Suzanne Broadbent

Interval training for patients with coronary artery disease : a systematic review

Interval training (IT) may induce physiological adaptations superior to those achieved with conventional moderate-intensity continuous training (MCT) in patients with coronary artery disease (CAD). Our objectives were (1) to systematically review studies which have prescribed IT in CAD, (2) to summarize the findings of this research including the safety and physiological benefits of IT, and (3) to identify areas for further investigation. A systematic review of the literature using computerized databases was performed. The search yielded two controlled trials and five randomized controlled trials (RCTs) enrolling 213 participants. IT prescribed in isolation or in combination with resistance training was shown to induce significant and clinically important physiological adaptations in cardiac patients. IT was also shown to improve cardiorespiratory fitness (e.g. VO2max, VO2AT), endothelial function, left ventricle morphology and function (e.g. ejection fraction) to a significantly greater extent when compared with conventional MCT. No adverse cardiac or other life-threatening events occurred secondary to exercise participation in these studies. However, these findings must be interpreted with caution, as methodological limitations were present in all trials reviewed. In conclusion, robustly designed RCTs with thorough and standardized reporting are required to determine the risk and benefits of IT in the broader cardiac patient population. Further research is required to determine optimal IT protocols for the use in cardiac rehabilitation programmes, potentially contributing to novel exercise prescription guidelines for this patient population.

Effect of graded fructose coingestion with maltodextrin on exogenous 14C-fructose and 13C-glucose oxidation efficiency and high-intensity cycling performance

The ingestion of solutions containing carbohydrates with different intestinal transport mechanisms (e.g., fructose and glucose) produce greater carbohydrate and water absorption compared with single-carbohydrate solutions. However, the fructose-ingestion rate that results in the most efficient use of exogenous carbohydrate when glucose is ingested below absorption-oxidation saturation rates is unknown. Ten cyclists rode 2 h at 50% of peak power then performed 10 maximal sprints while ingesting solutions containing (13)C-maltodextrin at 0.6 g/min combined with (14)C-fructose at 0.0 (No-Fructose), 0.3 (Low-Fructose), 0.5 (Medium-Fructose), or 0.7 (High-Fructose) g/min, giving fructose:maltodextrin ratios of 0.5, 0. 8, and 1.2. Mean (percent coefficient of variation) exogenous-fructose oxidation rates during the 2-h rides were 0.18 (19), 0.27 (27), 0.36 (27) g/min in Low-Fructose, Medium-Fructose, and High-Fructose, respectively, with oxidation efficiencies (=oxidation/ingestion rate) of 62-52%. Exogenous-glucose oxidation was highest in Medium-Fructose at 0.57 (28) g/min (98% efficiency) compared with 0.54 (28), 0.48 (29), and 0.49 (19) in Low-Fructose, High-Fructose, No-Fructose, respectively; relative to No-Fructose, only the substantial 16% increase (95% confidence limits +/-16%) in Medium-Fructose was clear. Total exogenous-carbohydrate oxidation was highest in Medium-Fructose at 0.84 (26) g/min. Although the effect of fructose quantity on overall sprint power was unclear, the metabolic responses were associated with lower perceptions of muscle tiredness and physical exertion, and attenuated fatigue (power slope) in the Medium-Fructose and High-Fructose conditions. With the present solutions, low-medium fructose-ingestion rates produced the most efficient use of exogenous carbohydrate, but fatigue and the perception of exercise stress and nausea are reduced with moderate-high fructose doses.

Vibration therapy reduces plasma IL6 and muscle soreness after downhill running

Objective In this study, the effects of vibration therapy (VT) on delayed-onset muscle soreness (DOMS) and associated inflammatory markers after downhill running were determined. Methods 29 male recreational runners (33 (8) years; Vo2peak 57 (6) ml kg−1 min−1) completed a 40-min downhill run and were randomly allocated to a VT group or Control group. For 5 days post-run, the VT group underwent once-daily sessions of VT on the upper and lower legs. DOMS was assessed pre-run and for 5 days post-run by visual analogue scale. Immune cell subsets and plasma inflammatory markers were assessed pre-run, post-run, 24 and 120 h post-run by full differential cell count, and by ELISA and enzyme immunoassay, respectively. Data were analysed as per cent change from pre-run (ANOVA) and the magnitude of the treatment effect (Cohens effect size statistics). Results VT significantly reduced calf pain 96 h post-run (−50% (40%), 90% confidence limits) and gluteal pain 96 h (−50% (40%)) and 120 h post-run (−30% (30%)); decreased interleukin 6 (IL6) 24 h (−46% (31%)) and 120 h post-run (−65% (30%)); substantially decreased histamine 24 h (−40% (50%)) and 120 h post-run (−37% (48%)); substantially increased neutrophils (8.6% (8.1%)) and significantly decreased lymphocytes (−17% (12%)) 24 h post-run. There were no clear substantial effects of VT on other leukocyte subsets and inflammatory markers. Conclusion VT reduces muscle soreness and IL6. It may stimulate lymphocyte and neutrophil responses and may be a useful modality in treating muscle inflammation.

