Associations between health-related fitness and patient-reported symptoms in newly diagnosed breast cancer patients.

BACKGROUND: Newly diagnosed breast cancer patients experience symptoms that may affect their quality of life, treatment outcomes, and survival. Preventing and managing breast cancer-related symptoms soon after diagnosis is essential. The purpose of this study was to investigate the associations between health-related fitness (HRF) and patient-reported symptoms in newly diagnosed breast cancer patients. METHODS: This study utilized baseline data from the Alberta Moving Beyond Breast Cancer Cohort Study that were collected within 90 days of diagnosis. HRF measures included peak cardiopulmonary fitness (peak volume of oxygen consumption [VO2peak]), maximal muscular strength and endurance, flexibility, and body composition. Symptom measures included depression, sleep quality, and fatigue. Adjusted multivariable logistic regression was performed for analyses. RESULTS: Of 1458 participants, 51.5% reported poor sleep quality, 26.5% reported significant fatigue, and 10.4% reported moderate depression. In multivariable-adjusted models, lower relative VO2peak was independently associated with a greater likelihood of all symptom measures, including moderate depression (p < 0.001), poor sleep quality (p = 0.009), significant fatigue (p = 0.008), any symptom (p < 0.001), and multiple symptoms (p < 0.001). VO2peak demonstrated threshold associations with all symptom measures such that all 3 lower quartiles exhibited similar elevated risk compared to the highest quartile. The strength of the threshold associations varied by the symptom measure with odds ratios ranging from ∼1.5 for poor sleep quality to ∼3.0 for moderate depression and multiple symptoms. Moreover, lower relative upper body muscular endurance was also independently associated with fatigue in a dose-response manner (p = 0.001), and higher body weight was independently associated with poor sleep quality in an inverted U pattern (p = 0.021). CONCLUSION: Relative VO2peak appears to be a critical HRF component associated with multiple patient-reported symptoms in newly diagnosed breast cancer patients. Other HRF parameters may also be important for specific symptoms. Exercise interventions targeting different HRF components may help newly diagnosed breast cancer patients manage specific symptoms and improve outcomes.

Social-cognitive, demographic, clinical, and health-related correlates of physical activity and sedentary behaviour in newly diagnosed women with breast cancer.

PURPOSE: Identifying correlates of physical activity and sedentary behaviour allows for the identification of factors that may be targeted in future behaviour change interventions. This study sought to determine the social-cognitive, demographic, clinical, and health-related correlates of physical activity and sedentary behaviour in individuals recently diagnosed with breast cancer. METHODS: Data were collected from 1381 participants within 90 days of diagnosis in the Alberta Moving Beyond Breast Cancer (AMBER) Cohort Study. Physical activity and sedentary behaviour were measured with ActiGraph GT3X+® and activPALTM devices, respectively, for seven consecutive days. Correlates were collected via a self-reported questionnaire, medical record extraction, or measured by staff. RESULTS: Multivariable models were fitted for sedentary behaviour, light physical activity, and moderate-to-vigorous physical activity. Greater sedentary behaviour was associated with higher body fat percentage (BF%) (ß=0.044; p<0.001) and being single (ß=0.542; p<0.002). Lower light physical activity was associated with higher BF% (ß=-0.044; p<0.001), higher body mass index (ß=-0.039; p<0.001), greater disease barrier influence (ß=-0.006; p<0.001), a HER2-positive diagnosis (ß=-0.278; p=0.001), and being single (ß=-0.385; p= 0.001). Lower moderate-to-vigorous physical activity was associated with higher BF% (ß =-0.011; p=0.001), greater disease barrier influence (ß=-0.002; p<0.001), and being of Asian (ß=-0.189; p=0.002) or Indian/South American (ß=-0.189; p=0.002) descent. Greater moderate-to-vigorous physical activity was associated with having greater intentions (ß=0.049; p=0.033) and planning (ß=0.026; p=0.015) towards physical activity. CONCLUSION: Tailoring interventions to increase physical activity for individuals recently diagnosed with breast cancer may improve long-term outcomes across the breast cancer continuum.

Depression, happiness, and satisfaction with life in women newly diagnosed with breast cancer: Associations with device-measured physical activity and sedentary time.

