680 Energy expenditure (EE; Kcal·hr-1) was determined at five ratings of perceived exertion (RPE; Borg 15 pt. scale), during simulated cross-country skiing (S), rider (R), and rowing ergometer (RE) exercise. The three exercise machines were selected because they involved combined arm and leg exercise. Subjects (n=8 males, age 23.4 ± 1.2 yrs, treadmill VO2max 50.3 ± 1.5 ml·kg·min-1) performed a maximal exercise test to anchor the RPE scale. A mode specific discontinuous maximal test was undertaken during which subjects rated RPE for the overall body (RPE-O) at the end of each 2 minute stage. EE was estimated from VO2 (l·min-1) obtained for the last minute of each test stage and adjusted using RER. TableTableEE during exercise on the S was highest (p<0.05) at each RPE-O. EE on the RE was lower (p<0.05) than the S at RPEs 9, 11 and 13. EE was lower(p<0.05) on the R than the S at all RPEs. When prescribing exercise intensity for purpose of body weight management using a “target training” RPE-O between 9 and 17, the present findings suggest that the S provides a comparatively greater caloric demand than the other arm-leg modalities studied.
This investigation evaluated the effect of oral potassium phosphate supplementation on ratings of perceived exertion (RPE) and physiological responses during maximal graded exercise tests (GXT). Eight highly trained endurance runners completed a GXT to anchor the Borg 15-point RPE scale and two double-blind counterbalanced GXTs. Subjects ingested either 4,000 mg · day −1 of phosphate (PHOS) or a placebo (PLA) for 2 days. Two weeks separated GXTs. Phosphate levels obtained immediately prior to the GXTs were greater in PHOS than PLA. No differences between PHOS and PLA were noted for the submaximal and maximal physiological responses. RPE for the overall body were lower during PHOS than PLA at intensities corresponding to 70–80% of V̇O 2max . This suggests that oral potassium phosphate supplementation mediates perceived exertion during moderately intense exercise.
PURPOSE: Emerging data have revealed a negative association between insulin resistance (IR) and muscle function, however there is a lack of research to examine the independent influence of IR on adaptation to resistance exercise (RE). The purpose of this investigation was to examine the contribution of homeostasis model assessment of insulin resistance (HOMA-IR) on adaptive response to resistance exercise. METHODS: Analyses included 697 adults (281 males, 416 females; age = 23.7 ± 5.6 yrs). HOMA-IR, subcutaneous adipose tissue (SAT) and muscle mass (MRI-derived SAT and biceps muscle volume), and dynamic biceps strength (1 repetition maximum [1RM]) were analyzed at baseline and following 12-weeks of unilateral RE. Periodized RE incorporated dumbbell exercises for the non-dominant upper arm. Multivariate analysis was conducted to assess the adaptive-responses for outcomes following RE. In each of these models, post-intervention means were entered as the dependent variable, and baseline muscle characteristics were entered as covariates, along with the pre-specified significant correlates as independent moderators. This method was completed to reduce the risk of regression to the mean. RESULTS: Adaptation to RE revealed a significant negative association between HOMA-IR and changes for strength capacity (B = -0.05; p = 0.02), controlling for sex, age, body mass index, and SAT, as well as baseline muscle characteristics (i.e. muscle mass and strength) as covariates. Changes in muscle size after RE were not significantly associated with HOMA-IR. CONCLUSIONS: Findings reveal that insulin resistance is an independent negative predictor of strength adaptive-response among adults.
This study examined the effects of acute continuous incremental exercise on lymphocyte mitogenic function and cytokine production in physically active and sedentary males and females. Physically active (n = 32) and sedentary (N = 32) male and female subjects were randomly assigned to an exercise or control condition. Exercise involved a continuous incremental protocol consisting of cycling for 3 periods of 6 min at workrates corresponding to 55 %, 70 % and 85 % VO2peak. Blood samples were drawn from a venous catheter at baseline, 6min, 12 min and 18 min, and 2 h following completion of exercise. Relative to baseline and control condition the percentage of T (CD3+) and B cells (CD19+) significantly decreased, and the percentage of NK cells (CD3-CD16+CD56+) increased (p < 0.001) during each stage of the incremental exercise test. The proliferative response to ConA was suppressed, enhanced, or unchanged using 1.25 μg/ml, 2.5(μg/ml and 5.0 μg/ml ConA, respectively. The in-vitro production of IL-1 and IFN-γ increased during each workload. In contrast IL-4 production did not change during exercise. The resting and exercise induced alterations in lymphocyte function and cytokine production were independent of gender and fitness level, and returned to baseline 2 h into recovery. The im-vitro production of IFN-γ and IL-4 suggests that physical activity may alter the balance of TH1 and TH2 lymphocytes.
