) perhaps due to a compensatory decrease in estimated vessel lumen radius. CONCLUSION: Exercise training during anthracycline chemotherapy treatment had no effect on resting cardiac function but appeared to modify hemodynamic responses. Specifically, exercise training attenuated the drop in SVR in response to chemotherapy-related reductions in hematocrit potentially by increasing vessel lumen radius.

Peripheral chemoresponsiveness during exercise in male athletes with exercise-induced arterial hypoxaemia.

NEW FINDINGS: What is the central question of this study? Do highly trained male endurance athletes who develop exercise-induced arterial hypoxaemia (EIAH) demonstrate reduced peripheral chemoresponsiveness during exercise? What is the main finding and its importance? Those with the lowest arterial saturation during exercise have a smaller ventilatory response to hypercapnia during exercise. There was no significant relationship between the hyperoxic ventilatory response and EIAH. The findings suggest that peripheral chemoresponsiveness to hypercapnia during exercise could play a role in the development of EIAH. The findings improve our understanding of the mechanisms that contribute to EIAH. ABSTRACT: Exercise-induced arterial hypoxaemia (EIAH) is characterized by a decrease in arterial oxygen tension and/or saturation during whole-body exercise, which may in part result from inadequate alveolar ventilation. However, the role of peripheral chemoresponsiveness in the development of EIAH is not well established. We hypothesized that those with the most severe EIAH would have an attenuated ventilatory response to hyperoxia and hypercapnia during exercise. To evaluate this, on separate days, we measured ventilatory sensitivity to hyperoxia and separately hypercapnia at rest and during three different exercise intensities (25, 50% of V̇O2max and ventilatory threshold (∼67% of V̇O2max )) in 12 males cyclists ( V̇O2max  = 66.6 ± 4.7 ml kg-1  min-1 ). Subjects were divided into two groups based on their end-exercise arterial oxygen saturation (ear oximetry, SpO2 ): a normal oxyhaemoglobin saturation group (NOS, SpO2  = 93.4 ± 0.4%, n = 5) and a low oxyhaemoglobin saturation group (LOS, SpO2  = 89.9 ± 0.9%, n = 7). There was no difference in V̇O2max (66.4 ± 2.9 vs. 66.8 ± 6.0 ml kg-1  min-1 , respectively, P = 0.9), peak ventilation during maximal exercise (182 ± 15 vs. 197 ± 32 l min-1 , respectively, P = 0.36) or ventilatory response to hyperoxia (P = 0.98) at any exercise intensity between NOS and LOS groups. However, those in the LOS group had a significantly lower ventilatory response to hypercapnia (P = 0.004, (η2  = 0.18). There was also a significant relationship between the mean hypercapnic response and end-exercise SpO2 (r = 0.75, P = 0.009) but not between the mean hyperoxic response and end-exercise SpO2 (r = 0.21, P = 0.51). A blunted hypercapnic ventilatory response may contribute to EIAH in highly trained men due to a failure to increase ventilation sufficiently to offset exercise-induced gas exchange impairments.

Diagnosis of Exercise-induced Bronchoconstriction in Swimmers: Context Matters.