BACKGROUND: Few studies have examined depression after a cancer diagnosis and before initiating adjuvant or neoadjuvant systemic treatments. In this study, we present baseline data on device-measured physical activity, sedentary behaviour, depression, happiness, and satisfaction with life in newly diagnosed breast cancer survivors. PURPOSE: To examine associations of accelerometer-assessed physical activity and sedentary time with depression symptoms and prevalence, happiness, and satisfaction with life. METHODS: Shortly after diagnosis, 1425 participants completed depression, happiness, and satisfaction with life measures and wore an ActiGraph® device on their hip to measure physical activity and the activPALTM inclinometer on their thigh for 7 days to measure sedentary time (sitting/lying) and steps (1384 completed both device measures). ActiGraph® data were analysed using a hybrid machine learning method (R Sojourn package, Soj3x), and activPALTM data using activPALTM algorithms (PAL Software version 8). We used linear and logistic regression to examine associations of physical activity and sedentary time with depression symptom severity (0-27) and depression prevalence, happiness (0-100), and satisfaction with life (0-35). For the logistic regression analysis, we compared participants with none-minimal depression (n = 895) to participants with some depression (that is, mild, moderate, moderately-severe, or severe depression [n = 530]). RESULTS: Participants reported a mean depression symptom severity score of 4.3 (SD = 4.1), a satisfaction with life score of 25.7 (SD = 7.2), and a happiness score of 70 (SD = 21.8). Higher moderate-to-vigorous physical activity (MVPA) was associated with reduced depression symptom severity scores (ß = -0.51, 95% CI: -0.87 to -0.14, p = 0.007). A 1 hour increase in MVPA was associated with a reduced odds of at least mild or worse depression by 24% (Odds Ratio [OR] = 0.76, 95% CI: 0.62-0.94, p = 0.012). Higher daily step counts were associated with lower depression symptom severity scores (ß = -0.16, 95% CI: -0.24 to -0.10, p < 0.001). Perceptions of happiness was associated with higher MVPA (ß = 2.17, 95% CI: 0.17-4.17, p = 0.033). Sedentary time was not associated with depression severity, but higher sedentary time was associated with lower perceptions of happiness (ß = -0.80, 95% CI: -1.48 to -0.11, p = 0.023). CONCLUSIONS: Higher physical activity was associated with fewer depression symptom severity scores and reduced odds of mild or worse depression in women newly diagnosed with breast cancer. Higher physical activity and daily step counts were also associated with stronger perceptions of happiness and satisfaction with life, respectively. Sedentary time was not associated with depression symptom severity or odds of having depression, but was associated with stronger perceptions of happiness.

Associations between health-related fitness and quality of life in newly diagnosed breast cancer patients.

PURPOSE: Newly diagnosed breast cancer patients face substantial stress and uncertainty that may undermine their quality of life (QoL). The purpose of the present study was to examine the associations between health-related fitness (HRF) and QoL in newly diagnosed breast cancer patients from the Alberta Moving Beyond Breast Cancer Study. METHODS: Newly diagnosed breast cancer patients with early-stage disease (n = 1458) were recruited between 2012 and 2019 in Edmonton and Calgary, Canada to complete baseline HRF and QoL assessments within 90 days of diagnosis. HRF assessments included cardiorespiratory fitness (VO2peak treadmill test), muscular fitness (upper and lower body strength and endurance tests), and body composition (dual x-ray absorptiometry). QoL was assessed by the Medical Outcomes Study Short Form 36 (SF-36) version 2. We used logistic regression analyses to examine the associations between quartiles of HRF and poor/fair QoL (bottom 20%) after adjusting for key covariates. RESULTS: In multivariable analysis, the least fit groups compared to the most fit groups for relative upper body strength (OR = 3.19; 95% CI = 1.98-5.14), lean mass percentage (OR = 2.31; 95% CI = 1.37-3.89), and relative VO2peak (OR = 2.08; 95% CI = 1.21-3.57) were independently at a significantly higher risk of poor/fair physical QoL. No meaningful associations were found for mental QoL. CONCLUSIONS: The three main components of HRF (muscular fitness, cardiorespiratory fitness, and body composition) were independently associated with physical QoL in newly diagnosed breast cancer patients. Exercise interventions designed to improve these components of HRF may optimize physical QoL and help newly diagnosed breast cancer patients better prepare for treatments and recovery.

Associations of device-measured physical activity and sedentary time with quality of life and fatigue in newly diagnosed breast cancer patients: Baseline results from the AMBER cohort study.