A protein-leucine supplement increases branched-chain amino acid and nitrogen turnover but not performance

PURPOSE This study aimed to determine the effect of postexercise protein-leucine coingestion with CHO-lipid on subsequent high-intensity endurance performance and to investigate candidate mechanisms using stable isotope methods and metabolomics. METHODS In this double-blind, randomized, crossover study, 12 male cyclists ingested a leucine/protein/CHO/fat supplement (LEUPRO 7.5/20/89/22 g · h(-1), respectively) or isocaloric CHO/fat control (119/22 g · h(-1)) 1-3 h after exercise during a 6-d training block (intense intervals, recovery, repeated-sprint performance rides). Daily protein intake was clamped at 1.9 g · kg(-1) · d(-1) (LEUPRO) and 1.5 g · kg(-1) · d(-1) (control). Stable isotope infusions (1-(13)C-leucine and 6,6-(2)H2-glucose), mass spectrometry-based metabolomics, and nitrogen balance methods were used to determine the effects of LEUPRO on whole-body branched-chain amino acid (BCAA) and glucose metabolism and protein turnover. RESULTS After exercise, LEUPRO increased BCAA levels in plasma (2.6-fold; 90% confidence limits = ×/÷ 1.1) and urine (2.8-fold; ×/÷ 1.2) and increased products of BCAA metabolism plasma acylcarnitine C5 (3.0-fold; ×/÷ 0.9) and urinary leucine (3.6-fold; ×/÷ 1.3) and β-aminoisobutyrate (3.4-fold; ×/÷ 1.4), indicating that ingesting ~10 g leucine per hour during recovery exceeds the capacity to metabolize BCAA. Furthermore, LEUPRO increased leucine oxidation (5.6-fold; ×/÷ 1.1) and nonoxidative disposal (4.8-fold; ×/÷ 1.1) and left leucine balance positive relative to control. With the exception of day 1 (LEUPRO = 17 ± 20 mg N · kg(-1), control = -90 ± 44 mg N · kg(-1)), subsequent (days 2-5) nitrogen balance was positive for both conditions (LEUPRO = 130 ± 110 mg N · kg(-1), control = 111 ± 86 mg N · kg(-1)). Compared with control feeding, LEUPRO lowered the serum creatine kinase concentration by 21%-25% (90% confidence limits = ± 14%), but the effect on sprint power was trivial (day 4 = 0.4% ± 1.0%, day 6 = -0.3% ± 1.0%). CONCLUSIONS Postexercise protein-leucine supplementation saturates BCAA metabolism and attenuates tissue damage, but effects on subsequent intense endurance performance may be inconsequential under conditions of positive daily nitrogen balance.

Effects of a clinician referral and exercise program for men who have completed active treatment for prostate cancer: A multicenter cluster randomized controlled trial (ENGAGE)

BACKGROUND : The purpose of this study was to determine the efficacy of a clinician referral and exercise program in improving exercise levels and quality of life for men with prostate cancer. METHODS : This was a multicenter cluster randomized controlled trial in Melbourne, Australia comprising 15 clinicians: 8 clinicians were randomized to refer eligible participants (n = 54) to a 12-week exercise program comprising 2 supervised gym sessions and 1 home-based session per week, and 7 clinicians were randomized to follow usual care (n = 93). The primary outcome was self-reported physical activity; the secondary outcomes were quality of life, anxiety, and symptoms of depression. RESULTS : A significant intervention effect was observed for vigorous-intensity exercise (effect size: Cohens d, 0.46; 95% confidence interval [CI], 0.09-0.82; P = .010) but not for combined moderate and vigorous exercise levels (effect size: d, 0.08; 95% CI, −0.28 to 0.45; P = .48). Significant intervention effects were also observed for meeting exercise guidelines (≥150 min/wk; odds ratio, 3.9; 95% CI, 1.9-7.8; P = .002); positive intervention effects were observed in the intervention group for cognitive functioning (effect size: d, 0.34; 95% CI, −0.02 to 0.70; P = .06) and depression symptoms (effect size: d, −0.35; 95% CI, −0.71 to 0.02; P = .06). Eighty percent of participants reported that the clinicians referral influenced their decision to participate in the exercise program. CONCLUSIONS : The clinician referral and 12-week exercise program significantly improved vigorous exercise levels and had a positive impact on mental health outcomes for men living with prostate cancer. Further research is needed to determine the sustainability of the exercise program and its generalizability to other cancer populations.The purpose of this study was to determine the efficacy of a clinician referral and exercise program in improving exercise levels and quality of life for men with prostate cancer.