Swimmers have a high prevalence of exercise-induced bronchoconstriction (EIB), which may be associated with repeated exposure to chlorinated pool water. The eucapnic voluntary hyperpnea (EVH) test is used to diagnose EIB; however, it fails to replicate the environmental conditions experienced by swimmers. The relationship between the composition of the EVH inspired gas and the development of EIB from swim exercise remains unclear. PURPOSE: This study aimed to compare the bronchoconstrictive effect of a chlorinated inspirate EVH test and swim test to a laboratory-based EVH test in swimmers. METHODS: Fifteen collegiate swimmers (n = 5 male, n = 10 female; 21 ± 2 yr) completed 3 d of testing in pseudorandom order; a standard EVH test (EVHL), a pool air EVH test (EVHCl), and a swimming test (Swim). Spirometry was measured at baseline, and 3, 5, 10, 15, and 20 min after each test. RESULTS: EVHL elicited a forced expired volume in 1 s (FEV1) fall index of -9.7% ± 6.4% compared with -6.6% ± 9.2% and -3.0% ± 7.5% after EVHCl and Swim, respectively (P < 0.05). Using Bland-Altman analysis, we found good agreement between EVHL and EVHCl (bias = -2.8, r = 0.79; P < 0.05) with poor agreement between EVHL and Swim (bias = -6.7, r = 0.20) and between EVHCl and Swim (bias = -3.9, r = 0.50; both P < 0.05). Forced expired flow between 25% and 75% lung volume and peak expired flow were significantly reduced by the EVHL compared with the EVHCl and Swim tests (P < 0.05). CONCLUSIONS: EVHL elicits a greater forced expired volume in 1-s fall index compared with EVHCl and Swim. The unique aquatic environment of swimmers potentially protects against bronchoconstriction and should be considered in the determination of EIB.

Patterns and predictors of exercise behavior during 24 months of follow-up after a supervised exercise program during breast cancer chemotherapy.

BACKGROUND: Understanding the longer-term exercise behavior of patients with breast cancer after chemotherapy is important to promote sustained exercise. The purpose of the current study was to report the longer-term patterns and predictors of exercise behavior in patients with breast cancer who exercised during chemotherapy. METHODS: In the Combined Aerobic and Resistance Exercise (CARE) Trial, 301 patients with breast cancer were randomized to three different exercise prescriptions during chemotherapy. Exercise behaviors after chemotherapy were self-reported at 6-, 12-, and 24-month follow-up. Exercise patterns were identified by categorizing patients according to which exercise guideline they were meeting (neither, aerobic only, resistance only, or combined) at each of the three follow-up timepoints (64 possible patterns). Predictors of longer-term exercise behavior included physical fitness, patient-reported outcomes, and motivational variables from the theory of planned behavior assessed at postintervention (postchemotherapy). Univariate and multivariate stepwise multinomial logistic regression and linear regression were used for statistical analyses. RESULTS: A total of 264 (88%) participants completed all three follow-up exercise behavior assessments and exhibited 50 different exercise patterns. Postintervention aerobic fitness was the most consistent predictor of longer-term exercise behavior at all three timepoints. For example, higher aerobic fitness (per 1 ml/kg/min) predicted better adherence to the "aerobic only" (OR = 1.09; p = 0.005) and "combined" (OR = 1.12; p < 0.001) guidelines compared to "neither" guideline at 6-month follow-up. Additionally, higher postintervention muscular strength (per 1 kg) was associated with better adherence to the "resistance only" (OR = 1.07; p = 0.025) and "combined" (OR = 1.08; p < 0.001) guidelines compared to "neither" guideline at 24-month follow-up. Finally, lower perceived difficulty (per 1 scale point) was associated with better adherence to the "combined" (OR = 0.62; p = 0.010) and "aerobic only" (OR = 0.58; p = 0.002) guideline compared to the "neither" guideline at the 24-month follow-up. CONCLUSIONS: Our study is the first to show that the longer-term exercise patterns of patients with breast cancer who exercised during chemotherapy are diverse and predicted by physical fitness and motivational variables after chemotherapy. Our novel implications are that improving physical fitness during chemotherapy and applying motivational counseling after chemotherapy may improve longer-term exercise behavior in patients with breast cancer. TRIAL REGISTRATION: (NCT00249015).

"Chemotherapy-periodized" Exercise to Accommodate for Cyclical Variation in Fatigue.

