Leveraging Spaceflight to Advance Cardiovascular Research on Earth.

The direct (eg, radiation, microgravity) and indirect (eg, lifestyle perturbations) effects of spaceflight extend across multiple systems resulting in whole-organism cardiovascular deconditioning. For over 50 years, National Aeronautics and Space Administration has continually enhanced a countermeasures program designed to characterize and offset the adverse cardiovascular consequences of spaceflight. In this review, we provide a historical overview of research evaluating the effects of spaceflight on cardiovascular health in astronauts and outline mechanisms underpinning spaceflight-related cardiovascular alterations. We also discuss how spaceflight could be leveraged for aging, industry, and model systems such as human induced pluripotent stem cell-derived cardiomyocytes, organoid, and organ-on-a-chip technologies. Finally, we outline the increasing opportunities for scientists and clinicians to engage in cardiovascular research in space and on Earth.

Exercise before, during, and after Hospitalization for Allogeneic Hematological Stem Cell Transplant: A Feasibility Randomized Controlled Trial.

People with cancer who undergo allogeneic hematological stem cell transplant (allo-HSCT) experience significant deconditioning that can compromise quality of life. Exercise has shown to be beneficial before or after allo-HSCT; however, little is known about exercise therapy delivered across the continuum of care. We conducted a feasibility randomized controlled trial of exercise delivered prior to admission, during the inpatient stay, and after discharge versus control in people with planned allo-HSCT. Feasibility was assessed via recruitment and retention rates, the incidence of adverse events, and adherence to the exercise prescription. Estimates of efficacy were measured at baseline, one week prior to hospital admission, and 100 days and one year after transplant. The recruitment and retention rates were 20% and 33%, respectively. One serious adverse event occurred during the baseline six-minute walk test that precluded participation in the study and no adverse events were associated with the intervention. From baseline to pre-transplant, the intervention group improved six-minute walk test distances by 45 m (95% CI: -18.0 to 108.7)-a finding that warrants further investigation with an adequately powered trial. Our study contributes important feasibility considerations and pilot data for future exercise intervention research in allo-HSCT recipients.

Aerobic capacity attainment and reasons for cardiopulmonary exercise test termination in people with cancer: a descriptive, retrospective analysis from a single laboratory.

PURPOSE: Aerobic exercise prescriptions in clinical populations commonly involve target intensities based on cardiopulmonary exercise tests (CPET). CPETs are often discontinued prior to a patient achieving true maximum oxygen consumption (VO2 max) which can adversely affect exercise dose and efficacy monitoring; however, reasons for early discontinuation are poorly reported. Accordingly, we explored the CPET termination reasons in persons with cancer participating in exercise intervention studies. METHODS: This study comprised of an exploratory, descriptive analysis of retrospective CPET data (VO2 and anaerobic threshold) and termination reasons in a convenience sample of people with cancer participating in exercise intervention studies in a single laboratory. CPETs were standardized using the modified Bruce treadmill protocol with expired gas collection and analysis using a metabolic cart. VO2 max was considered "met" when participants demonstrated (a) oxygen consumption plateau or (b) two of the following criteria: rating of perceived exertion ≥ 9/10, respiratory exchange ratio ≥ 1.15, and/or heart rate of 95% of age-predicted maximum. The frequency and distribution of reasons for test termination relative to the number of CPET exposures for the participants were reported. RESULTS: Forty-four participants engaged in exercise studies between February 2016 and March 2018 provided data for the analysis. Participants completed up to three CPETs during this period (total of 78 CPETs in the current analysis). Eighty-six percent of all CPETs were terminated prior to achieving VO2 max verification criteria and no tests resulted in an oxygen consumption plateau. For those that did not demonstrate achievement of VO2 max verification criteria, reasons for discontinuation were distributed as follows: equipment discomfort-49%, volitional peak-36%, and physical discomfort-14.9%. For those who met VO2 max criteria, volitional peak was the most common reason for test termination (45.5%), followed by physical discomfort (36.4%), and equipment discomfort (18.2%). CONCLUSIONS: In our sample of cancer survivors, VO2 max criteria were infrequently met with equipment discomfort being a primary reason for participant-driven test termination. Protocol and equipment considerations are necessary for interpretation and application of CPET findings in clinical practice.