BACKGROUND: This study examined associations of device-measured physical activity and sedentary time with quality of life (QOL) and fatigue in newly diagnosed breast cancer patients in the Alberta Moving Beyond Breast Cancer (AMBER) cohort study. METHODS: After diagnosis, 1409 participants completed the SF-36 version 2 and the Fatigue Scale, wore an ActiGraph device on their right hip to measure physical activity, and an activPAL device on their thigh to measure sedentary time (sitting/lying) and steps. ActiGraph data was analyzed using a hybrid machine learning method (R Sojourn package, Soj3x) and activPAL data were analyzed using activPAL algorithms (PAL Software version 8). Quantile regression was used to examine cross-sectional associations of QOL and fatigue with steps, physical activity, and sedentary hours at the 25th, 50th, and 75th percentiles of the QOL and fatigue distributions. RESULTS: Total daily moderate and vigorous physical activity (MVPA) hours was positively associated with better physical QOL at the 25th (ß = 2.14, p = <.001), 50th (ß = 1.98, p = <.001), and 75th percentiles (ß = 1.25, p = .003); better mental QOL at the 25th (ß = 1.73, p = .05) and 50th percentiles (ß = 1.07, p = .03); and less fatigue at the 25th (ß = 4.44, p < .001), 50th (ß = 3.08, p = <.001), and 75th percentiles (ß = 1.51, p = <.001). Similar patterns of associations were observed for daily steps. Total sedentary hours was associated with worse fatigue at the 25th (ß = -0.58, p = .05), 50th (ß = -0.39, p = .06), and 75th percentiles (ß = -0.24, p = .02). Sedentary hours were not associated with physical or mental QOL. CONCLUSIONS: MVPA and steps were associated with better physical and mental QOL and less fatigue in newly diagnosed breast cancer patients. Higher sedentary time was associated with greater fatigue symptoms.

The Alberta moving beyond breast cancer (AMBER) cohort study: baseline description of the full cohort.

PURPOSE: The Alberta Moving Beyond Breast Cancer (AMBER) Study is an ongoing prospective cohort study investigating how direct measures of physical activity (PA), sedentary behavior (SB), and health-related fitness (HRF) are associated with survival after breast cancer. METHODS: Women in Alberta with newly diagnosed stage I (≥ T1c) to IIIc breast cancer were recruited between 2012 and 2019. Baseline assessments were completed within 90 days of surgery. Measurements included accelerometers to measure PA and SB; a graded treadmill test with gas exchange analysis to measure cardiorespiratory fitness (VO2peak); upper and lower body muscular strength and endurance; dual-X-ray absorptiometry to measure body composition; and questionnaires to measure self-reported PA and SB. RESULTS: At baseline, the 1528 participants' mean age was 56 ± 11 years, 59% were post-menopausal, 62% had overweight/obesity, and 55% were diagnosed with stage II or III disease. Based on device measurements, study participants spent 8.9 ± 1.7 h/day sedentary, 4.4 ± 1.2 h/day in light-intensity activity, 0.9 ± 0.5 h/day in moderate-intensity activity, and 0.2 ± 0.2 h/day in vigorous-intensity activity. For those participants who reached VO2peak, the average aerobic fitness level was 26.6 ± 6 ml/kg/min. Average body fat was 43 ± 7.1%. CONCLUSION: We have established a unique cohort of breast cancer survivors with a wealth of data on PA, SB, and HRF obtained through both direct and self-reported measurements. Study participants are being followed for at least ten years to assess all outcomes after breast cancer. These data will inform clinical and public health guidelines on PA, SB, and HRF for improving breast cancer outcomes.

Whey protein isolate or concentrate combined with concurrent training does not augment performance, cardiorespiratory fitness, or strength adaptations.

BACKGROUND: Protein supplementation alters both strength and endurance training adaptations individually; however less is known regarding protein supplementation during concurrent training. The primary purpose of this study was to investigate the effects of whey protein supplementation during six weeks of concurrent training on performance, cardiorespiratory fitness, and maximal strength adaptations, as well as acute hormonal and immune responses. A secondary purpose was to explore the effects of two types of whey protein powders on these latter variables. METHODS: Thirty-one participants were randomly assigned to supplement with a placebo (PLA; N.=10), whey protein isolate (WPI; N.=10), or whey protein concentrate (WPC; N.=11) in addition to their habitual diet. Total protein intake was 1.2, 3.5, and 3.5 g/kg/day for PLA, WPI, WPC groups, respectively. Exercise testing was performed before and after 6 weeks of concurrent training. Blood samples were obtained at rest, and 5 and 60 minutes after a simulated 2000 m rowing race prior to and after training. RESULTS: There were similar but significant improvements in cardiorespiratory fitness (PLA +7.5%; WPI +3.9%; WPC +6.9%), upper body strength (PLA +5.5%; WPI +5.1%; WPC +6.7%), lower body strength (PLA +13.6%; WPI +9.4%; WPC +14.1%) and 2000m rowing performance (PLA -2.5%; WPI -2.3%; WPC -2.3%) in all groups, P<0.05. As well, hormonal and immune responses to acute exercise were similar over time and between groups. CONCLUSIONS: Whey protein supplementation did not differentially influence performance, cardiorespiratory fitness, upper and lower body strength, immune or hormonal adaptations following 6 weeks of concurrent training.