PURPOSE: The purpose of this study was to provide a rationale for "chemotherapy-periodized" exercise by characterizing cyclical variations in fatigue and exercise response across a chemotherapy cycle and comparing exercise adherence during chemotherapy between a prescription that is periodized according to chemotherapy cycle length and a standard linearly progressed prescription. METHODS: Women with breast cancer who were prescribed taxane-based chemotherapy were randomly assigned to a supervised aerobic and resistance exercise program after a chemotherapy-periodized exercise prescription (n = 12) or to usual care during chemotherapy (n = 15). Fatigue and steady state exercise responses were assessed in both groups before the first taxane treatment and across the third treatment (i.e., 0-3 d prior and 3-5 d after the third treatment, and 0-3 d before the fourth treatment) to assess cyclical variations. Adherence to the chemotherapy-periodized exercise prescription was compared with adherence to a standard linear prescription from a prior study in a similar population (n = 51). RESULTS: Fatigue increased from baseline (marginal mean ± standard error: 3.2 ± 0.4) to before the third treatment (4.1 ± 0.4, P = 0.025), then peaked at 3 to 5 d after the third treatment (5.1 ± 0.4, P = 0.001), before recovering before the fourth treatment (4.3 ± 0.5, P = 0.021). The peak in fatigue at 3 to 5 d post-third treatment corresponded to a decrease in steady state exercise oxygen consumption (V˙O2) (P = 0.013). Compared with a standard linear exercise prescription during chemotherapy, a chemotherapy-periodized exercise prescription resulted in higher attendance during the week after chemotherapy (57% ± 30% vs 77% ± 28%, P = 0.04) and overall attendance (63% + 25% vs 78% ± 23%, P = 0.05). CONCLUSIONS: Fatigue and exercise V˙O2 vary across a chemotherapy cycle. A chemotherapy-periodized exercise prescription that accommodates cyclical variations in fatigue may increase adherence to supervised exercise.

Effects of exercise dose and type during breast cancer chemotherapy on longer-term patient-reported outcomes and health-related fitness: A randomized controlled trial.

The Combined Aerobic and Resistance Exercise (CARE) Trial compared different types and doses of exercise performed during breast cancer chemotherapy. Here, we report the longer-term follow-up of patient-reported outcomes, health-related fitness and exercise behavior at 6, 12 and 24 months postintervention. A multicenter trial in Canada randomized 301 breast cancer patients initiating chemotherapy to thrice weekly, supervised exercise consisting of a standard dose of 25-30 min of aerobic exercise (STAN; n = 96), a higher dose of 50-60 min of aerobic exercise (HIGH; n = 101) or a combined dose of 50-60 min of aerobic and resistance exercise (COMB; n = 104) performed for the duration of chemotherapy (median of 17 weeks). Primary outcomes were patient-reported outcomes including quality of life, cancer-related symptoms and psychosocial outcomes. Secondary outcomes were objective health-related fitness (assessed at 12 months only) and self-reported exercise behavior. A total of 269 (89.4%) participants completed patient-reported outcomes at all three follow-up time points and 263 (87.4%) completed the health-related fitness assessment at 12-month follow-up. COMB was significantly superior to (i) STAN for sleep quality at 6-month follow-up (p = 0.027); (ii) HIGH for upper body muscular endurance at 12-month follow-up (p = 0.020); and (iii) HIGH for meeting the resistance exercise guideline at 6-month follow-up (p = 0.006). Moreover, self-reported meeting of the combined exercise guideline during follow-up was significantly associated with better patient-reported outcomes and health-related fitness. Performing combined exercise during and after breast cancer chemotherapy may result in better longer-term patient-reported outcomes and health-related fitness compared to performing aerobic exercise alone.