Multisystem Toxicity in Cancer: Lessons from NASA's Countermeasures Program.

Astronauts and cancer patients are subject to similar multisystem physiological toxicities. Over the past sixty years, NASA developed a state-of-the-art countermeasures program (CMP) to characterize and mitigate the physiological consequences of spaceflight. Here, we propose a NASA-modeled CMP to elucidate and abrogate physiological toxicities in patients with cancer.

Impact of Self-Reported Exercise on Recounted Levels of Fatigue and Anxiety in Early-Stage Breast Cancer Radiation Therapy Patients.

PURPOSE: Exercise may be an alternative strategy to helping early-stage breast cancer (ESBC) patients manage their cancer-related fatigue and anxiety during radiation therapy. This observational study aims to investigate the impact of self-reported exercise on fatigue and anxiety levels pre (T0), mid (T1), and post (T2) radiation therapy in patients with ESBC. METHODS: Following informed consent, subjects completed three standardized questionnaires measuring physical activity, fatigue/quality of life, and anxiety at T0, T1, and T2. RESULTS: A total of 58 female patients (57 ± 9 years) completed this study. Mean activity level at T0 was 2548 (3292) metabolic equivalent units (METs), T1 was 3072 (3974) METs, and T2 was 2963 (2442) METs. There was no significant change between the three time points with measures of physical activity. Many patients moved from the moderately active group at T0 to the active group at T1. The mean T0 score using the quality of life questionnaire was 38.97 (11.30), T1 was 36.93 (11.69), and T2 was 35.36 (11.18). There was no significant change between the three time points with measures of quality of life (P = .211). There was statistical significance at P = .025 at T1 for lower quality of life compared to T0 across all exercise types. There was also statistical significance at P = .026 at T1 for the active group with higher quality of life compared to the inactive one. All three physical activity categories showed a decline in quality of life scores over time. Anxiety decreased between the three time point measurements. Mean T0 score for anxiety was 47.33 (5.95), T1 was 43.16 (6.49), and T2 was 38.48 (8.46). The interaction of exercise level and time is not significant for anxiety (P = .91). There was statistical significance (P = .015) for anxiety at T2 compared to T1 across exercise types. DISCUSSION: This study demonstrated that ESBC patients showed signs of fatigue and anxiety while undergoing radiation therapy regardless of self-reported exercise measured by a physical activity questionnaire. Several trends were observed that showed improved outcomes for patients consistent with previously published studies. The present study highlights a nonsignificant change in fatigue. As fatigue is one of the main side effects from radiation, it may be difficult to demonstrate significance. There are some studies in the field that demonstrate significance between fatigue and exercise with larger sample sizes. The results also highlight a decrease in anxiety from the baseline to the end of treatment. It is postulated that patients become less anxious as treatment progresses due to familiarity of a routine. The present study is limited by several factors including sample size and the study not being a randomized controlled one. CONCLUSIONS: Exercise may reduce anxiety during radiation treatment for ESBC patients. Further investigation is required to assess the impact of fatigue.

The Effect of Cardiac Rehabilitation in Men With and Without Prostate Cancer: A Retrospective, Comparative Cohort Study.

BACKGROUND: Men with prostate cancer (PCa) may be referred to cardiac rehabilitation (CR) following a significant cardiac event, but it is unknown if these men have different effects of CR from men without a history of PCa. PURPOSE: To compare the effect of CR on cardiorespiratory fitness (VO2peak), body fat percentage, and body mass index in men with and without a history of PCa. METHODS: CR participants with PCa were retrospectively compared with a cohort matched on age, clinical indication for CR, and date of referral to the CR program. Participants completed the standardized CR program at the Toronto Rehabilitation Institute, including 1 weekly supervised group session and 4 additional weekly home sessions including aerobic and resistance training for 26 weeks. RESULTS: Twenty-seven (n = 27) men with PCa were identified and matched 1∶1 with controls. VO2peak increased in the PCa group (16.9 [5.1]-19.6 [6.2] mL·kg-1·min-1; Δ 2.7 mL·kg-1·min-1, P < .05) and in the control group (16.4 [4.2]-20.2 [5.8] mL·kg-1·min-1; Δ 3.8 mL·kg-1·min-1, P < .05) as a result of engaging in CR. There were no significant between-group differences in the postintervention outcomes (P > .05). CONCLUSIONS: Men with and without PCa experience comparable benefits following CR completion.