Whey Protein Isolate Supplementation While Endurance Training Does Not Alter Cycling Performance or Immune Responses at Rest or After Exercise.

This study examined whey protein isolate supplementation combined with endurance training on cycling performance, aerobic fitness and immune cell responses. Eighteen male cyclists were randomly assigned to either placebo (PLA) or whey protein supplementation (WS; 1.0 g·kg body mass-1·d-1 in addition to their dietary intake). Both groups completed the identical endurance training program, 4 days per week for 6 weeks. Blood samples were obtained at rest and after 5 and 60 min of recovery from a simulated 40 km cycling time trial (TT) and were repeated after training. Baseline dietary intake of protein prior to supplementation was 1.52 ± 0.45 and 1.46 ± 0.44 g·kg body mass-1·d-1 for the WS and PLA groups, respectively. There were similar improvements in TT performance (WS: 71.47 ± 12.17 to 64.38 ± 8.09 min; PLA: 72.33 ± 12.79 to 61.13 ± 8.97 min), and peak oxygen uptake (WS: 52.3 ± 6.1 to 56.1 ± 5.4 mL·kg-1·min-1; PLA: 50.0 ± 7.1 to 54.9 ± 5.1 mL·kg-1·min-1) after training in both groups. White blood cells (WBC) and neutrophil counts were elevated 5 min after the TT and further increased after 60 min (P < 0.05). The exercise-induced increase in WBC and neutrophil counts at 5 and 60 min after the TT were attenuated after training compared to before training (P < 0.05). Lymphocytes increased 5 min after the TT and decreased below rest after 60 min of recovery (P < 0.05). Following training lymphocytes were lower after 60 min of recovery compared to before training. There was no change in natural killer cell activity with exercise, training or between groups. It was concluded that whey protein isolate supplementation while endurance training did not differentially change cycling performance or the immune response at rest or after exercise. However, endurance training did alter performance, aerobic fitness and some post exercise immune cell counts.

Glycemic and Metabolic Effects of Two Long Bouts of Moderate-Intensity Exercise in Men with Normal Glucose Tolerance or Type 2 Diabetes.

BACKGROUND: The glycemic and insulinemic responses following 30-60 min of exercise have been extensively studied, and a dose-response has been proposed between exercise duration, or volume, and improvements in glucose tolerance or insulin sensitivity. However, few studies have examined the effects of longer bouts of exercise in type 2 diabetes (T2D). Longer bouts may have a greater potential to affect glucagon, interleukin-6 (IL-6) and incretin hormones [i.e., glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP)]. AIM: To examine the effect of two bouts of long-duration, moderate-intensity exercise on incretins, glucagon, and IL-6 responses before and after exercise, as well as in response to an oral glucose tolerance test (OGTT) conducted the following day. METHODS: Twelve men, six with and six without T2D, participated in two separate conditions (i.e., exercise vs. rest) according to a randomized crossover design. On day 1, participants either rested or performed two 90 min bouts of treadmill exercise (separated by 3.5 h) at 80% of their ventilatory threshold. All participants received standardized meals on day 1. On day 2 of each condition, glucose and hormonal responses were measured during a 4-h OGTT. RESULTS: On day 1, exercise increased IL-6 at the end of the first bout of exercise (exercise by time interaction p = 0.03) and GIP overall (main effect of exercise p = 0.004). Glucose was reduced to a greater extent in T2D following exercise (exercise by T2D interaction p = 0.03). On day 2, GIP and active GLP-1 were increased in the fasting state (p = 0.05 and p = 0.03, respectively), while plasma insulin and glucagon concentrations were reduced during the OGTT (p = 0.01 and p = 0.02, respectively) in the exercise compared to the rest condition for both healthy controls and T2D. Postprandial glucose was elevated in T2D compared to healthy control (p < 0.05) but was not affected by exercise. CONCLUSION: Long-duration, moderate-intensity aerobic exercise can increase IL-6. On the day following exercise, fasting incretins remained increased but postprandial insulin and glucagon were decreased without affecting postprandial glucose. This long duration of exercise may not be appropriate for some people, and further research should investigate why next day glucose tolerance was unchanged.

A Pilot Randomized, Controlled Trial of a Wall Climbing Intervention for Gynecologic Cancer Survivors.