Abstract Background Exercise is the cornerstone of cardiac rehabilitation (CR). Hospital-based CR exercise programmes are a routine part of clinical care and are typically 6-12 weeks in duration. Following completion, physical activity levels of patients decline. Multi-disease, community-based exercise programmes (MCEP) are an efficient model that could play an important role in the long-term maintenance of positive health behaviours in individuals with cardiovascular disease (CVD) following their medically supervised programme. Aim To explore patients experiences of the initiation and early participation in a MCEP programme and the dimensions that facilitate and hinder physical activity engagement. Methods Individuals with established CVD who had completed hospital-based CR were referred to a MCEP. The programme consisted of twice weekly group exercise classes supervised by clinical exercise professionals. Those that completed (n=31) an initial 10 weeks of the programme were invited to attend a focus group to discuss their experience. Focus groups were transcribed and analysed using reflexive thematic analysis. Results Twenty-four (63% male, 65.5±6.12yrs) patients attended one of four focus groups. The main themes identified were ‘Moving from Fear to Confidence’, ‘Drivers of Engagement,’ and ‘Challenges to Keeping it (Exercise) Up’. Conclusion Participation in a MCEP by individuals with CVD could be viewed as a double-edged sword. Whilst the programme clearly provided an important transition from the clinical to the community setting, there were signs it may breed dependency and not effectively promote independent exercise. Another novel finding was the use of social comparison that provided favourable valuations of performance and increased exercise confidence.
Exercise intensity is an important determinant of energy expenditure (EE) during and following exercise. Recent evidence suggests that total energy expenditure, independent of exercise intensity, may be more important for weight loss programs. Moderate or low intensity exercise will allow for greater fat oxidation rates during exercise but little is known of post-exercise substrate utilisation. PUrPose:The purpose of this study was to determine the impact of low and moderate intensity exercise on substrate utilization and energy expenditure during and after exercise. METHODS:Nine untrained males (age: 23.7 ± 4.7yrs; VO2max: 42.4 ± 4.1ml.kg.min−1) expended 400 kcal in the post-absorptive state on two separate occasions. Exercise was performed at a low intensity (LI; 47 ± 1%VO max) or a moderate intensity (MI; 62 ± 2%VO2max). Substrate oxidation and EE were assessed for 3 hours post exercise using indirect calorimetry. RESULTS:The rate of EE was greater during MI exercise (13.2 ± 0.9 vs. 9.8 ± 0.9 kcal kg min−1, p<0.05) but the duration of exercise was shorter (39.7 ± 4.6 vs. 52.9 ± 6.7 mins, p<0.05). Total fat oxidation during exercise was greater in the LI trial (17.5 + 3.7 vs. 10.9 + 4.1 g, p<0.05). During recovery from exercise, there was a greater reliance on fat oxidation in both the LI trial (81.5 ± 9.6%EE) and the MI trial (79.3 ± 11.6%EE). The rates of fat oxidation and EE in the 3-hrs following exercise were similar between the two trials. CONCLUSIONS: Low intensity exercise elicits greater fat oxidation than isocaloric moderate intensity exercise. Exercise intensity does not affect post-exercise fat oxidation or EE following isocaloric exercise. Low intensity exercise is important for weight loss programs, as long as the duration of exercise is sufficient to allow for adequate energy expenditure.
Background Treatment for peritoneal malignancy (PM) can include cytoreductive surgery (CRS) and heated intrapertioneal chemotherapy (HIPEC) and is associated with morbidity and mortality. Physical, psychological and nutritional outcomes are important pre-operatively. The aim of this pilot study was to investigate these outcomes in patients with PM before and after CRS-HIPEC. Methods Between June 2018 and November 2019, participants were recruited to a single-centre study. Primary outcome was cardiopulmonary exercise testing (CPET) variables oxygen uptake (VO 2 ) at anaerobic threshold (AT) and at peak. Secondary outcome measures were upper and lower body strength, health related quality of life (HRQoL) and the surgical fear questionnaire. Exploratory outcomes included body mass index, nutrient intake and post-operative outcome. All participants were asked to undertake assessments pre CRS-HIPEC and 12 weeks following the procedure. Results Thirty-nine patients were screened, 38 were eligible and 16 were recruited. Ten female and 6 male, median (IQR) age 53 (42–63) years. Of the 16 patients recruited, 14 proceeded with CRS-HIPEC and 10 competed the follow up assessment at week 12. Pre-operative VO 2 at AT and peak was 16.8 (13.7–18) ml.kg -1 .min -1 and 22.2 (19.3–25.3) ml.kg -1 .min -1 , upper body strength was 25.9 (20.3–41.5) kg, lower body strength was 14 (10.4–20.3) sec, HRQoL (overall health status) was 72.5 (46.3–80) % whilst overall surgical fear was 39 (30.5–51). The VO 2 at AT decreased significantly (p = 0.05) and HRQoL improved (p = 0.04) between pre and post- CRS-HIPEC. There were no significant differences for any of the other outcome measures. Conclusion This pilot study showed a significant decrease in VO 2 at AT and an improvement in overall HRQoL at the 12 week follow up. The findings will inform a larger study design to investigate a prehabilitation and rehabilitation cancer survivorship programme.