The Cardiac Rehabilitation Model Improves Fitness, Quality of Life, and Depression in Breast Cancer Survivors.

PURPOSE: Exercise is a demonstrated, therapeutic strategy for cancer survivors to minimize many treatment-induced side effects and may decrease risk of recurrence. Nonetheless, structured programs that combine exercise and education are not yet standardized within cancer care. The Health, Exercise, Active Living, Therapeutic lifestyle (HEALTh) program is a clinical exercise program based on the established cardiac rehabilitation model, but customized for female breast cancer survivors. This study assessed the effects of a cardiac rehabilitation program on cardiorespiratory fitness, quality of life, and depressive symptoms in breast cancer survivors. METHODS: Charts were reviewed to evaluate the cardiac rehabilitation model. The program consisted of 1 weekly supervised session for 22 group sessions. Each patient was provided with personalized aerobic and resistance exercises plus 12 group educational sessions to encourage behavioral adoption to a healthy lifestyle. Cardiorespiratory fitness (direct (Equation is included in full-text article.)O2peak), quality of life (Short Form-36 Health Status [SF-36] and Functional Assessment of Cancer Therapy-Breast [FACT-B]), and depression (Centre of Epidemiological Studies Depression [CES-D]) were assessed at baseline and after program completion. RESULTS: Two hundred seventy-four files were accessed with 152 eligible files analyzed. Baseline cardiorespiratory fitness and quality-of-life values were below population norms. Program adherence was 66.6%. Cardiorespiratory fitness improved by 14% (21 ± 6 to 24 ± 7 mL/kg/min, P < .001), with significant improvements in quality of life (P < .001) and depression scores (P = .019). Bodily pain was the only domain not significantly affected (P = .311). CONCLUSION: The cardiac rehabilitation model improved physical and mental health in breast cancer survivors. These results provide support for the collaborative effort between cardiology and oncology to improve patient care across the cancer care continuum.

Motivation for Different Types and Doses of Exercise During Breast Cancer Chemotherapy: a Randomized Controlled Trial.

BACKGROUND: Exercise is beneficial for breast cancer patients during chemotherapy, but their motivation to perform different types and doses of exercise is unknown. PURPOSE: The purpose of this study was to examine the anticipated and experienced motivation of breast cancer patients before and after three different exercise programs during chemotherapy. METHODS: Breast cancer patients initiating chemotherapy (N = 301) were randomized to a standard dose of 25-30 min of aerobic exercise, a higher dose of 50-60 min of aerobic exercise, or a combined dose of 50-60 min of aerobic and resistance exercise. Patient preference and motivational outcomes from the theory of planned behavior (i.e., perceived benefit, enjoyment, support, difficulty, and motivation) were assessed before and after the interventions. RESULTS: At pre-randomization, breast cancer patients were significantly (p < 0.001) more likely to prefer the combined program (80.1 %); however, after the interventions there was a significant (p < 0.001) increase in the number of patients preferring the high volume program and having no preference. At pre-randomization, breast cancer patients anticipated more favorable motivational outcomes for the combined program and less favorable motivational outcomes for the high volume program (all p < 0.001). After the interventions, the motivational outcomes experienced exceeded the anticipated motivational outcomes significantly more in the high volume group than the standard or combined groups. CONCLUSIONS: Anticipated motivational outcomes for different types and doses of exercise during chemotherapy varied considerably at pre-randomization, but the motivational outcomes experienced after the three interventions were similar. Clinicians can recommend any of the three exercise interventions to breast cancer patients knowing that positive motivational outcomes will result. Clinicaltrials.gov identifier: NCT00249015 .