Efficacy of a referral and physical activity program for survivors of prostate cancer [ENGAGE]: Rationale and design for a cluster randomised controlled trial

AbstractBackgroundDespite evidence that physical activity improves the health and well-being of prostate cancer survivors, many men do not engage in sufficient levels of activity. The primary aim of this study (ENGAGE) is to determine the efficacy of a referral and physical activity program among survivors of prostate cancer, in terms of increasing participation in physical activity. Secondary aims are to determine the effects of the physical activity program on psychological well-being, quality of life and objective physical functioning. The influence of individual and environmental mediators on participation in physical activity will also be determined.Methods/DesignThis study is a cluster randomised controlled trial. Clinicians of prostate cancer survivors will be randomised into either the intervention or control condition. Clinicians in the intervention condition will refer eligible patients (n = 110) to participate in an exercise program, comprising 12 weeks of supervised exercise sessions and unsupervised physical activity. Clinicians allocated to the control condition will provide usual care to eligible patients (n = 110), which does not involve the recommendation of the physical activity program. Participants will be assessed at baseline, 12 weeks, 6 months, and 12 months on physical activity, quality of life, anxiety, depression, self-efficacy, outcome expectations, goals, and socio-structural factors.DiscussionThe findings of this study have implications for clinicians and patients with different cancer types or other chronic health conditions. It will contribute to our understanding on the potential impact of clinicians promoting physical activity to patients and the long term health benefits of participating in physical activity programs.Trial registrationAustralia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12610000609055 Deakin University Human Research Ethics Approval 2011-085

Predictors of adherence to a 12-week exercise program among men treated for prostate cancer: ENGAGE study

Understanding the factors that influence adherence to exercise programs is necessary to develop effective interventions for people with cancer. We examined the predictors of adherence to a supervised exercise program for participants in the ENGAGE study – a cluster randomized controlled trial that assessed the efficacy of a clinician‐referred 12‐week exercise program among men treated for prostate cancer. Demographic, clinical, behavioral, and psychosocial data from 52 participants in the intervention group were collected at baseline through self‐report and medical records. Adherence to the supervised exercise program was assessed through objective attendance records. Adherence to the supervised exercise program was 80.3%. In the univariate analyses, cancer‐specific quality of life subscales (role functioning r = 0.37, P = 0.01; sexual activity r = 0.26, P = 0.06; fatigue r = −0.26, P = 0.06, and hormonal symptoms r = −0.31, P = 0.03) and education (d = −0.60, P = 0.011) were associated with adherence. In the subsequent multivariate analysis, role functioning (B = 0.309, P = 0.019) and hormonal symptoms (B = −0.483, P = 0.054) independently predicted adherence. Men who experienced more severe hormonal symptoms had lower levels of adherence to the exercise program. Those who experienced more positive perceptions of their ability to perform daily tasks and leisure activities had higher levels of adherence to the exercise program. Hormonal symptoms and role functioning need to be considered when conducting exercise programs for men who have been treated for prostate cancer.

Graded versus Intermittent Exercise Effects on Lymphocytes in Chronic Fatigue Syndrome.

PURPOSE There is increasing evidence of immune system dysfunction in chronic fatigue syndrome (CFS), but little is known of the regular exercise effects on immune cell parameters. This pilot study investigated the effects of graded and intermittent exercise on CD4 lymphocyte subset counts and activation compared with usual care. METHODS Twenty-four CFS patients (50.2 ± 10 yr) were randomized to graded exercise (GE), intermittent exercise (IE), or usual care (UC) groups; 18 sedentary non-CFS participants (50.6 ± 10 yr) were controls (CTL) for blood and immunological comparisons. Outcome measures were pre- and postintervention flow cytometric analyses of circulating lymphocyte subset cell counts; expression of CD3, CD4, CD25, and CD134; full blood counts; and V˙O2peak. RESULTS Preintervention, CD3 cell counts, and expression of CD4, CD25, CD134, and CD4CD25CD134 were significantly lower in GE, IE, and UC compared with CTL (P < 0.05). Total lymphocyte concentration was significantly lower in GE and IE groups compared with CTL. There were significant postintervention increases in i) expression of CD4 and CD4CD25CD134 for GE and IE, but CD25 and CD134 for IE only; ii) circulating counts of CD3 and CD4 for GE, and CD3, CD4, CD8, CD3CD4CD8, CD3CD16CD56, CD19, and CD45 for IE; iii) neutrophil concentration for GE; and iv) V˙O2peak and elapsed test time for IE and GE, V˙Epeak for IE. CONCLUSIONS Twelve weeks of GE and IE training significantly improved CD4 lymphocyte activation and aerobic capacity without exacerbating CFS symptoms. IE may be a more effective exercise modality with regard to enhanced CD4 activation in CFS patients.