Effect of Exercise on Taxane Chemotherapy-Induced Peripheral Neuropathy in Women With Breast Cancer: A Randomized Controlled Trial.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting adverse effect of taxanes. We sought to evaluate the effect of exercise on taxane CIPN in women with breast cancer. PATIENTS AND METHODS: Women (n = 27) were randomized to immediate exercise (IE, during taxane chemotherapy) or delayed exercise (DE, after chemotherapy). Supervised aerobic, resistance, and balance training was offered 3 days a week for 8-12 weeks. CIPN symptoms and quality of life were assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ) C30 and CIPN20 (scored from 0 to 100). The percentage of participants reporting moderate to severe sensory symptoms ('3/4' or '4/4' for CIPN20 sensory items) was also evaluated, along with clinical sensory testing at the lower limb (vibration sense and pinprick). Taxane treatment adherence, including relative dose intensity, was extracted from patient medical records. Assessments occurred at: baseline (before taxane chemotherapy), pre-cycle 4 (before the final taxane cycle), the end of chemotherapy, and follow-up (10-15 weeks after chemotherapy). RESULTS: No differences in the EORTC QLQ CIPN20 symptom scores were detected between groups at any time point. At pre-cycle 4, there was a significant difference between groups in patient-reported moderate to severe numbness in the toes or feet (IE: n = 1, 9%, DE: n = 7, 50%, P = .04) and impaired vibration sense in the feet (IE: n = 2, 18%, DE: n = 10, 83%, P < .01). Overall global health status/quality of life was higher in IE compared to DE at the end of chemotherapy (P = .05), yet both groups had worse CIPN20 sensory (Δ24.3 ± 4.6, P < .01) and motor symptom scores (Δ10.5 ± 1.9, P < .01) relative to baseline. By the end of chemotherapy, no differences between groups were found for moderate to severe numbness in the toes or feet (P = 1.0) or impaired vibration sense in the feet (P = .71). More IE participants received ≥ 85% relative dose intensity (IE: n = 12, 100%, DE: n = 10, 67%, P < .05). CONCLUSION: Exercise may attenuate CIPN over the course of taxane chemotherapy and possibly improve taxane adherence in women with breast cancer. These findings, as well as whether exercise can attenuate CIPN by the end of taxane chemotherapy, should be confirmed in larger trials.

A Longitudinal Study of the Association of Clinical Indices of Cardiovascular Autonomic Function with Breast Cancer Treatment and Exercise Training.

BACKGROUND: Cardiovascular autonomic dysfunction is an early marker for cardiovascular disease. Anthracycline chemotherapy and left-sided radiation for breast cancer are associated with negative autonomic function changes. This study's objectives were to characterize changes in, and the association of exercise training with, clinical indices of cardiovascular autonomic function across the trajectory of breast cancer therapy. SUBJECTS, MATERIALS, AND METHODS: Seventy-three patients receiving adjuvant chemotherapy participated to varying degrees in supervised aerobic and resistance exercise during chemotherapy ± radiation and for 20 weeks after. Resting heart rate (HRrest) and blood pressure were measured weekly during chemotherapy. HRrest, exercise heart rate recovery (HRrecovery), and aerobic fitness were measured at enrollment, end of chemotherapy ± radiation, and 10 and 20 weeks after treatment. RESULTS: During chemotherapy, HRrest increased in a parabolic manner within a single treatment and with increasing treatment dose, whereas systolic and diastolic blood pressure decreased linearly across treatments. Tachycardia and hypotension were present in 32%-51% of participants. Factors associated with weekly changes during chemotherapy included receiving anthracyclines or trastuzumab, days since last treatment, hematocrit, and exercise attendance. Receipt of anthracyclines, trastuzumab, and left-sided radiation individually predicted impairments of HRrest and HRrecovery during chemotherapy ± radiation; however, aerobic fitness change and at least twice-weekly exercise attendance predicted improvement. By 10 weeks after treatment, HRrest and blood pressure were not different from prechemotherapy. CONCLUSION: In this study, chemotherapy resulted in increased HRrest and tachycardia, as well as decreased blood pressure and hypotension. Anthracyclines, trastuzumab, and left-sided radiation were associated with HRrest elevations and impairments of HRrecovery, but exercise training at least twice a week appeared to mitigate these changes. IMPLICATIONS FOR PRACTICE: This study characterized changes in clinically accessible measures with well-established prognostic value for cardiovascular disease, and investigated associations with cardiotoxic treatments and the positive influence of exercise. The chemotherapy-related incremental increase in resting heart rate, with tachycardia occurring in one third of patients, and decrease in blood pressure, with hypotension occurring in one half of the patients, is relevant to oncology practitioners for clinical examination or patient report of related symptoms (i.e., dizziness). The weekly dose of two 60-minute sessions of moderate-intensity aerobic and resistance exercise that was identified as protective of cardiovascular autonomic impairments can easily be prescribed to patients by oncologists.

