The reproducibility of the Bruce protocol exercise test for the determination of aerobic capacity in older women

Long-Chain Omega-3 Fatty Acid Supplementation and Exercise-Induced Muscle Damage: EPA or DHA?

PURPOSE

Long-chain omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) may enhance recovery from exercise-induced muscle damage (EIMD). However, it is unclear if the effects are due to EPA, DHA, or both. The purpose of this investigation was to examine the effect of EPA + DHA, EPA, and DHA compared with placebo (PL) on muscular recovery.

METHODS

Thirty males were randomized to 4 g·d -1 EPA + DHA ( n = 8), EPA ( n = 8), DHA ( n = 7), or PL ( n = 7). After 7-wk supplementation, a downhill running (20 min, 70% V̇O 2max , -16% gradient) plus jumping lunges (5 × 20 reps, 2-min rest intervals) muscle damage protocol was performed. Indices of muscle damage, soreness, muscle function, and inflammation were measured at baseline and throughout recovery. The omega-3 index (O3i; %EPA + %DHA in erythrocytes) was used to track tissue EPA and DHA status.

RESULTS

After supplementation, the O3i was significantly higher than PL in all experimental groups ( P < 0.001). Leg press performance was lower in the PL group at 24 h compared with EPA ( P = 0 .019) and at 72 h for EPA ( P = 0.004) and DHA ( P = 0 .046). Compared with PL, muscle soreness was lower in the DHA ( P = 0.015) and EPA ( P = 0.027) groups at 48 h. Albeit nonsignificant, EPA + DHA tended to attenuate muscle soreness ( d = 1.37) and leg strength decrements ( d = 0.75) compared with PL. Jump performance and power metrics improved more rapidly in the EPA and DHA groups (time effects: P < 0.001). Measures of inflammation, range of motion, and muscle swelling were similar between groups ( P > 0.05).

CONCLUSIONS

Compared with PL, 4 g·d -1 of EPA or DHA for 52 d improves certain aspects of recovery from EIMD. EPA + DHA did not clearly enhance recovery. Equivalent dosing of EPA + DHA may blunt the performance effects observed in EPA or DHA alone.

Pulmonary Capacity, Blood Composition and Metabolism among Coal Mine Workers in High- and Low-Altitude Aboveground and Underground Workplaces

(1) Background: While previous studies revealed how underground mining might adversely affect the cardiopulmonary functions of workers, this study further investigated the differences between under- and aboveground mining at both high and low altitudes, which has received little attention in the literature. (2) Methods: Seventy-one healthy male coal mine workers were recruited, who had worked at least 5 years at the mining sites located above the ground at high (>3900 m; n = 19) and low (<120 m; n = 16) altitudes as well as under the ground at high (n = 20) and low (n = 16) altitudes. Participants’ heart rates, pulmonary functions, total energy expenditure and metabolism were measured over a 5-consecutive-day session at health clinics. (3) Results: Combining the results for both above- and underground locations, workers at high-altitude mining sites had significantly higher peak heart rate (HR), minimum average HR and training impulse as well as energy expenditure due to all substances and due to fat than those at low-altitude sites. They also had significantly higher uric acid, total cholesterol, creatine kinase and N-osteocalcin in their blood samples than the workers at low-altitude mining sites. At underground worksites, the participants working at high-altitude had a significantly higher average respiratory rate than those at low-altitude regions. (4) Conclusion: In addition to underground mining, attention should be paid to high-altitude mining as working under a hypoxia condition at such altitude likely presents physiological challenges.

Effects of Tai-Chi and Running Exercises on Cardiorespiratory Fitness and Biomarkers in Sedentary Middle-Aged Males: A 24-Week Supervised Training Study

This study examined the effectiveness of Tai-Chi and running exercises on cardiorespiratory fitness and biomarkers in sedentary middle-aged adults under 24 weeks of supervised training. Methods Thirty-six healthy middle-aged adults (55.6 ± 5.3 yr) were randomly assigned into Tai-Chi, running and control groups. During a 24-week training period, the Tai-Chi and running groups were asked to perform exercises for 60 min/day and 5 days/week, which were supervised by Tai-Chi and running instructors throughout. Resting heart rate, lean mass, blood pressure and blood lipids were measured, and cardiorespiratory fitness (VO2max, Vmax and Peak heart rate) was assessed at the baseline and the 12- and 24-week interventions. Results Compared to the no-exercise control group, both the Tai-Chi and running groups significantly decreased resting heart rate, diastolic blood pressure and cardiorespiratory fitness and increased lean mass across the training session (p < 0.05). Compared to the Tai-Chi group, the running group showed greater improvement in VO2max and Vmax (p < 0.05) and reduced triglyceride and low-density lipoprotein cholesterol (p < 0.05). Conclusion Both Tai-Chi and running exercise showed beneficial effects on cardiorespiratory fitness and enhanced health-related outcomes in middle-aged adults. Although Tai-Chi exercises were less effective in VO2max than running, Tai-Chi may be considered as a plausible alternative to running exercises that can be achieved in the indoor-based setting.

Effect of Weight Self-Stigma and Self-Esteem on Aerobic Exercise Capacity in Adult Women with Different Body Compositions

Background: Overweight individuals face weight-related stigmatization, driving self-exclusion from exercise and physical activity. The extent to which weight self-stigma and self-esteem are associated with aerobic capacity remains unclear. Therefore, this study aimed to characterize the cardiopulmonary fitness, weight self-stigma, and self-esteem of overweight women and examine whether weight self-stigma and self-esteem predict cardiopulmonary aerobic capacity. Methods: A cross-sectional study was conducted with 66 women stratified into two groups: a normal weight (NW) group and an overweight (OW) group. The mean body mass indexes and ages of the NW and OW groups were 20.4 ± 0.36 kg/m² and 29.5 ± 0.8 kg/m², and 24 ± 7 years and 21 ± 3 years, respectively. Submaximal exercise testing using the modified Bruce treadmill protocol was conducted to measure the predicted oxygen uptake (VO_{2 peak}) and energy expenditure. The Weight Self-Stigma Questionnaire and the Rosenberg Self-Esteem Scale were used. Results: Significantly lower mean of predicted VO_{2 peak} and higher mean of energy expenditure were reported in the OW group compared with the NW group (25.8 ± 5.3 mL/kg/min vs. 28.7 ± 4.8 mL/kg/min, p = 0.001 and 9.7 ± 1.9 kcal/min vs. 7.5 ± 1.8 kcal, p = 0.03, respectively). There was a significant difference in weight self-stigma and self-esteem between the groups. Regression model analysis indicated that weight self-stigma and self-esteem explained 45% of the variance in the predicted VO_{2 peak}. Conclusion: Strategies enhancing self-esteem and avoiding stigmatization should be embraced to promote fitness and engagement in physical activity among OW women.