Interval versus continuous aerobic exercise training in breast cancer survivors--a pilot RCT.

BACKGROUND: Exercise therapy is being explored in a variety of cancer populations to counteract treatment-related deconditioning. Higher intensity interval protocols are being prescribed to improve physical function and attenuate surrogates of comorbidity in non-cancer populations. The purpose of this study is to explore the safety of higher intensity exercise stimuli on cardiorespiratory fitness (VO2peak) in breast cancer survivors. METHODS: Postmenopausal breast cancer survivors were randomized into three groups: supervised aerobic interval training (AIT), supervised continuous moderate exercise training (CMT), and an unsupervised control group (CON). For 6 weeks, AIT exercised between 70 and 100% VO2peak, while CMT exercised between 60 and 70% VO2peak. Both groups followed a matched-work design. RESULTS: Thirty-three participants completed the study (age, 57.2 (9) years; weight, 67.6 (12) kg) with no adverse advents. Between-group baseline values were non-significant. VO2peak at baseline (25.3 (5.4) mL·kg(-1)·min(-1)) was below population norms. Compared to CON, cardiorespiratory fitness improved in AIT and CMT by 12% (P < 0.001) with no significant difference between exercise groups. AIT had a greater influence on lower extremity strength (P = 0.026) and body weight (P = 0.031). CONCLUSION: This pilot study provides evidence that similar to CMT, AIT can safely increase VO2peak in a small group of breast cancer survivors. Further exploration of the benefits of implementing higher intensity training protocols is warranted.

Predictors of adherence to different types and doses of supervised exercise during breast cancer chemotherapy.

BACKGROUND: Exercise is beneficial for breast cancer patients during chemotherapy but adherence to different types and doses of exercise is a challenge. The purpose of this study was to examine predictors of adherence to different types and doses of exercise during breast cancer chemotherapy in a multicenter randomized controlled trial. METHODS: Breast cancer patients in Edmonton, Vancouver, and Ottawa, Canada receiving chemotherapy (N = 301) were randomized to a standard dose of 25-30 minutes of aerobic exercise (STAN), a higher dose of 50-60 minutes of aerobic exercise (HIGH), or a higher dose of 50-60 minutes of combined aerobic and resistance exercise (COMB). Predictors included demographic, medical, fitness, and quality of life variables. Exercise adherence was measured as the percentage of supervised exercise sessions completed. RESULTS: Overall adherence to the supervised exercise sessions was 73% (SD = 24%). In a multivariate regression model, six independent predictors explained 26.4% (p < 0.001) of the variance in exercise adherence. Higher exercise adherence was achieved by breast cancer patients in Vancouver (p < 0.001), with fewer endocrine symptoms (p = 0.009), randomized to STAN (p = 0.009), with fewer exercise limitations (p = 0.009), receiving shorter chemotherapy protocols (p = 0.015), and with higher VO2peak (p = 0.017). Disease stage (p for interaction = 0.015) and body mass index (p for interaction = 0.030) interacted with group assignment to predict adherence. For disease stage, patients with stage I/IIa disease adhered equally well to all three exercise interventions whereas patients with stage IIb/III disease adhered better to the STAN intervention than the two higher dose exercise interventions. For body mass index, healthy weight patients adhered equally well to all three exercise interventions whereas overweight patients adhered best to STAN and worst to COMB; and obese patients adhered best to STAN and worst to HIGH. CONCLUSIONS: Determinants of exercise adherence in breast cancer patients receiving chemotherapy are multidisciplinary and may vary by the exercise prescription.

A multicenter randomized trial of the effects of exercise dose and type on psychosocial distress in breast cancer patients undergoing chemotherapy.