Does competitive swimming affect lung growth?

Whether the large lungs of swimmers result from intensive training or genetic endowment has been widely debated. Given that peak lung growth velocities occur during puberty, this study examined if competitive swimming during puberty affected lung growth. Eleven- to fourteen-year-old healthy female competitive swimmers and controls were assessed before (PRE) and after (POST) one swimming season (7.4 ± 0.5 months). Pulmonary function testing included lung volumes, spirometry, diffusion capacity (DL,CO ), and maximal inspiratory (PIMAX ) and expiratory (PEMAX ) pressures. Ventilatory constraints, including end-expiratory lung volume, expiratory flow limitation, and utilization of ventilatory capacity, were assessed during an incremental cycling test. Swimmers (n = 11) and controls (n = 10) were of similar age, size, and sexual maturity (P > 0.05). However, swimmers compared to controls had a greater total lung capacity (PRE 4.73 ± 0.73 vs. 3.93 ± 0.46, POST 5.08 ± 0.68 vs. 4.19 ± 0.64 L; P < 0.01), peak expiratory flow (PRE 6.48 ± 0.92 vs. 5.70 ± 0.86, POST 6.97 ± 0.84 vs. 6.00 ± 0.77 L·s-1 ; P = 0.03), and PEMAX (P < 0.001). Although DL,CO was greater in swimmers (P = 0.01), differences were attenuated when expressed relative to alveolar volume (PRE 5.14 ± 0.60 vs. 5.44 ± 0.44, POST 4.91 ± 0.56 vs. 5.16 ± 0.38 mL min-1  mmHg-1  L-1 ; P = 0.20). The groups achieved a similar maximal oxygen uptake (P = 0.32), and ventilatory constraints experienced were not different (P > 0.05). Changes over time were not different between groups (P > 0.05). At the initial measurement, pubertal female swimmers had greater lung size, expiratory flows, and indices of respiratory muscle strength, but similar ventilatory constraints while cycling. One competitive swimming season did not further accentuate this enhanced lung size and function or alter ventilatory mechanics, suggesting that competitive swimming during puberty did not affect lung growth.

Predictors of attendance to an oncologist-referred exercise program for women with breast cancer.

PURPOSE: While exercise is associated with numerous benefits in women with breast cancer, adherence to exercise training concurrent to cancer treatment is challenging. We aimed to identify predictors of attendance to an oncologist-referred exercise program offered during and after adjuvant breast cancer treatment. METHODS: Women with early-stage breast cancer receiving chemotherapy (n = 68) enrolled in the Nutrition and Exercise During Adjuvant Treatment (NExT) study. Supervised aerobic and resistance exercise was prescribed three times per week during treatment, then one to two times per week for 20 additional weeks. Predictors of attendance were identified using multivariate linear regression for three phases of the intervention, including during (1) adjuvant chemotherapy, (2) radiation, and (3) 20-weeks post-treatment. RESULTS: Higher baseline quality of life (QoL) predicted higher attendance during chemotherapy (ß = 0.51%, 95 CI: 0.09, 0.93) and radiation (ß = 0.85%, 95 CI: 0.28, 1.41), and higher QoL, measured at the end of treatment, predicted higher attendance post-treatment (ß = 0.81%, 95 CI: 0.34, 1.28). Being employed pre-treatment (ß = 34.08%, 95 CI: 5.71, 62.45) and a personal annual income > $80,000 (ß = 32.70%, 95 CI: 0.85, 64.55) predicted higher attendance during radiation. Being divorced, separated or widowed (ß = - 34.62%, 95 CI: - 56.33, - 12.90), or single (ß = - 25.38%, 95 CI: - 40.64, - 10.13), relative to being married/common-law, and undergoing a second surgery (ß = - 21.37%, 95 CI: - 33.10, - 9.65) predicted lower attendance post-treatment. CONCLUSIONS: Demographic variables, QoL, and receipt of a second surgery significantly predicted attendance throughout the NExT supervised exercise program. These results may help identify individuals with exercise adherence challenges and improve the design of future interventions, including optimizing the timing of program delivery.