In this work a robust, non-invasive and wearable micro-fluidic system was developed and employed to analyse pH of sweat in real time during exercise. The device is incorporated in an optical detection platform designed to provide real-time information on sweat composition. The device has been tested
INTRODUCTION: The overall health status of individual’s with chronic disease (CD) are positively and negatively affected by physical activity (PA) and sedentary behavior (SB), respectively. The purpose of this study was to examine the relation between PA, SB and selected indices of health in a diverse CD population using a principal component analysis (PCA). METHODS: Participants (n=237, 54.4% female, age (mean±SD) 62.2±11.1 yr) were recruited at induction to a community-based exercise program for CD. Primary CD included cardiovascular (n=101), respiratory (n=48), cancer (n=80), diabetes (n=34), arthritis (n=26) and unclassified (n=78). BMI and waist to hip ratio (WHR) were measured and calculated using standard procedures. Upper and lower body strength, flexibility and cardiorespiratory fitness were assessed using a hand-grip test, sit-to-stand test (STS), sit and reach test (SRT), and 6-min time trial (6MTT), respectively. PA and SB were recorded using an activPAL3 micro accelerometer. QoL was assessed using the EQ5D VAS and the PHQ8. Fasting serum levels of glucose, triglycerides, HDL-C, LDL-C and CRP were measured. Blood pressure (BP) was measured using a 24-hour ambulatory BP monitor. ActivPAL generated PA and SB variables were analyzed using PCA. General linear models were used to investigate the association between PA and SB and indices of health. RESULTS: PCA analysis of sedentary time, standing time, stepping time, LIPA, MVPA, step count, sedentary bout lengths and total number of sedentary bouts generated three distinct factor; i) prolonged sedentary behavior (PSB), ii) physical activity (PA), and iii) broken sedentary behavior (BSB). The three derived variables account for 86% of the total the variance in PA and SB. There was a significant main effect for PSB on LDL-C (F (1,189) = 9.06) and PHQ8 scores (F(1,162) = 6.82). There was a significant main effect for PA on BMI (F(1,99) = 14.48), WHR (F(1,99) = 5.77), STS (F(1,222) =77.08), 6 MTT (F(1,222) = 77.08), EQ5D VAS (F(1,162) = 14.13), triglycerides (F(1,188) = 4.95), CRP (F(1,155) = 4.28), and systolic BP (F(1,99) = 4.94). There was a significant main effect for BSB on HDL cholesterol (F(1,188) = 6.25). CONCLUSIONS: The PCA derived factors PSB, PA and BSB are associated with established disease risk factors in patients with CD
PURPOSE To characterize and compare the physiological profiles of elite male and female junior middle distance (MD) and long distance (LD) runners. METHODS Maximal oxygen consumption (VO2max) and running economy (RE) were determined in 18 male (18.0 ± 1.6 y) and 14 female (17.1 ± 1.4 y) elite Irish junior MD and LD runners. A series of 6–9 submaximal runs (3 min duration with 1 min recovery) were performed on a treadmill with a 1% inclination, to determine RE and blood lactate levels. The treadmill velocity was increased by 0.5 miles.hr−1 at the beginning of each exercise stage. Following a 1-h recovery period, subjects performed a maximal treadmill test (ramp protocol) to determine VO2max. Expired oxygen, CO2, ventilatory volume (Ve) heart rate (HR) and rating or perceived exertion (RPE) were measured throughout each test. Velocity at VO2max (vVO2max) was calculated by simple linear regression using VO2max and RE. Blood samples were taken during the recovery period following each submaximal run. This was used to determine lactate threshold (LT,) and the onset of blood lactate accumulation at 2 mmol.l−1 (OBLA), the %VO2 at LT (%VO2LT), the %HR at LT (%HRLT), the velocity at LT (Vel-LT). The ventilatory threshold (VT) was determined using the Vslope and Vebreak methods. RESULTS VO2max and vVO2max was higher (p<0.01) in males than females. RE expressed as ml.kg−I·min−I and ml.kg−I.km−I was similar in males and females at 7.0, 7.5, 8.0, 8.5 and 9.0 miles.hr−I and at 60%, 70% and 80%VO2. The %VO2 was lower (P <0.01) in males than females at each treadmill velocity. Males and females were most economical when running at 9.0 miles.hr−I (189.2 ml.kg−I.km−I) and 8.0 miles.hr−I (189.3 ml.kg−I.km−I) respectively. The VO2LT, VO2OBLA, and the VO2 at VT (VO2VT) were greater (p<0.05) in males than females. The Vel-LT, Vel-OBLA, and the treadmill velocity at VT (Vel-VT) were greater (p<0.05) in males than females. The %VO2VT and %HR at the ventilatory threshold (%HRVT) were similar in men and women. In the male athletes, the %VO2LT, %HRLT, and the Vel-LT were lower (P <0.01) than the %VO2VT, %HRVT and the Vel-VT. Females had a lower (P <0.05) %VO2 at LT than at VT. CONCLUSIONS Elite male junior MD and LD runners have a higher VO2max, and greater vVO2max than their female counterparts. The most economical running speed for elite junior female and male MD and LD runners is 8.0 miles.hr−I and 9.0 miles.hr−I respectively. The VO2LT is higher in males that females. In contrast, the %VO2LT was higher in female than male athletes.
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