BACKGROUND: Exercise may improve psychosocial distress in patients with cancer; however, few studies have examined the effects of different types or doses of exercise, or whether exercise effects are related to baseline depression levels. METHODS: In a multicenter trial in Canada, we randomized 301 patients with breast cancer initiating chemotherapy to thrice weekly, supervised exercise consisting of either a standard dose of 25 to 30 minutes of aerobic exercise (STAN; n = 96), a higher dose of 50 to 60 minutes of aerobic exercise (HIGH; n = 101), or a combined dose of 50 to 60 minutes of aerobic and resistance exercise (COMB; n = 104). The primary endpoint was depression assessed by the Center for Epidemiological Studies-Depression scale at baseline, twice during chemotherapy, and postchemotherapy. Secondary endpoints were anxiety, perceived stress, and self-esteem. RESULTS: Repeated measures ANOVA indicated that neither HIGH [mean difference = -0.9; 95% confidence interval (CI), +0.0 to -1.8; P = 0.061] nor COMB (mean difference = -0.4; 95% CI, +0.5 to -1.3; P = 0.36) was superior to STAN for managing depressive symptoms. In a planned subgroup analysis, there was a significant interaction with baseline depression levels (P interaction = 0.027) indicating that COMB and HIGH were effective for managing depressive symptoms in patients with clinical levels of depressive symptoms at baseline. CONCLUSIONS: Compared with a standard volume of aerobic exercise, higher volumes of exercise did not help manage depressive symptoms in unselected patients with breast cancer receiving chemotherapy, but they were effective in patients with clinical levels of depressive symptoms at baseline. IMPACT: A phase III exercise trial targeting depressed patients with breast cancer is warranted.

Effects of exercise dose and type on sleep quality in breast cancer patients receiving chemotherapy: a multicenter randomized trial.

To examine the effects of different doses and types of exercise on sleep quality in breast cancer patients receiving chemotherapy. A multicenter trial in Canada randomized 301 breast cancer patients between 2008 and 2011 to thrice weekly, supervised exercise during chemotherapy consisting of either 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). The secondary sleep outcomes in the trial were assessed by the Pittsburgh Sleep Quality Index (PSQI) at baseline, twice during chemotherapy, and postchemotherapy. We analyzed the global PSQI and the component scores. Repeated measures analyses of variance indicated that the HIGH group was statistically superior to the STAN group for global sleep quality (mean group difference = -0.90; 95 % CI -0.05 to -1.76; p = 0.039) as well as subjective sleep quality (p = 0.028) and sleep latency (p = 0.049). The COMB group was borderline statistically superior to the STAN group for global sleep quality (mean group difference = -0.76; 95 % CI +0.11 to -1.62; p = 0.085) as well as sleep duration (p = 0.051); and statistically superior for sleep efficiency (p = 0.040), and percentage of poor sleepers (p = 0.045). Compared to a standard volume of aerobic exercise, higher volumes of both aerobic and combined exercise improved some aspects of sleep quality during breast cancer chemotherapy. Exercise may be an attractive option to manage sleep dysfunction in cancer patients during chemotherapy.

Effects of exercise dose and type during breast cancer chemotherapy: multicenter randomized trial.

BACKGROUND: Exercise improves physical functioning and symptom management during breast cancer chemotherapy, but the effects of different doses and types of exercise are unknown. METHODS: A multicenter trial in Canada randomized 301 breast cancer patients to thrice-weekly supervised exercise during chemotherapy consisting of either a standard dose of 25 to 30 minutes of aerobic exercise (STAN; n = 96), a higher dose of 50 to 60 minutes of aerobic exercise (HIGH; n = 101), or a combined dose of 50 to 60 minutes of aerobic and resistance exercise (COMB; n = 104). The primary endpoint was physical functioning assessed by the Medical Outcomes Survey-Short Form (SF)-36. Secondary endpoints were other physical functioning scales, symptoms, fitness, and chemotherapy completion. All statistical tests were linear mixed model analyses, and the P values were two-sided. RESULTS: Follow-up assessment of patient-reported outcomes was 99.0%. Adjusted linear mixed-model analyses showed that neither HIGH (+0.8; 95% confidence interval [CI] = -0.8 to 2.4; P = .30) nor COMB (+0.5; 95% CI = -1.1 to 2.1; P = .52] were superior to STAN for the primary outcome. In secondary analyses not adjusted for multiple comparisons, HIGH was superior to STAN for the SF-36 physical component summary (P = .04), SF-36 bodily pain (P = .02), and endocrine symptoms (P = .02). COMB was superior to STAN for endocrine symptoms (P = .009) and superior to STAN (P < .001) and HIGH (P < .001) for muscular strength. HIGH was superior to COMB for the SF-36 bodily pain (P = .04) and aerobic fitness (P = .03). No differences emerged for body composition or chemotherapy completion. CONCLUSIONS: A higher volume of aerobic or combined exercise is achievable and safe during breast cancer chemotherapy and may manage declines in physical functioning and worsening symptoms better than standard volumes.