Effectiveness of Oncologist-Referred Exercise and Healthy Eating Programming as a Part of Supportive Adjuvant Care for Early Breast Cancer.

BACKGROUND: Randomized trials have established efficacy of supervised exercise training during chemotherapy for breast cancer for numerous health outcomes. The purpose of this study was to assess reach, effectiveness, maintenance, and implementation of an evidence-based exercise and healthy eating program offered within an adjuvant care setting. SUBJECTS, MATERIALS, AND METHODS: Women receiving adjuvant chemotherapy for breast cancer were given a prescription by their oncologist to participate in the Nutrition and Exercise during Adjuvant Treatment (NExT) program. The NExT program consisted of supervised, moderate-intensity, aerobic and resistance exercise three times a week during adjuvant therapy, followed by a step-down in supervised sessions per week for 20 additional weeks, plus one group-based healthy eating session. Usual moderate-to-vigorous physical activity (MVPA) and health-related quality of life (HRQoL) were assessed by questionnaire at baseline, program completion, and one year later, along with measures of satisfaction and safety. RESULTS: Program reach encompassed referral of 53% of eligible patients, 78% uptake (n = 73 enrolled), and 78% retention for the 45.0 ± 8.3-week program. During the program, MVPA increased (116 ± 14 to 154 ± 14 minutes per week, p = .014) and HRQoL did not change. One year later, MVPA (171 ± 24 minutes per week, p = .014) and HRQoL (44 ± 1 to 49 ± 1, p < .001) were significantly higher than baseline. Exercise adherence was 60% ± 26% to three sessions per week during treatment. No major adverse events occurred and injury prevalence did not change relative to baseline. Participants were highly satisfied. CONCLUSION: This oncologist-referred exercise and healthy eating supportive-care program for breast cancer patients receiving chemotherapy was safe, successful in reaching oncologists and patients, and effective for improving MVPA and maintaining HRQoL. IMPLICATIONS FOR PRACTICE: Despite evidence that exercise is both safe and efficacious at improving physical fitness, quality of life, and treatment side effects for individuals with cancer, lifestyle programming is not offered as standard of cancer care. This study describes an oncologist-referred, evidence-based exercise and healthy eating program offered in collaboration with a university as supportive care to women with breast cancer receiving chemotherapy. The program was well received by oncologists and patients, safe, and relatively inexpensive to operate. Importantly, there was a significant positive impact on physical activity levels and health-related quality of life lasting for 2 years after initiation of therapy.

Exercise Prescription and Adherence for Breast Cancer: One Size Does Not FITT All.