Comparison of constant load exercise intensity for verification of maximal oxygen uptake following a graded exercise test in older adults

Maximal oxygen uptake (VO2 max) declines with advancing age and is a predictor of morbidity and mortality risk. The purpose here was to assess the utility of constant load tests performed either above or below peak work rate obtained from a graded exercise test for verification of VO2 max in older adults. Twenty-two healthy older adults (9M, 13F, 67 ± 6 years, BMI: 26.3 ± 5.1 kg·m-2 ) participated in the study. Participants were asked to complete two experimental trials in a randomized, counterbalanced cross-over design. Both trials (cycle ergometer) consisted of (1) an identical graded exercise test (ramp) and (2) a constant load test at either 85% (CL85; n = 22) or 110% (CL110; n = 20) of the peak work rate achieved during the associated ramp (performed 10-min post ramp). No significant differences were observed for peak VO2 (L·min-1 ) between CL85 (1.86 ± 0.72; p = 0.679) or CL110 (1.79 ± 0.73; p = 0.200) and the associated ramp (Ramp85, 1.85 ± 0.73; Ramp110, 1.85 ± 0.57). Using the study participant's mean coefficient of variation in peak VO2 between the two identical ramp tests (2.9%) to compare individual differences between constant load tests and the associated ramp revealed 19/22 (86%) of participants achieved a peak VO2 during CL85 that was similar or higher versus the ramp, while only 13/20 (65%) of participants achieved a peak VO2 during CL110 that was similar or higher versus the ramp. These data indicate that if a verification of VO2 max is warranted when testing older adults, a constant load effort at 85% of ramp peak power may be more likely to verify VO2 max as compared to an effort at 110% of ramp peak power.

A scoping review of exercise referral schemes involving qualified exercise professionals in primary health care

Qualified exercise professionals (QEPs) have the training, knowledge, and scope of practice to effectively provide physical activity counselling, prescribe exercise, and deliver exercise programming to patients with or without chronic diseases. Healthcare providers identify an interest in referring patients to QEPs; however, the impact of exercise referral schemes (ERS) involving QEPs on patients' physical health is unclear. A scoping review regarding the available evidence of ERS involving healthcare provider referrals to QEPs was performed. A literature search was conducted in 6 databases (initially: n = 6011 articles), yielding n = 23 articles examining QEP delivered physical activity counselling (n = 7), QEP supervised exercise training (n = 4), or some combination (n = 12). Although studies were heterogeneous in methods, procedures, and populations, ERSs increased patients' subjective physical activity levels. Few studies incorporated objective physical activity measures (n = 5/23), and almost half measured aerobic fitness (n = 11/23). ERS involving a QEP that includes activity counselling and/or exercise programming/training report favourable impacts on patients' subjectively measured physical activity and objectively measured aerobic fitness. Based on the existing literature on the topic, this scoping review provides recommendations for designing and evaluating ERS with QEPs that include: objective measures, long-term follow-up, QEP qualifications, and the cost-effectiveness of ERS. Novelty: ERS involving QEPs report increased patients' perceived physical activity level and may improve patients' cardiorespiratory fitness. Promoting the collaboration of QEPs with other healthcare providers can enhance patients' physical fitness and health. This scoping review provides recommendations for the design and evaluation of ERS involving QEPs.

Rationale and design of the Medical Research Council's Precision Medicine with Zibotentan in Microvascular Angina (PRIZE) trial

Microvascular angina is caused by cardiac small vessel disease, and dysregulation of the endothelin system is implicated. The minor G allele of the non-coding single nucleotide polymorphism (SNP) rs9349379 enhances expression of the endothelin 1 gene in human vascular cells, increasing circulating concentrations of ET-1. The prevalence of this allele is higher in patients with ischemic heart disease. Zibotentan is a potent, selective inhibitor of the ETA receptor. We have identified zibotentan as a potential disease-modifying therapy for patients with microvascular angina. METHODS: We will assess the efficacy and safety of adjunctive treatment with oral zibotentan (10 mg daily) in patients with microvascular angina and assess whether rs9349379 (minor G allele; population prevalence ~36%) acts as a theragnostic biomarker of the response to treatment with zibotentan. The PRIZE trial is a prospective, randomized, double-blind, placebo-controlled, sequential cross-over trial. The study population will be enriched to ensure a G-allele frequency of 50% for the rs9349379 SNP. The participants will receive a single-blind placebo run-in followed by treatment with either 10 mg of zibotentan daily for 12 weeks then placebo for 12 weeks, or vice versa, in random order. The primary outcome is treadmill exercise duration using the Bruce protocol. The primary analysis will assess the within-subject difference in exercise duration following treatment with zibotentan versus placebo. CONCLUSION: PRIZE invokes precision medicine in microvascular angina. Should our hypotheses be confirmed, this developmental trial will inform the rationale and design for undertaking a larger multicenter trial.

Ubiquitin Proteasome System Activity is Suppressed by Curcumin following Exercise-Induced Muscle Damage in Human Skeletal Muscle

PURPOSE

Curcumin is a polyphenolic compound that is suggested to dysregulate the ubiquitin-proteasome system (UPS). This study investigated the effects of curcumin supplementation on markers of UPS activity in response to muscle damage.

METHODS

Twenty-three recreationally active male and females between the ages of 18-30 were randomized into a curcumin (CUR) or placebo (PLA) group. Both groups ingested 2 g of their respective supplement and 20 mg of piperine for 11 consecutive days. Following 8 consecutive days of supplementation, participants performed a 45-minute eccentrically-biased treadmill protocol at 60% VO2max. Muscle biopsies and delayed onset muscle soreness (DOMS) assessments were performed 30 minutes prior and 3, 24, 48, and 72 hours following exercise. Skeletal muscle ubiquitin, MAFbx/Atrogin-1, ubiquitin specific peptidase 19 (USP19), and chymotrypsin-like protease concentrations were measured using ELISA. A 3-way repeated measures ANOVA with pairwise comparisons was conducted with significance set at p ≤ 0.05.