PURPOSE/OBJECTIVES: To examine the feasibility and preliminary efficacy of an eight-week supervised climbing intervention for gynecologic cancer survivors (GCSs).
. DESIGN: A pilot randomized, controlled trial.
. SETTING: The Wilson Climbing Center in Edmonton, Alberta, Canada.
. SAMPLE: 35 GCSs who had completed cancer therapy.
. METHODS: GCSs were randomized to an eight-week (16 session) supervised wall climbing intervention (WCI) (n = 24) or usual care (UC) (n = 11).
. MAIN RESEARCH VARIABLES: Feasibility outcomes included recruitment rate, adherence rate, skill performance, and safety. Preliminary efficacy outcomes were objective health-related and functional fitness assessed before and after the eight-week intervention using the Senior Fitness Test.
. FINDINGS: Median adherence to the WCI was 13.5 of 16 sessions. Most GCSs were proficient on 16 of 24 skill assessment items. No serious adverse events were reported. Based on intention-to-treat analyses, the WCI group was superior to the UC group for the 6-minute walk, 30-second chair stand, 30-second arm curls, sit and reach, 8-foot up-and-go, grip strength-right, and grip strength-left assessments.
. CONCLUSIONS: The Gynecologic Cancer Survivors Wall Climbing for Total Health (GROWTH) Trial demonstrated that an eight-week supervised WCI was safe, feasible, and improved functional fitness in GCSs. Phase II and III trials are warranted to further establish the safety, feasibility, and efficacy of WCIs in cancer survivors.
. IMPLICATIONS FOR NURSING: Oncology nurses may consider a climbing wall as an alternative type of physical activity for improving functional fitness in GCSs.

The Alberta Moving Beyond Breast Cancer (AMBER) Cohort Study: Recruitment, Baseline Assessment, and Description of the First 500 Participants.

BACKGROUND: To our knowledge, the Alberta Moving Beyond Breast Cancer (AMBER) Study is the first and only prospective cohort study of breast cancer survivors that includes objectively-measured physical activity (PA), sedentary behavior, health-related fitness (HRF), and biologic mechanisms focused on understanding breast cancer outcomes. The purpose of the present study was to report on the feasibility of recruitment, baseline measurement completion, and the representativeness of the first 500 participants. METHODS: AMBER is enrolling newly diagnosed stage I (≥T1c) to IIIc breast cancer survivors in Alberta, Canada. Baseline assessments are completed soon after diagnosis and include cardiorespiratory fitness, musculoskeletal fitness, body composition, objective and self-reported PA and sedentary behavior, lymphedema, and blood collection. RESULTS: Between July 2012 and November 2014, AMBER recruited its first 500 participants from a pool of 1,447 (35 %) eligible breast cancer survivors. Baseline HRF assessments were completed on ≥85 % of participants with the exception of upper body strength. Collection of ≥4 days/week of monitoring for the Actigraph GT3X® and ActivPAL® were obtained from 90 % of participants. Completion rates were also high for blood (99 %), lymphedema (98 %), and questionnaires (95 %) including patient-reported outcomes and correlates of exercise. The first 500 participants in AMBER are an average age of 56 years, 60 % are overweight or obese, and 58 % have disease stage II or III. CONCLUSION: Despite the modest recruitment rate and younger age, AMBER has demonstrated that many newly diagnosed breast cancer survivors are willing and able to complete a wide array of sophisticated and physically demanding HRF and PA assessments soon after diagnosis. AMBER is a unique breast cancer survivor cohort that may inform future randomized controlled trials on lifestyle and breast cancer outcomes as well as PA behavior change in breast cancer survivors. Moreover, AMBER may also inform guidelines on PA, sedentary behavior, and HRF for improving breast cancer outcomes and survivorship.

Targeting specific interstitial glycemic parameters with high-intensity interval exercise and fasted-state exercise in type 2 diabetes.