The protocol for a randomised controlled trial comparing intermittent and graded exercise to usual care for chronic fatigue syndrome patients

BackgroundChronic Fatigue Syndrome is a debilitating disorder with an unknown aetiology but suspected multifactorial origins. Common “triggers” include severe viral infections and emotional stress. Recent studies have also found evidence of immune dysfunction and elevated inflammatory cytokines in CFS patients, but there has been considerable variation in the outcome measures and magnitude of these studies. Currently, there is no cure for CFS but treatments include rest, specialist medical care, cognitive behavioural therapy, and graded (self-paced) exercise. To date, several studies have examined the efficacy of graded exercise with or without Cognitive Behavioural Therapy, with some success for patients. However, improvements in functional capacity have not necessarily correlated with improvements in immune function, fatigue or other symptoms. This 12-week pilot trial compares graded and intermittent exercise to normal care, measuring physiological outcomes, fatigue levels, immune function and wellness.Methods/design90 patients aged between 16 to 60 years, who meet the diagnostic criteria for CFS and have been diagnosed by their medical practitioner, will be randomly recruited into groups consisting of Intermittent exercise, Graded exercise and usual care (Control). The outcomes will be measured pre-study (Week 0) and post-study (Week 13). Primary outcomes are VO2peak, anaerobic threshold, peak power, levels of fatigue, immune cell (CD3+CD4+, CD3+CD8+, CD19+, CD 16+CD56+) concentrations and activation. Secondary outcomes include onset of secondary CFS symptoms (e.g. fever, swollen lymph nodes), wellness, mood and sleep patterns. Primary analysis will be based on intention to treat using logistic regression models to compare treatments. Quantitative data will be analysed using repeated measures ANOVA with a linear model, and Cohen’s effect size. Qualitative data such as participants’ responses (e.g. changes in mood and other reactions) following the exercise modalities will be read and sections demarcated. A code will be applied to each segment. A prevalence of codes will be considered thematically.DiscussionThe results of the trial will provide information about the efficacy of intermittent and graded exercise compared to usual care (rest and lifestyle recommendations), contributing to the evidence for best-practice CFS management.Trial registrationAustralia and New Zealand Clinical Trials Registry ACTRN12612001241820.

Intermittent and graded exercise effects on NK cell degranulation markers LAMP‐1/LAMP‐2 and CD8+CD38+ in chronic fatigue syndrome/myalgic encephalomyelitis

There is substantial evidence of immune system dysfunction in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) but little is understood of exercise training effects on lymphocyte function in this illness. This study investigated whether graded and intermittent exercise improved CD8+ lymphocyte activation and natural killer cell degranulation markers compared to no exercise. Twenty‐four chronic fatigue syndrome (CFS) patients (50.2 ± 10 year) were randomized to graded exercise (GE), intermittent exercise (IE) or usual care (UC) groups; a control group (CTL) of 18 matched sedentary non‐CFS/ME participants were included for immunological variable comparisons. Main outcome measures were pre‐ and postintervention expression of CD3+CD8+CD38+ and CD3−CD16+56+CD107a+ (LAMP‐1) CD107b+ (LAMP‐2) and aerobic exercise capacity. The postintervention percentage of NK cells expressing LAMP‐1 and ‐2 was significantly higher in IE compared to UC, and higher in GE compared to UC and CTL. LAMP‐1 and LAMP‐2 expression (absolute numbers and percent positive) increased significantly pre‐to‐postintervention for both GE and IE. Preintervention, the absolute number of CD8+CD38+ cells was significantly lower in CTL compared to UC and IE. There were no significant pre‐ to postintervention changes in CD8+CD38+ expression for any group. Aerobic exercise capacity was significantly improved by GE and IE. Twelve weeks of GE and IE increased the expression of NK cell activation and degranulation markers, suggesting enhanced immunosurveillance. Low‐intensity exercise may also reduce CD8+CD38+ expression, a marker of inflammation. Both GE and IE improved exercise capacity without worsening CFS/ME symptoms, and more robust trials of these exercise modalities are warranted.