RESULTS

Compared to baseline, DOMS for both groups was significantly increased (p < 0.05) at all time points except 72 hours following exercise. No significant differences were found for USP19 between groups. Ubiquitin (p=.016) and MAFbx/Atrogin-1 (p=.006) were significantly lower for CUR compared to PLA. Additionally, MAFbx/Atrogin-1 was significantly greater for females (p=.013) compared to males. In males, curcumin resulted in significant reductions (p = .049) in chymotrypsin-like protease (p = .049).

CONCLUSION

While elevations in UPS activity were not observed in response to muscle damage, curcumin supplementation in humans does appear to dysregulate basal UPS activity in the presence of exercise-induced muscle damage.

Severe-intensity constant-work-rate cycling indicates that ramp incremental cycling underestimates ⩒o2max in a heterogeneous cohort of sedentary individuals

In the absence of a ⩒o2-work-rate plateau, debate continues regarding the best way to verify that the peak ⩒o2 achieved during incremental exercise (⩒o2peak) is the "true ⩒o2max." Oft-used "secondary criteria" have been questioned in conjunction with the contention that a severe-intensity constant-work-rate "verification bout" should be considered the "gold standard." The purpose of this study was to compare the ⩒o2peak during ramp incremental cycling (RAMP-INC) by a heterogeneous (with respect to body composition and sex) cohort of sedentary individuals with the ⩒o2peak during severe-intensity constant-work-rate cycling (CWR) performed after RAMP-INC at the highest work rate achieved. A secondary purpose was to determine the degree to which traditional and newly-proposed age-dependent secondary criteria (RER, HR) identified RAMP-INC which CWR confirmed were characterized by a submaximal ⩒o2peak. Thirty-five healthy male (n = 19: 33.4 ± 6.3 yrs) and female (26.8 ± 3.6 yrs) sedentary participants performed RAMP-INC followed by CWR. The ⩒o2peak values from the two tests were correlated (r = 0.96; p < 0.01; mean CV = 24%); however, ⩒o2peak for CWR was significantly greater (29.6 ± 7.2 v. 28.6 ± 6.8 mL∙min-1∙kg-1; p < 0.01) with a mean bias of 0.98 mL∙min-1∙kg-1 (z = -2.9, p < 0.01). Both traditional and newly-proposed criterion values for RER were achieved during RAMP-INC by 33 of 35 participants (including 21 of 23 who registered a higher ⩒o2peak on CWR). The traditional HR criterion value was achieved on only seven tests (three of which were confirmed to be characterized by a submaximal ⩒o2peak) while use of less stringent newly-proposed criteria resulted in acceptance of an additional seven tests of which five were confirmed to be submaximal. Severe-intensity CWR to limit of tolerance indicates that RAMP-INC underestimates ⩒o2max in sedentary individuals and both traditional and newly-proposed secondary criteria are ineffective for identifying such tests.

High-Intensity Interval Circuit Training Versus Moderate-Intensity Continuous Training on Cardiorespiratory Fitness in Middle-Aged and Older Women: A Randomized Controlled Trial

High-intensity interval training (HIIT) has similar or better effects than moderate-intensity continuous training (MICT) in increasing peak oxygen consumption (VO_2max), however, it has not been studied when HIIT is applied in a circuit (HIICT). The aim of this study was to compare the effects of a HIICT versus MICT on VO_2max estimated (VO_2max-ES), heart rate (HR) and blood pressure (BP) of middle-aged and older women. A quasi-experimental randomized controlled trial was used. Fifty-four women (67.8 ± 6.2 years) were randomized to either HIICT (n = 18), MICT (n = 18) or non-exercise control group (CG; n = 18) for 18 weeks. Participants in HIICT and MICT trained two days/week (one hour/session). Forty-one participants were assessed (HIICT; n = 17, MICT; n = 12, CG; n = 12). Five adverse events were reported. Cardiorespiratory fitness, HR and BP were measured. The tests were performed before and after the exercise intervention programs. VO_2max-ES showed significant training x group interaction, in which HIICT and MICT were statistically superior to CG. Moreover, HIICT and MICT were statistically better than CG in the diastolic blood pressure after exercise (DBP_ex) interaction. For the systolic blood pressure after exercise (SBP_ex), HIICT was statistically better than CG. In conclusion, both HIICT and MICT generated adaptations in VO_2max-ES and DBP_ex. Furthermore, only HIICT generated positive effects on the SBP_ex. Therefore, both training methods can be considered for use in exercise programs involving middle-aged and older women.

Habitual exercise training in older adults offsets the age-related prolongation in leg vasodilator kinetics during single-limb lower body exercise

We tested the hypothesis that aging is associated with prolonged leg vasodilator kinetics and habitual exercise training in older adults improves these responses relative to untrained older adults. Additionally, we examined the relationship between contraction-induced rapid onset vasodilation (ROV) and vasodilator kinetics. Young ( n = 10), older untrained ( n = 13), and older trained ( n = 14) adults performed single and rhythmic knee-extension contractions at 20% and 40% work-rate maximum (WR_max). Femoral artery diameter and mean blood velocity were measured by Doppler ultrasound. Vascular conductance (VC; ml·min^-1·mmHg^-1) was calculated using blood flow (ml/min) and mean arterial pressure (mmHg). The primary outcome was the kinetic response (mean response time; MRT), modeled using an exponential model, expressed as the number of duty cycles to change 63% of the steady-state amplitude. There were no age- or training-related differences in VC MRT between the groups at 20% WR_max. Older untrained adults exhibited prolonged VC MRT at 40% WR_max relative to young (37 ± 16 vs. 24 ± 10 duty-cycles; P < 0.05) and older trained adults (37 ± 16 vs. 23 ± 14 duty-cycles; P < 0.05). There were no differences in VC MRT between young and older trained adults at 40% WR_max ( P = 0.96). There were no associations between peak ROV and VC MRT at 20% or 40% WR_max ( r = -0.08 and 0.22; P = 0.67 and 0.20, respectively) in the group as a whole. Our data suggest 1) advancing age prolongs leg vasodilator kinetics; 2) habitual exercise training in older adults offsets this age-related prolongation; and 3) contraction-induced ROV is not related to vasodilator kinetics within a group of young and older adults. NEW & NOTEWORTHY Aging is associated with reductions in exercise hyperemia and vasodilation at the onset of exercise, as well as during steady-state exercise. Habitual endurance exercise training offsets these age-related reductions. We found that aging prolongs vasodilator kinetics in the leg of older untrained but not older trained adults. Finally, our results demonstrate that contraction-induced rapid vasodilation is not associated with vasodilator kinetics within the leg of young and older adults.