Optimal mode for maximal aerobic exercise testing in breast cancer survivors.

PURPOSE: To determine which mode of exercise is preferred by breast cancer survivors and to evaluate this response between graded exercise testing on a treadmill and on a cycle ergometer. METHODS: Twelve breast cancer survivors completed 2 maximal aerobic stress tests on separate days. The women completed a ramp protocol on an electronically braked cycle ergometer and an incremental step protocol on a treadmill to volitional fatigue. Test order was randomized. Expired gases were collected for the determination of peak aerobic capacity (Vo (2peak)). RESULTS: Exercise mode had a significant effect on the graded exercise response in breast cancer survivors, P = .003. Treadmill Vo (2peak) was significantly greater than bike Vo (2peak) (28.7 ± 4.7 vs 23.9 ± 4.7 mL/min/kg, respectively, P = .003) and VE(max) was equivalent between exercise modes (P = .731). Maximal heart rate was significantly higher by 11 bpm during the treadmill protocol (P = .004), and Ve/VCo (2) exhibited possible mode dependency (P = .018). CONCLUSION: This patient population felt more comfortable and produced significantly greater Vo2(peak) values using the treadmill protocol. These results discuss the potential implications concerning the design and interpretation of exercise interventions for breast cancer survivors.

Hemoglobin and aerobic fitness changes with supervised exercise training in breast cancer patients receiving chemotherapy.

BACKGROUND: Aerobic exercise training (AET) is known to increase RBC production; however, this has not been evaluated in breast cancer patients undergoing adjuvant chemotherapy. The purpose of this study was to examine the changes in hemoglobin (Hb) levels in the Supervised Trial of Aerobic versus Resistance Training (START) and to determine its association with changes in VO(2peak). METHODS: Two hundred and forty-two breast cancer patients initiating chemotherapy were randomized to usual care (n = 82), resistance exercise (RET, n = 82), or AET (n = 78) groups for the duration of their chemotherapy (median, 17 weeks). Supervised exercise was thrice weekly based on standard AET and RET prescriptions. Aerobic fitness (VO(2peak)) and Hb concentration were measured at baseline and end of chemotherapy. RESULTS: Regardless of the exercise group, Hb declined over the course of chemotherapy (13.4 ± 10.0 to 11.8 ± 11.5 g/dL, P < 0.01). Both AET and RET groups had significant, moderate correlations between the change in VO(2peak) and Hb (AET: r = 0.49, P < 0.001; RET: r = 0.39, P = 0.001). CONCLUSION: The results indicate that regular exercise does not protect against the decline in Hb associated with chemotherapy in breast cancer patients, but resulted in a stronger association between Hb and VO(2peak). IMPACT: Even with the chemotherapy-induced decline in Hb, breast cancer patients can maintain their aerobic capacity by participating in regular aerobic exercise. Further studies are required to determine safe intensity levels that may stimulate the maintenance of Hb levels in breast cancer patients.

Is there enhanced lymphatic function in upper body trained females?

BACKGROUND: Chronic physical activity results in adaptations in many aspects of human physiology, while specific training can directly influence structural changes. It remains unknown if habitual exercise influences upper extremity lymphatic function in females; thus, the purpose of this cross-sectional study was to compare different exercise stresses on lymphatic function in ten upper body trained females with ten untrained females. METHODS AND RESULTS: Participants underwent a maximal upper body aerobic test on an arm crank ergometer before undergoing three randomly assigned lymphatic stress tests. Lymphoscintigraphy was used to quantify lymphatic function. (99m)Tc-antimony colloid was injected into the third web space of each hand, followed by 1 min spot views taken with a gamma-radiation camera. The maximal stress test required individuals to repeat their initial maximal exercise test. The subjects were then imaged every 10 min until 60 min were reached. The submaximal stress test involved arm cranking for 2.5 min at 0.6 W x kg(-1), followed by 2.5 min of rest, repeated for 60 min. The final stress test was a 60 min seated resting session. The clearance rate (CR) and axillary uptake (AX) were determined. Only AX post maximal exercise was significantly different between trained and untrained, p=0.009. All other measures of lymphatic function between groups were similar. CONCLUSION: This study demonstrates no significant difference in lymphatic function between upper body trained and untrained females.