AIMS: To compare the acute glycemic responses to a bout of high-intensity interval exercise (HIIE) and energy-matched moderate-intensity continuous exercise (MICE) performed under fasted and postprandial conditions. METHODS: A randomized, controlled, crossover design was used. Ten individuals with type 2 diabetes were each tested in five experimental conditions after an overnight fast: 1) fasted-state HIIE (HIIEfast); 2) post-breakfast HIIE (HIIEfed); 3) fasted-state MICE (MICEfast); 4) post-breakfast MICE (MICEfed); and 5) no exercise (control). MICE was performed at workload corresponding to 55% of V.V̇O2peak, whereas HIIE was composed of repetitions of three minutes at workload corresponding to 40% followed by one minute at workload corresponding to 100% V.V̇̇O2peak. Interstitial glucose was monitored by continuous glucose monitoring over 24h under standardized diet and medication. RESULTS: Fasted-state exercise attenuated postprandial glycemic increments (p<0.05) to a greater extent than post-breakfast exercise did. HIIE reduced nocturnal and fasting glycemia on the day following exercise more than MICE did (main effect: both p<0.05). Compared to the control condition, HIIEfast lowered most interstitial glycemic parameters, i.e., 24-h mean glucose (-1.5mmol·l(-1); p<0.05), fasting glucose (-1.0mmol·l(-1); p<0.05), overall postprandial glycemic increment (-257mmol·360min·l(-1); p<0.05), glycemic variability (-1.79mmol·l(-1); p<0.05), and time spent in hyperglycemia (-283min; p<0.05). CONCLUSION: This study showed that HIIE is more effective than MICE in lowering nocturnal/fasting glycemia. Exercise performed in the fasted state reduces postprandial glycemic increments to a greater extent than post-breakfast exercise does. Performing HIIE under fasted condition may be most advantageous as it lowered most aspects of glycemia.

Feasibility and efficacy of a 12-week supervised exercise intervention for colorectal cancer survivors.

Exercise training improves health-related physical fitness and patient-reported outcomes in cancer survivors, but few interventions have targeted colorectal cancer (CRC) survivors. This investigation aimed to determine the feasibility and efficacy of a 12-week supervised exercise training program for CRC survivors. Feasibility was assessed by tracking participant recruitment, loss to follow-up, assessment completion rates, participant evaluation, and adherence to the intervention. Efficacy was determined by changes in health-related physical fitness. Over a 1-year period, 72 of 351 (21%) CRC survivors screened were eligible for the study and 29 of the 72 (40%) were enrolled. Two participants were lost to follow-up (7%) and the completion rate for all study assessments was ≥93%. Mean adherence to the exercise intervention was 91% (standard deviation = ±18%), with a median of 98%. Participants rated the intervention positively (all items ≥ 6.6/7) and burden of testing low (all tests ≤ 2.4/7). Compared with baseline, CRC survivors showed improvements in peak oxygen uptake (mean change (MC) = +0.24 L·min(-1), p < 0.001), upper (MC = +7.0 kg, p < 0.001) and lower (MC = +26.5 kg, p < 0.001) body strength, waist circumference (MC = -2.1 cm, p = 0.005), sum of skinfolds (MC = -7.9 mm, p = 0.006), and trunk forward flexion (MC = +2.5 cm, p = 0.019). Exercise training was found to be feasible and improved many aspects of health-related physical fitness in CRC survivors that may be associated with improved quality of life and survival in these individuals.

Test-retest reliability of a continuous glucose monitoring system in individuals with type 2 diabetes.

AIMS: This study determined the test-retest reliability of a continuous glucose monitoring system (CGMS) (iPro™2; Medtronic, Northridge, CA) under standardized conditions in individuals with type 2 diabetes (T2D). SUBJECTS AND METHODS: Fourteen individuals with T2D spent two nonconsecutive days in a calorimetry unit. On both days, meals, medication, and exercise were standardized. Glucose concentrations were measured continuously by CGMS, from which daily mean glucose concentration (GLU(mean)), time spent in hyperglycemia (t(>10.0 mmol/L)), and meal, exercise, and nocturnal mean glucose concentrations, as well as glycemic variability (SD(w), percentage coefficient of variation [%cv(w)], mean amplitude of glycemic excursions [MAGEc, MAGE(ave), and MAGE(abs.gos)], and continuous overlapping net glycemic action [CONGA(n)]) were estimated. Absolute and relative reliabilities were investigated using coefficient of variation (CV) and intraclass correlation, respectively. RESULTS: Relative reliability ranged from 0.77 to 0.95 (P<0.05) for GLU(mean) and meal, exercise, and nocturnal glycemia with CV ranging from 3.9% to 11.7%. Despite significant relative reliability (R=0.93; P<0.01), t(>10.0 mmol/L) showed larger CV (54.7%). Among the different glycemic variability measures, a significant between-day difference was observed in MAGEc, MAGE(ave), CONGA6, and CONGA12. The remaining measures (i.e., SD(w), %cv(w), MAGE(abs.gos), and CONGA1-4) indicated no between-day differences and significant relative reliability. CONCLUSIONS: In individuals with T2D, CGMS-estimated glycemic profiles were characterized by high relative and absolute reliability for both daily and shorter-term measurements as represented by GLUmean and meal, exercise, and nocturnal glycemia. Among the different methods to calculate glycemic variability, our results showed SD(w), %cv(w), MAGE(abs.gos), and CONGAn with n ≤ 4 were reliable measures. These results suggest the usefulness of CGMS in clinical trials utilizing repeated measured.