Physiological Adaptations to Hypoxic vs. Normoxic Training during Intermittent Living High

In the setting of “living high,” it is unclear whether high-intensity interval training (HIIT) should be performed “low” or “high” to stimulate muscular and performance adaptations. Therefore, 10 physically active males participated in a 5-week “live high-train low or high” program (TR), whilst eight subjects were not engaged in any altitude or training intervention (CON). Five days per week (~15.5 h per day), TR was exposed to normobaric hypoxia simulating progressively increasing altitude of ~2,000–3,250 m. Three times per week, TR performed HIIT, administered as unilateral knee-extension training, with one leg in normobaric hypoxia (~4,300 m; TR_HYP) and with the other leg in normoxia (TR_NOR). “Living high” elicited a consistent elevation in serum erythropoietin concentrations which adequately predicted the increase in hemoglobin mass (r = 0.78, P < 0.05; TR: +2.6%, P < 0.05; CON: −0.7%, P > 0.05). Muscle oxygenation during training was lower in TR_HYP vs. TR_NOR (P < 0.05). Muscle homogenate buffering capacity and pH-regulating protein abundance were similar between pretest and posttest. Oscillations in muscle blood volume during repeated sprints, as estimated by oscillations in NIRS-derived tHb, increased from pretest to posttest in TR_HYP (~80%, P < 0.01) but not in TR_NOR (~50%, P = 0.08). Muscle capillarity (~15%) as well as repeated-sprint ability (~8%) and 3-min maximal performance (~10–15%) increased similarly in both legs (P < 0.05). Maximal isometric strength increased in TR_HYP (~8%, P < 0.05) but not in TR_NOR (~4%, P > 0.05). In conclusion, muscular and performance adaptations were largely similar following normoxic vs. hypoxic HIIT. However, hypoxic HIIT stimulated adaptations in isometric strength and muscle perfusion during intermittent sprinting.

Influence of chronic endurance exercise training on conduit artery retrograde and oscillatory shear in older adults

PURPOSE

With aging, there tends to be an increase in retrograde and oscillatory shear in peripheral conduit arteries of humans. Whether the increase in shear rate is due to the aging process or an effect of a less active lifestyle that often accompanies aging is unknown. Therefore, we examined whether chronic endurance exercise training attenuates conduit artery retrograde and oscillatory shear in older adults.

METHODS

Brachial and common femoral artery mean blood velocities and diameter were determined via Doppler ultrasound under resting conditions, and shear rate was calculated in 13 young (24 ± 2 years), 17 older untrained (66 ± 3 years), and 16 older endurance exercise-trained adults (66 ± 7 years).

RESULTS

Brachial artery retrograde (-9.1 ± 6.4 vs. -12.6 ± 9.4 s(-1); P = 0.35) and oscillatory (0.14 ± 0.08 vs. 0.14 ± 0.08 arbitrary units; P = 0.99) shear were similar between the older trained and untrained groups, whereas brachial artery retrograde and oscillatory shear were greater in older untrained compared to young adults (-5.0 ± 3.4, 0.08 ± 0.05 s(-1) arbitrary units, P = 0.017 and 0.048, respectively). There was no difference between the young and older trained brachial retrograde (P = 0.29) and oscillatory (P = 0.07) shear. Common femoral artery retrograde (-6.3 ± 2.9 s(-1)) and oscillatory (0.21 ± 0.08 arbitrary units) shear were reduced in older trained compared to the older untrained group (-10.4 ± 4.1 and 0.30 ± 0.09 s(-1) arbitrary units, both P = 0.005 and 0.006, respectively), yet similar to young adults (-7.1 ± 3.5 and 0.19 ± 0.06 s(-1) arbitrary units, P = 0.81 and 0.87, respectively).

CONCLUSION

Our results suggest that chronic endurance exercise training in older adults ameliorates retrograde and oscillatory shear rate patterns, particularly in the common femoral artery.

Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation

Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59-0.64) and leg exercise intensities (r = 0.55-0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults.

Cardiorespiratory fitness in older adult women: relationships with serum 25-hydroxyvitamin D

Previous studies suggest that circulating 25(OH)D may favorably influence cardiorespiratory fitness and fat oxidation. However, these relationships have not been examined in older adult women of different ethnic groups. The objectives of this study were to determine whether serum 25(OH)D is related to cardiovascular fitness (VO2max) in sedentary women ages ≥60 years and to determine whether these associations differ between African Americans (AA) and European Americans (EA). A secondary aim was to determine whether serum 25(OH)D is correlated with respiratory quotient (RQ) during submaximal exercise. This cross-sectional analysis included 67 AA and EA women ages 60-74 years. VO2max was measured by a modified Bruce graded treadmill protocol, and measurements were adjusted for percent fat and lean body mass assessed by air displacement plethysmography. Indirect calorimetry was used to measure RQ at rest and during four submaximal exercise tests. Fasting blood samples were obtained to quantify serum 25(OH)D. Serum 25(OH)D was associated with VO2max (ml/kg LBM/min) independent of percent body fat (r = 0.316, p = 0.010). However, subgroup analysis revealed that this relationship was specific to AA (r = 0.727, p = 0.005 for AA; r = 0.064, p = 0.643 for EA). In all subjects combined, 25(OH)D was inversely correlated (p < 0.01) with all measures of submaximal RQ. Higher serum 25(OH)D was associated with greater cardiorespiratory fitness in older adult AA women. Among both AA and EA, inverse associations between serum 25(OH)D and RQ suggest that women with higher levels of circulating vitamin D also demonstrated greater fat oxidation during submaximal exercise.

Assessment of aerobic capacity and walking economy of unilateral transfemoral amputees

BACKGROUND

Studies of the maximal oxygen uptake (VO(2max)) of transfemoral amputees have mostly used protocols that activate a relatively small muscle mass. Consequently, transfemoral amputee VO(2max) may be systematically underestimated, and the validity of these test protocols is questionable.