Upper extremity lymphatic function at rest and during exercise in breast cancer survivors with and without lymphedema compared with healthy controls.

Lymphoscintigraphy was used to measure lymphatic function at rest and during exercise in breast cancer survivors with lymphedema (BCRL, n = 10), breast cancer survivors (BC, n = 10), and controls (Cont, n = 10). After injection of (99m)Tc-antimony colloid to the hands, subjects rested or performed 12 repeated sets of arm cranking for 2.5 min at 0.6 W/kg followed by 2.5 min of rest. One-minute spot views were taken with a gamma-radiation camera immediately postinjection and every 10 min over 60 min to calculate clearance rate. As well, an upper body scan was taken at 65 min postinjection to measure radiopharmaceutical uptake in the axilla (Ax) and forearm (Fore). All groups displayed similar increases in clearance rate with exercise (P = 0.000). Ax significantly increased with exercise in Cont only [Cont: (mean +/- SD) 4.9 +/- 2.6 vs. 7.9 +/- 4.2%, P = 0.000; BCRL: 1.4 +/- 1.2 vs. 1.7 +/- 2.1%, P = 0.531; BC: 3.9 +/- 3.4 vs. 5.2 +/- 3.2%, P = 0.130], whereas Fore, indicating dermal backflow, significantly increased in BCRL only (BCRL: 2.4 +/- 0.87 vs. 4.4 +/- 2.0%, P = 0.004; BC: 1.1 +/- 0.25 vs. 1.1 +/- 0.31%, P = 0.784; Cont: 0.93 +/- 0.26 vs. 1.0 +/- 0.20%, P = 0.296). The results indicate that, in women with BCRL, exercise causes radiopharmaceuticals to clear from the hand at the same rate as BC and Cont, but, instead of reaching the axilla, a greater amount of activity gets trapped in the dermis of the forearm. BC, meanwhile, have similar lymphatic function as Cont; however, there is a highly variable response that may suggest that some BC subjects may be at risk for developing lymphedema.

Lymphoscintigraphy to evaluate the effect of high versus low intensity upper body dynamic exercise on lymphatic function in healthy females.

BACKGROUND: Little is known about the acute effects of exercise on the lymphatic system. Thus, the purpose was to determine the effect of low versus high intensity upper body exercise on lymphatic function in healthy females. METHODS AND RESULTS: On separate days, eight females performed either HI: 12 repeated sets of arm cranking for 2.5 min at 0.6 W.kg-1, followed by 2.5 min of rest; or LO: 12 repeated sets of arm cranking for 2.5 min at 0.3 W.kg-1, followed by 2.5 min of rest. One min spot views were taken with a gamma-radiation camera immediately after injection of 99mTc-antimony colloid and every 10 min thereafter to measure the clearance rate (CR) from the first and fourth finger-web of each hand. Radiopharmaceutical uptake in the axillary regions (AX) at 65 min postinjection was also measured. Clearance from the injection sites was linear and expressed as a slope (% administered activity.min-1). HI resulted in significantly greater CR (-0.24%.min-1+/-0.06) than LO (-0.19%.min-1+/-0.05; p=0.003). A similar trend was seen in AX (HI: 6.3%+/-1.6, LO: 4.8%+/-1.1, p=0.004). CONCLUSIONS: The results indicate that an arm cranking protocol of higher intensity is more effective in promoting lymphatic clearance from the hand. Further, the high intensity protocol may be useful in the functional evaluation of the lymphatic system in breast cancer survivors and warrants further investigation.