Oral L-arginine before resistance exercise blunts growth hormone in strength trained males.

Acute resistance exercise and L-arginine have both been shown to independently elevate plasma growth hormone (GH) concentrations; however, their combined effect is controversial. The purpose was to investigate the combined effects of resistance exercise and L-arginine supplementation on plasma L-arginine, GH, GH secretagogues, and IGF-1 in strength trained participants. Fourteen strength trained males (age: 25 ± 4 y; body mass: 81.4 ± 9.0 kg; height: 179.4 ± 6.9 cm; and training experience: 6.3 ± 3.4 y) participated in a randomized double-blind crossover design (separated by ~7 days). Subjects reported to the laboratory at 08:00 in a fasted state, consumed L-arginine (ARG; 0.075 g·kg-1 body mass) or a placebo (PLA) before performing an acute bout of resistance exercise (3 sets of 8 exercises, 10 repetitions at ~75% 1RM). Blood samples were collected at rest, before exercise, and at 0, 15, 30, and 60 min of rest-recovery. The ARG condition significantly increased plasma L-arginine concentrations (~120%) while no change was detected in the PLA condition. There were no differences between conditions for GH, GH-releasing hormone, ghrelin, or IGF-1 at any time point. GH-inhibiting hormone was significantly lower in the ARG condition. However, integrated area under the curve for GH was blunted in the ARG condition (L-arginine = 288.4 ± 368.7 vs. placebo = 487.9± 482.0 min·ng·mL1, p < .05). L-arginine ingested before resistance exercise significantly elevated plasma L-arginine concentration but attenuated plasma GH in strength trained individuals despite a lower GHIH. Furthermore our data shows that the GH suppression was not due to a GH or IGF-1 induced autonegative feedback loop.

Dose response of whey protein isolate in addition to a typical mixed meal on blood amino acids and hormonal concentrations.

The purpose was to investigate the effects of a controlled typical 1-day diet supplemented with two different doses of whey protein isolate on blood amino acid profiles and hormonal concentrations following the final meal. Nine males (age: 29.6 ± 6.3 yrs) completed four conditions in random order: a control (C) condition of a typical mixed diet containing ~10% protein (0.8 g·kg1), 65% carbohydrate, and 25% fat; a placebo (P) condition calorically matched with carbohydrate to the whey protein conditions; a low-dose condition of 0.8 grams of whey protein isolate per kilogram body mass per day (g·kg1·d1; W1) in addition to the typical mixed diet; or a high-dose condition of 1.6 g·kg1·d1 (W2) of supplemental whey protein in addition to the typical mixed diet. Following the final meal, significant (p < .05) increases in total amino acids, essential amino acids (EAA), branch-chained amino acids (BCAA), and leucine were observed in plasma with whey protein supplementation while no changes were observed in the control and placebo conditions. There was no significant group difference for glucose, insulin, testosterone, cortisol, or growth hormone. In conclusion, supplementing a typical daily food intake consisting of 0.8 g of protein·kg1·d1 with a whey protein isolate (an additional 0.8 or 1.6 g·kg1·d1) significantly elevated total amino acids, EAA, BCAA, and leucine but had no effect on glucose, insulin, testosterone, cortisol, or growth hormone following the final meal. Future acute and chronic supplementation research examining the physiological and health outcomes associated with elevated amino acid profiles is warranted.

Effects of aerobic exercise with or without metformin on plasma incretins in type 2 diabetes.

OBJECTIVE: Despite positive effects of incretins on insulin secretion, little is known about the effect of exercise on these hormones. Metformin can affect incretin concentrations and is prescribed to a large proportion of people with diabetes. We, therefore, examined the effects of aerobic exercise and/or metformin on incretin hormones. METHODS: Ten participants with type 2 diabetes were recruited for this randomized crossover study. Metformin or placebo was given for 28 days, followed by the alternate treatment for 28 days. On the last 2 days of each condition, participants were assessed during a non-exercise day and a subsequent exercise day. Aerobic exercise took place in the morning and blood samples were taken in the subsequent hours (before and after lunch). RESULTS: Aerobic exercise did not increase total plasma glucagon-like peptide-1 (GLP-1) or glucose-dependent insulinotropic polypeptide (GIP) in the pre- or post-lunch periods (all p>0.1). GLP-1 was higher in the pre-lunch (p=0.016) and post-lunch (p=0.018) periods of the metformin conditions compared with the placebo. Total plasma GIP was higher in the pre-lunch period (p=0.05), but not in the post-lunch period (p=0.95), with metformin compared with placebo. CONCLUSIONS: In contrast to our hypothesis, aerobic exercise did not acutely increase total GLP-1 and GIP levels in patients with type 2 diabetes. Metformin, independent of exercise, significantly increased total plasma GLP-1 and GIP concentrations in these patients.