OBJECTIVES

(1) Investigate validity and reliability of a VO(2max) walking protocol and (2) compare the VO(2max) of a transfemoral amputee group with a group of matching controls.

STUDY DESIGN

(1) Randomized crossover study: walking versus running VO(2max) for the control group and (2) case-control study: transfemoral amputees versus control group VO(2max).

METHODS

Twelve transfemoral amputees and control participants performed a walking VO(2max) test with increasing treadmill inclinations to voluntary exhaustion. The control group also completed a running ("gold-standard") VO(2max) test.

RESULTS

Mean (standard deviation) control group VO(2max) following walking and running was similar, that is, 2.99 (0.6) L min(-1) and 3.09 (0.7) L min(-1), respectively. Mean (standard deviation) transfemoral amputee walking VO(2max) was 2.14 (0.8) L min(-1) (compared to CON; p < 0.01). Mean intraclass correlation coefficient of repeated VO(2) measurements was 0.97, and within-subjects standard deviation was 60 mL min(-1).

CONCLUSIONS

The walk protocol is valid. Walking VO(2max) of transfemoral amputees was 40% lower compared to control group. Reliability of the walking protocol is comparable to other walking protocols. Clinical relevance The design, alignment, and materials of prostheses are important for effective ambulation. Cardio-respiratory fitness is, however, also important in this regard, and a low fitness may compromise health and independent living. Hence, transfemoral amputees with low physical fitness should engage in regular physical activity to improve health, gait capacity, and independency.

Feasibility and efficacy of a supervised exercise intervention in de-conditioned cancer survivors during the early survivorship phase: the PEACH trial

PURPOSE

This study aims to evaluate the feasibility and efficacy of an 8-week supervised exercise program in de-conditioned cancer survivors within 2-6 months of chemotherapy completion.

METHODS

Participants were randomly assigned to an 8-week, twice-weekly, supervised aerobic exercise training regime (n = 23) or a usual care group (n = 20). Feasibility was assessed by recruitment rate, program adherence and participant feedback. The primary outcome was aerobic fitness assessed by the Modified Bruce fitness test at baseline (0 weeks), post-intervention (8 weeks) and at 3-month follow-up. Secondary outcomes included physical activity, waist circumference, fatigue and quality of life.

RESULTS

The recruitment rate was 81 % and adherence to the supervised exercise was 78.3 %. Meaningful differences in aerobic fitness between the exercise and usual care groups at both the 8-week [mean 3.0 mL kg(-1) min(-1) (95 % CI -1.1-7.0)] and 3-month follow-up [2.1 mL kg(-1) min(-1) (-2.3-6.6)] were found, although these differences did not achieve statistical significance (p values >0.14). Self-reported physical activity increased in the exercise group (EG) compared to the usual care group at both 8-week (p = 0.01) and 3-month follow-up (p = 0.03) and significant differences in favour of the EG were found for physical well-being at both the 8-week (p = 0.03) and 3-month follow-up (p = 0.04). Improvements in fatigue (p = 0.01), total quality of life plus fatigue (p = 0.04), and a composite physical functioning score (p = 0.01) at the 3-month follow-up were also found.

CONCLUSION

The PEACH trial suggests that 8 weeks of supervised aerobic exercise training was feasible and may improve aerobic fitness, fatigue and quality of life in de-conditioned cancer survivors during the early survivorship phase.

IMPLICATIONS FOR CANCER SURVIVORS

Exercise interventions commenced in the early survivorship phase appear safe, feasible and may lead to improvements in QOL and fatigue.

Feasibility and efficacy of a supervised exercise intervention in de-conditioned cancer survivors during the early survivorship phase: the PEACH trial

PURPOSE

This study aims to evaluate the feasibility and efficacy of an 8-week supervised exercise program in de-conditioned cancer survivors within 2-6 months of chemotherapy completion.

METHODS

Participants were randomly assigned to an 8-week, twice-weekly, supervised aerobic exercise training regime (n = 23) or a usual care group (n = 20). Feasibility was assessed by recruitment rate, program adherence and participant feedback. The primary outcome was aerobic fitness assessed by the Modified Bruce fitness test at baseline (0 weeks), post-intervention (8 weeks) and at 3-month follow-up. Secondary outcomes included physical activity, waist circumference, fatigue and quality of life.

RESULTS

The recruitment rate was 81 % and adherence to the supervised exercise was 78.3 %. Meaningful differences in aerobic fitness between the exercise and usual care groups at both the 8-week [mean 3.0 mL kg(-1) min(-1) (95 % CI -1.1-7.0)] and 3-month follow-up [2.1 mL kg(-1) min(-1) (-2.3-6.6)] were found, although these differences did not achieve statistical significance (p values >0.14). Self-reported physical activity increased in the exercise group (EG) compared to the usual care group at both 8-week (p = 0.01) and 3-month follow-up (p = 0.03) and significant differences in favour of the EG were found for physical well-being at both the 8-week (p = 0.03) and 3-month follow-up (p = 0.04). Improvements in fatigue (p = 0.01), total quality of life plus fatigue (p = 0.04), and a composite physical functioning score (p = 0.01) at the 3-month follow-up were also found.

CONCLUSION

The PEACH trial suggests that 8 weeks of supervised aerobic exercise training was feasible and may improve aerobic fitness, fatigue and quality of life in de-conditioned cancer survivors during the early survivorship phase.

IMPLICATIONS FOR CANCER SURVIVORS

Exercise interventions commenced in the early survivorship phase appear safe, feasible and may lead to improvements in QOL and fatigue.

Protease supplementation improves muscle function after eccentric exercise

Protease supplementation has been purported to reduce the damaging effects of eccentric exercise and accelerate recovery of muscle function, possibly by regulating inflammation.

PURPOSE

To determine the effectiveness of protease supplementation in attenuating eccentric exercise-induced skeletal muscle damage and inflammation.