PURPOSE: To prospectively assess adherence to oncologist-referred, exercise programming consistent with current recommendations for cancer survivors among women with early breast cancer across the trajectory of adjuvant treatment. METHODS: Sixty-eight women participated in supervised, hour-long, moderate-intensity, aerobic, and resistance exercise thrice per week during adjuvant chemotherapy ± radiation, with a step-down in frequency for 20 additional weeks. Adherence to exercise frequency (i.e., attendance), intensity, and time/duration, and barriers to adherence were tracked and compared during chemotherapy versus radiation, and during treatment (chemotherapy plus radiation, if received) versus after treatment. RESULTS: Attendance decreased with cumulative chemotherapy dose (cycles 1-2 vs cycles 3-8, cycle 3 vs cycles 7-8, all P ≤ 0.05) and was lower during chemotherapy than radiation (64% ± 25% vs 71% ± 32%, P = 0.02) and after treatment than during treatment (P < 0.01). Adherence to exercise intensity trended toward being higher during chemotherapy than radiation (69% ± 23% vs 51% ± 38%, P = 0.06) and was higher during than after treatment (P = 0.01). Adherence to duration did not differ with treatment. Overall adherence to the resistance prescription was poor, but was higher during chemotherapy than radiation (57% ± 23% vs 34% ± 39%, P < 0.01) and was not different during than after treatment. The most common barriers to attendance during treatment were cancer-related (e.g., symptoms, appointments), and after treatment were life-related (e.g., vacation, work). CONCLUSIONS: Adherence to supervised exercise delivered in a real-world clinical setting varies among breast cancer patients and across the treatment trajectory. Behavioral strategies and individualization in exercise prescriptions to improve adherence are especially important for later chemotherapy cycles, after treatment, and for resistance exercise.

Effects of macro- and micronutrients on exercise-induced hepcidin response in highly trained endurance athletes.

Iron deficiency has ergolytic effects on athletic performance. Exercise-induced inflammation impedes iron absorption in the digestive tract by upregulating the expression of the iron regulatory protein, hepcidin. Limited research indicates the potential of specific macro- and micronutrients on blunting exercise-induced hepcidin. Therefore, we investigated the effects of postexercise supplementation with protein and carbohydrate (CHO) and vitamins D3 and K2 on the postexercise hepcidin response. Ten highly trained male cyclists (age: 26.9 ± 6.4 years; maximal oxygen uptake: 67.4 ± 4.4 mL·kg-1·min-1 completed 4 cycling sessions in a randomized, placebo-controlled, single-blinded, triple-crossover study. Experimental days consisted of an 8-min warm-up at 50% power output at maximal oxygen uptake, followed by 8 × 3-min intervals at 85% power output at maximal oxygen uptake with 1.5 min at 60% power output at maximal oxygen uptake between each interval. Blood samples were collected pre- and postexercise, and at 3 h postexercise. Three different drinks consisting of CHO (75 g) and protein (25 g) with (VPRO) or without (PRO) vitamins D3 (5000 IU) and K2 (1000 µg), or a zero-calorie control drink (PLA) were consumed immediately after the postexercise blood sample. Results showed that the postexercise drinks had no significant (p ≥ 0.05) effect on any biomarker measured. There was a significant (p < 0.05) increase in hepcidin and interleukin-6 following intense cycling intervals in the participants. Hepcidin increased significantly (p < 0.05) from baseline (nmol·L-1: 9.94 ± 8.93, 14.18 ± 14.90, 10.44 ± 14.62) to 3 h postexercise (nmol·L-1: 22.27 ± 13.41, 25.44 ± 11.91, 22.57 ± 15.57) in VPRO, PRO, and PLA, respectively. Contrary to our hypothesis, the drink compositions used did not blunt the postexercise hepcidin response in highly trained athletes.

Influence of inspiratory resistive loading on expiratory muscle fatigue in healthy humans.