Exploring the variability in acute glycemic responses to exercise in type 2 diabetes.

AIM: To explore the factors associated with exercise-induced acute capillary glucose (CapBG) changes in individuals with type 2 diabetes (T2D). METHODS: Fifteen individuals with T2D were randomly assigned to energy-matched high intensity interval exercise (HI-IE) and moderate intensity continuous exercise (MI-CE) interventions and performed a designated exercise protocol 5 days per week for 12 weeks. The duration of exercise progressed from 30 to 60 minutes. CapBG was measured immediately before and after each exercise session. Timing of food and antihyperglycemic medication intake prior to exercise was recorded. RESULTS: Overall, the mean CapBG was lowered by 1.9 mmol/L (P < 0.001) with the change ranging from -8.9 to +2.7 mmol/L. Preexercise CapBG (44%; P < 0.001), medication (5%; P < 0.001), food intake (4%; P = 0.043), exercise duration (5%; P < 0.001), and exercise intensity (1%; P = 0.007) were all associated with CapBG changes, explaining 59% of the variability. CONCLUSION: The greater reduction in CapBG seen in individuals with higher preexercise CapBG may suggest the importance of exercise in the population with elevated glycemia. Lower blood glucose can be achieved with moderate intensity exercise, but prolonging exercise duration and/or including brief bouts of intense exercise accentuate the reduction, which can further be magnified by performing exercise after meals and antihyperglycemic medication. This trial is registered with ClinicalTrial.gov NCT01144078.

Inspiratory and expiratory respiratory muscle training as an adjunct to concurrent strength and endurance training provides no additional 2000 m performance benefits to rowers.

The purpose of this study was to examine respiratory muscle training (RMT) combined with 9 weeks of resistance and endurance training on rowing performance and cardiopulmonary responses. Twenty-seven rowers (mean ± SD: age = 27 ± 9 years; height = 176.9 ± 10.8 cm; and body mass = 76.1 ± 12.6 kg) were randomly assigned to an inspiratory only (n = 13) or expiratory only (n = 14) training group. Both RMT programs were 3 sets of 10 reps, 6 d/wk in addition to an identical 3 d/wk resistance and 3 d/wk endurance training program. Both groups showed similar improvements in 2000 m rowing performance, cardiorespiratory fitness, strength, and maximum inspiratory (PImax) and expiratory (PEmax) pressures (p < .05). It was concluded that there were no additional benefits of 9 weeks of inspiratory or expiratory RMT on simulated 2000 m rowing performance or cardiopulmonary responses when combined with resistance and endurance training in rowers.

Time-motion analysis, heart rate, and physiological characteristics of international canoe polo athletes.

To evaluate the time international canoe polo players spend performing various game activities, measure heart rate (HR) responses during games, and describe the physiological profile of elite players. Eight national canoe polo players were videotaped and wore HR monitors during 3 games at a World Championship and underwent fitness testing. The mean age, height, and weight were 25 ± 1 years, 1.82 ± 0.04 m, and 81.9 ± 10.9 kg, respectively. Time-motion analysis of 3 games indicated that the players spent 29 ± 3% of the game slow and moderate forward paddling, 28 ± 5% contesting, 27 ± 5% resting and gliding, 7 ± 1% turning, 5 ± 1% backward paddling, 2 ± 1% sprinting, and 2 ± 1% dribbling. Sixty-nine (±20)% of the game time was played at an HR intensity above the HR that corresponded to the ventilatory threshold (VT) that was determined during the peak V[Combining Dot Above]O2 test. Peak oxygen uptake and VT were 3.3 ± 0.3 and 2.2 ± 0.3 L·min, respectively, on a modified Monark arm crank ergometer. Arm crank peak 5-second anaerobic power was 379 W. The majority of the time spent during international canoe polo games involved slow-to-moderate forward paddling, contesting for the ball, and resting and gliding. Canoe polo games are played at a high intensity indicated by the HR responses, and the physiological characteristics suggest that these athletes had high levels of upper body aerobic and anaerobic fitness levels.