METHODS

After standard physical and hemodynamic assessment and fasting venous blood samples, subjects performed isokinetic extension/flexion of the quadriceps group on a Biodex isokinetic dynamometer at 60°·s(-1), followed by VO2max testing. Subjects were randomly assigned to consume 5.83 g daily of either a cellulose placebo (N = 15; 22.27 ± 3.33 yr, 71.17 ± 2.91 inches, 179.4 ± 24.05 lb, 50.55 ± 5.66 mL·kg(-1)·min(-1)) or a proteolytic supplement containing fungal proteases, bromelain, and papain (N = 14; 22.85 ± 5.9 yr, 70.0 ± 2.67 inches, 173.11 ± 29.94 lb, 49.69 ± 6.15 mL·kg(-1)·min(-1)) for a period of 21 d. After the supplementation period, subjects donated blood samples before performing a 45-min downhill (-17.5%) treadmill protocol at 60% of VO2max. An additional four blood draws and three muscle function tests were performed during the next 48 h. Blood was analyzed using standard hematology and clinical chemistry, enzyme-linked immunosorbent assay, and bead array. Blood data were analyzed using multivariate analysis of variance (MANOVA) with repeated measures, whereas Biodex data were analyzed using a MANOVA on %Δ values.

RESULTS

Significant group differences (T1-T3, P = 0.033; T1-T4, P = 0.043) and another strong trend (T1-3 h, P = 0.055) were observed for flexion (peak torque %Δ at 60°·s(-1)) indicating higher force production in the protease group. Significant group × time interactions (P < 0.05) were observed, including elevations in circulating eosinophils and basophils in the protease group coinciding with lower levels of serum cyclooxygenase 2, interleukin 6, and interleukin 12 in this group.

CONCLUSIONS

Protease supplementation seems to attenuate muscle strength losses after eccentric exercise by regulating leukocyte activity and inflammation.

Reliability of a graded exercise test for assessing recovery from concussion

OBJECTIVE

To evaluate a graded treadmill test for retest reliability (RTR) and interrater reliability (IRR) in the evaluation of the physiologic effects of symptom exacerbation from concussion.

DESIGN

Prospective case series (RTR) and blinded rater assessment of 10 actors portraying patients with and without symptom exacerbation (IRR).

SETTING

University Sports Medicine Concussion Clinic.

PARTICIPANTS

For RTR, 21 refractory concussed patients (11 athletes and 10 nonathletes) and 10 healthy subjects; for IRR, 32 raters representing a variety of health care disciplines.

INTERVENTION

For RTR, a Balke protocol treadmill test to symptom exacerbation before and after 2 to 3 weeks. For IRR, video recordings of actors during the treadmill test viewed by raters blinded to condition.

MAIN OUTCOME MEASURES

For RTR, agreement of the tests for maximal heart rate (HR), systolic blood pressure, diastolic blood pressure, and rating of perceived exertion. For IRR, presence or absence of symptom exacerbation and the symptom exacerbation HR.

RESULTS

Raters achieved a sensitivity of 99% for identifying actors with symptom exacerbation and a specificity of 89% for ruling out concussion symptoms and agreed on 304 of 320 observations (accuracy of 95%). The intraclass correlation coefficient for the symptom exacerbation HR was large at 0.90 (95% confidence interval, 0.78-0.98). The treadmill test had good RTR for maximum HR (intraclass correlation coefficient, 0.79) but not for systolic blood pressure, diastolic blood pressure, or rating of perceived exertion.

CONCLUSIONS

The Balke exercise treadmill protocol has very good IRR and sufficient RTR for identifying patients with symptom exacerbation from concussion.

Thermoregulatory efficiency is increased after heat acclimation in tropical natives

To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40+/-0 degrees C and 45.1+/-0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32+/-5%) in comparison to the trunk (11+/-2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs' sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency.

Effects of eccentric treadmill exercise on inflammatory gene expression in human skeletal muscle

The present study examined the skeletal muscle expression of several genes related to the inflammatory process before and after a bout of downhill running. Twenty-nine males between the ages of 18 and 35 years performed a 45-min downhill (-17.5%) treadmill protocol at 60% of maximal oxygen consumption. Venous bloods samples and muscle biopsy samples from the vastus lateralis were donated prior to and at 3-h and 24-h postexercise, along with ratings of perceived muscle soreness. Serum creatine kinase (CK) was determined, as was skeletal muscle gene expression of interleukin (IL)-6, IL-8, IL-12 (p35), tumor necrosis factor-alpha (TNF-alpha), IL-1beta, cyclooxygenase 2 (COX2), and nuclear factor kappa B (NFkB) (p105/p50). Gene expression was analyzed using RT-PCR and compared with a standard housekeeping gene (beta-actin). Data were analyzed for statistical differences using multivariate analysis of variance with univariate follow-up. In addition, Pearson correlations were conducted to determine if any significant relationship exists between any of these transcripts and both CK and muscle soreness. Significant (p < 0.05) up-regulations in IL-6, IL-8, and COX2 mRNA expression were observed compared with baseline, whereas no significant changes for IL-12, IL-1beta, TNF-alpha, or NFkB were noted. Significant increases in IL-6 mRNA were observed at 3 h (p < 0.001) and 24 h (p = 0.043), whereas significant increases in IL-8 (p = 0.001) and COX2 (p = 0.046) mRNA were observed at 3-h postexercise. In addition, muscle soreness was significantly correlated with IL-8 at 24 h (r = -0.370; p = 0.048), whereas CK was significantly related to NFkB at baseline (r = -0.460; p = 0.012). These data indicate that increases in the mRNA expression of IL-6, IL-8, and COX2 occur in the vastus lateralis as a result of damaging eccentric exercise in young, recreationally trained males. Further, it appears that IL-8 transcription may play some role in inhibiting postexercise muscle soreness, possibly through regulation of angiogenesis.

Effects of acute and 14-day coenzyme Q10 supplementation on exercise performance in both trained and untrained individuals

Background

To determine whether acute (single dose) and/or chronic (14-days) supplementation of CoQ10 will improve anaerobic and/or aerobic exercise performance by increasing plasma and muscle CoQ10 concentrations within trained and untrained individuals.

Methods

Twenty-two aerobically trained and nineteen untrained male and female subjects (26.1 ± 7.6 yrs, 172 ± 8.7 cm, 73.5 ± 17 kg, and 21.2 ± 7.0%) were randomized to ingest in a double-blind manner either 100 mg of a dextrose placebo (CON) or a fast-melt CoQ10 supplement (CoQ10) twice a day for 14-days. On the first day of supplementation, subjects donated fasting blood samples and a muscle biopsy. Subjects were then given 200 mg of the placebo or the CoQ10 supplement. Sixty minutes following supplement ingestion, subjects completed an isokinetic knee extension endurance test, a 30-second wingate anaerobic capacity test, and a maximal cardiopulmonary graded exercise test interspersed with 30-minutes of recovery. Additional blood samples were taken immediately following each exercise test and a second muscle biopsy sample was taken following the final exercise test. Subjects consumed twice daily (morning and night), 100 mg of either supplement for a period of 14-days, and then returned to the lab to complete the same battery of tests. Data was analyzed using repeated measures ANOVA with an alpha of 0.05.