NEW FINDINGS: What is the central question of this study? This study is the first to measure objectively both inspiratory and expiratory muscle fatigue after inspiratory resistive loading to determine whether the expiratory muscles are activated to the point of fatigue when specifically loading the inspiratory muscles. What is the main finding and its importance? The absence of abdominal muscle fatigue suggests that future studies attempting to understand the neural and circulatory consequences of diaphragm fatigue can use inspiratory resistive loading without considering the confounding effects of abdominal muscle fatigue. Expiratory resistive loading elicits inspiratory as well as expiratory muscle fatigue, suggesting parallel coactivation of the inspiratory muscles during expiration. It is unknown whether the expiratory muscles are likewise coactivated to the point of fatigue during inspiratory resistive loading (IRL). The purpose of this study was to determine whether IRL elicits expiratory as well as inspiratory muscle fatigue. Healthy male subjects (n = 9) underwent isocapnic IRL (60% maximal inspiratory pressure, 15 breaths min-1 , 0.7 inspiratory duty cycle) to task failure. Abdominal and diaphragm contractile function was assessed at baseline and at 3, 15 and 30 min post-IRL by measuring gastric twitch pressure (Pga,tw ) and transdiaphragmatic twitch pressure (Pdi,tw ) in response to potentiated magnetic stimulation of the thoracic and phrenic nerves, respectively. Fatigue was defined as a significant reduction from baseline in Pga,tw or Pdi,tw . Throughout IRL, there was a time-dependent increase in cardiac frequency and mean arterial blood pressure, suggesting activation of the respiratory muscle metaboreflex. The Pdi,tw was significantly lower than baseline (34.3 ± 9.6 cmH2 O) at 3 (23.2 ± 5.7 cmH2 O, P < 0.001), 15 (24.2 ± 5.1 cmH2 O, P < 0.001) and 30 min post-IRL (26.3 ± 6.0 cmH2 O, P < 0.001). The Pga,tw was not significantly different from baseline (37.6 ± 17.1 cmH2 O) at 3 (36.5 ± 14.6 cmH2 O), 15 (33.7 ± 12.4 cmH2 O) and 30 min post-IRL (32.9 ± 11.3 cmH2 O). Inspiratory resistive loading elicits objective evidence of diaphragm, but not abdominal, muscle fatigue. Agonist-antagonist interactions for the respiratory muscles appear to be more important during expiratory versus inspiratory loading.

Impact of resistance and aerobic exercise on sarcopenia and dynapenia in breast cancer patients receiving adjuvant chemotherapy: a multicenter randomized controlled trial.

The purpose of this study was to conduct an exploratory analysis of the START examining the effects of resistance exercise training (RET) and aerobic exercise training (AET) on sarcopenia, dynapenia, and associated quality of life (QoL) changes in breast cancer (BC) patients receiving adjuvant chemotherapy. Participants were randomized to usual care (UC) (n = 70), AET (n = 64), or RET (n = 66) for the duration of chemotherapy. Measures of sarcopenia [skeletal muscle index (SMI)] and dynapenia [upper extremity (UE) and lower extremity (LE) muscle dysfunction (MD)] were normalized relative to age-/sex-based clinical cut-points. QoL was assessed by the Functional Assessment of Cancer Therapy-Anemia (FACT-An) scales. At baseline, 25.5 % of BC patients were sarcopenic and 54.5 % were dynapenic with both conditions associated with poorer QoL. ANCOVAs showed significant differences favoring RET over UC for SMI (0.32 kg/m(2); p = 0.017), UE-MD (0.12 kg/kg; p < 0.001), and LE-MD (0.27 kg/kg; p < 0.001). Chi-square analyses revealed significant effects of RET, compared to UC/AET combined, on reversing sarcopenia (p = 0.039) and dynapenia (p = 0.019). The reversal of sarcopenia was associated with clinically relevant improvements in the FACT-An (11.7 points [95 % confidence interval (CI) -4.2 to 27.6]), the Trial Outcome Index-Anemia (10.0 points [95 % CI -4.0 to 24.1]), and fatigue (5.3 points [95 % CI -1.5 to 12.1]). Early-stage BC patients initiating adjuvant chemotherapy have higher than expected rates of sarcopenia and dynapenia which are associated with poorer QoL. RET during adjuvant chemotherapy resulted in the reversal of both sarcopenia and dynapenia; however, only the reversal of sarcopenia was associated with clinically meaningful improvements in QoL.