Results

Plasma CoQ10 levels were significantly increased following 2 weeks of CoQ10 supplementation (p < 0.001); while a trend for higher muscle CoQ10 levels was observed after acute CoQ10 ingestion (p = 0.098). A trend for lower serum superoxide dismutase (SOD) was observed following acute supplementation with CoQ10 (p = 0.06), whereas serum malondialdehyde (MDA) tended to be significantly higher (p < 0.05). Following acute ingestion of CoQ10, plasma CoQ10 levels were significantly correlated to muscle CoQ10 levels; maximal oxygen consumption; and treadmill time to exhaustion. A trend for increased time to exhaustion was observed following 2 weeks of CoQ10 supplementation (p = 0.06).

Conclusion

Acute supplementation with CoQ10 resulted in higher muscle CoQ10 concentration, lower serum SOD oxidative stress, and higher MDA levels during and following exercise. Chronic CoQ10 supplementation increased plasma CoQ10 concentrations and tended to increase time to exhaustion. Results indicate that acute and chronic supplementation of CoQ10 may affect acute and/or chronic responses to various types of exercise.

Effect of the VO2 time-averaging interval on the reproducibility of VO2max in healthy athletic subjects

AIMS

Limited research has investigated the most appropriate oxygen uptake (VO2) data averaging method to obtain reliable and valid maximal oxygen uptake (VO2max) values. This study investigated the effect of the VO2 time-averaging interval on the reproducibility of VO2max.

METHODS AND RESULTS

Twenty-two competitive distance runners (six female) performed two identical incremental treadmill tests to their limit of exercise tolerance separated by at least 48 h. Commencing at 7 km h(-1), running speed was increased by 1 km h(-1) per minute for five stages and 0.5 km h(-1) thereafter. Breath-by-breath VO2 data collected during each incremental test were time-averaged over 10-, 15-, 20-, 30- and 60-s and the highest averaged VO2 value was regarded as VO2max for each time-averaging interval. The VO2max values derived from different VO2 time-averaging intervals were significantly different for the first (F = 39.6; P<0.001) and second (F = 68.9; P<0.001) incremental test. There was a tendency for VO2max to significantly increase as the time-averaging interval became shorter. The reproducibility of VO2max was similar for all five VO2 time-averages, with no significant differences between the within-subject variance (F = 0.4; P = 0.6).

CONCLUSION

The results of this study suggests that the reproducibility of VO2max is not affected by the length of the VO2 time-average interval. However, VO2max was significantly altered by changing the VO2 time-averaging interval between 10 and 60 s. Consistency in the VO2 time-averaging interval is therefore an important methodological consideration for repeated determinations of VO2max.

Pharmacokinetics, safety, and effects on exercise performance of l-arginine α-ketoglutarate in trained adult men

OBJECTIVE

We evaluated the pharmacokinetics, safety, and efficacy of l-arginine alpha-ketoglutarate (AAKG) in trained adult men.

METHODS

Subjects participated in two studies that employed a randomized, double-blind, controlled design. In study 1, 10 healthy men (30-50 y old) fasted for 8 h and then ingested 4 g of time-released or non-timed-released AAKG. Blood samples were taken for 8 h after AAKG ingestion to assess the pharmacokinetic profile of L-arginine. After 1 wk the alternative supplement was ingested. In study 2, which was placebo controlled, 35 resistance-trained adult men (30-50 y old) were randomly assigned to ingest 4 g of AAKG (three times a day, i.e., 12 g daily, n = 20) or placebo (n = 15). Participants performed 4 d of periodized resistance training per week for 8 wk. At 0, 4, and 8 wk of supplementation the following tests were performed: clinical blood markers, one repetition maximum bench press, isokinetic quadriceps muscle endurance, anaerobic power, aerobic capacity, total body water, body composition, and psychometric parameters tests. Data were analyzed by repeated measures analysis of variance.

RESULTS

In study 1, significant differences were observed in plasma arginine levels in subjects taking non-timed-release and timed-release AAKG. In study 2, significant differences were observed in the AAKG group (P < 0.05) for 1RM bench press, Wingate peak power, blood glucose, and plasma arginine. No significant differences were observed between groups in body composition, total body water, isokinetic quadriceps muscle endurance, or aerobic capacity.

CONCLUSION

AAKG supplementation appeared to be safe and well tolerated, and positively influenced 1RM bench press and Wingate peak power performance. AAKG did not influence body composition or aerobic capacity.

Reliability of graded exercise testing after traumatic brain injury: submaximal and peak responses

OBJECTIVE

To assess the reliability of the submaximal and peak responses to a treadmill graded exercise test in individuals recovering from traumatic brain injury.

DESIGN

A total of 15 individuals (11 men, 4 women; 28.5 +/- 9.2 yrs) with moderate to severe traumatic brain injury admitted into a postacute residential treatment center 10 +/- 7 mos after injury performed two treadmill graded exercise tests separated by 4-8 days. Heart rate, oxygen consumption (in milliliters per minute per kilogram), minute ventilation (in liters per minute), and respiratory exchange ratio (carbon dioxide output/oxygen consumption) were continuously monitored at 1-min intervals. Submaximal and peak values were analyzed for absolute level of agreement using the intraclass correlation coefficient.

RESULTS

The submaximal intraclass correlation coefficient values for all variables between minutes 3 and 7 ranged from 0.80 to 0.93. Submaximal intraclass correlation coefficients before and in the subsequent minutes were less than optimal for heart rate and minute ventilation. Lower intensity workloads elicited slightly better agreement than higher intensity workloads. The peak response intraclass correlation coefficients ranged from 0.77 (heart rate) to 0.92 (oxygen consumption).

CONCLUSION

Despite the presence of other co-morbidities, subjects recovering from traumatic brain injury provided consistent individual responses, allowing for reliable assessments of cardiorespiratory conditioning programs. Assessments of ambulatory efficiency, endurance, and aerobic fitness adaptations as a result of treatment for persons with traumatic brain injury should include analyses of submaximal responses to graded exercise.

Maximal Aerobic Capacity Testing of Older Adults: A Critical Review

Most of the data that describe maximal oxygen uptake (VO(2max)) and the requirements for its attainment have been developed using young adults as subjects. Many older adults are unable to satisfactorily complete a maximal exercise effort in a standard exercise stress test. This review describes exercise tests currently available to measure VO(2max) in older adults. PubMed and CINAHL databases were searched for studies including healthy individuals older than 65 years with reproducible descriptions of the testing protocol. The research on VO(2max) testing in healthy individuals older than 65 years is limited, does not describe the protocols in detail, and/or lacks information on the psychometric properties of the exercise tests. There is a need for refinement of the few existing protocols for testing aerobic capacity in older adults, as well as the development of new protocols specifically applicable to older adults. Consensus on the criteria defining VO(2max) attainment during exercise in older adults is required, as well as agreement on the most appropriate exercise protocols and equipment, specific to older adults, to successfully fulfil these criteria.

Relationship between elevated FX expression and increased production of GDP-L-fucose, a common donor substrate for fucosylation in human hepatocellular carcinoma and hepatoma cell lines

The levels of fucosylated glycoproteins in various cancers and inflammatory processes have been a subject of intense study. The level of fucosyltransferases and intracellular GDP-L-fucose, a sugar nucleotide and a common donor substrate for all fucosyltransferases, may regulate the level of fucosylated glycoproteins. This study reports on the determination of GDP-L-fucose levels in human hepatocellular carcinoma (HCC) and surrounding tissues, using a recently established high-throughput assay system. Levels of GDP-L-fucose in HCC tissues were significantly increased compared with adjacent nontumor tissues or normal livers. The mean +/- SD for GDP-L-fucose level was 3.6 +/- 0.2 micro mol/mg in control liver, 4.6 +/- 0.9 micro mol/mg in adjacent noninvolved liver tissues (chronic hepatitis, 4.4 +/- 0.7 micro mol/mg; liver cirrhosis, 4.8 +/- 0.9 micro mol/mg), and 7.1 +/- 2.5 micro mol/mg in HCC tissues. The level of GDP-L-fucose in HCC decreased in proportion with tumor size (r = -0.675, P = 0.0002). When expression of the series of genes responsible for GDP-L-fucose synthesis was investigated, the gene expression of FX was found to be increased in 70% (7 of 10) of the HCC tissues examined compared with that in their surrounding tissues. The levels of GDP-L-fucose were positively correlated with the expression of FX mRNA (r = 0.599, P = 0.0074). The levels of FX gene expression in some human hepatoma and hepatocyte cell lines were determined. FX mRNA production was strongly increased in HepG2 and Chang liver, moderately increased in Hep3B and HLF, and, in HLE, was similar to that of a normal human liver tissue. To investigate the effect of GDP-L-fucose on core fucosylation, FX cDNA was transfected into Hep3B cells, which express a relatively low level of GDP-L-fucose:N-acetyl-beta-D-glucosaminide alpha1-6 fucosyltransferase (alpha1-6 FucT) and FX mRNA. Transfection of this gene caused an increase in GDP-L-fucose levels as well as the extent of fucosylation on glycoproteins, including alpha-fetoprotein, as judged by reactivity to lectins. Collectively, the results herein suggest that the high level of fucosylation in HCC is dependent on a high expression of FX followed by increases in GDP-L-fucose, as well as an enhancement in alpha1-6 FucT expression. Thus, an elevation in GDP-L-fucose levels and the up-regulation of FX expression represent potential markers for HCC.

Reliability of treadmill exercise testing in older patients with chronic hemiparetic stroke11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or any organization with which the authors are associated

OBJECTIVE

To assess the test-retest reliability of cardiopulmonary measurements during peak effort and submaximal treadmill walking tests in older patients with gait-impaired chronic hemiparetic stroke.

DESIGN

Nonrandomized test-retest.

SETTING

Hospital geriatric research stress testing laboratory.

PARTICIPANTS

Fifty-three subjects (44 men, 9 women; mean age, 65+/-8y) with chronic hemiparetic gait after remote (>6mo) ischemic stroke. Patients had mild to moderate chronic hemiparetic gait deficits, making handrail support necessary during treadmill walking.

INTERVENTIONS

Peak effort and submaximal effort treadmill walking tests were conducted and then repeated on a separate day at least a week later. Main outcome measures Reliability coefficients (r) were calculated for heart rate, systolic blood pressure (SBP), oxygen consumption (Vo(2) [L/min]), Vo(2) (mL.kg(-1).min(-1)), respiratory exchange ratio (RER), rate-pressure product (RPP), and oxygen pulse during peak effort testing. The reliability coefficients for all but SBP and RPP data were calculated from the submaximal tests.

RESULTS

Heart rate (r=.87), Vo(2)peak (L/min) (r=.92), Vo(2)peak (mL.kg(-1).min(-1)) (r=.92), and oxygen pulse (r=93) were highly reliable parameters during maximal testing in this population. Submaximal testing produced highly reliable results for V.o(2) (L/min) (r=.89) and oxygen pulse (r=.85). All cardiopulmonary measures except RER had a reliability coefficient greater than.80 during submaximal testing in this population.

CONCLUSION

Our study provides the first evidence that peak effort treadmill testing provides highly reliable oxygen consumption measures in chronic hemiparetic stroke patients using minimal handrail support. The submaximal tests were at or near the threshold level of reliability for the 2 most important measures of V.o(2) (L/min) and V.o(2) (mL.kg(-1).min(-1)) (r=.89, r=.84, respectively), with the remaining measures falling above.70.

Basal fat oxidation and after a peak oxygen consumption test in obese women with a beta2 adrenoceptor gene polymorphism

The Glu27Glu genotype in the beta2-adrenergic receptor (ADRB2) has been linked to a higher fat deposition and obesity in females. Also, in our population, it has been described that physically active women carrying the Glu allele had a higher BMI as compared to non-carriers performing the same level of activity. Since exercise may counterbalance a gene predisposition to obesity, we tested the hypothesis of a potential different metabolic response among ADRB2 Gln27Gln versus Glu27Glu obese women when submitted to a peak oxygen consumption test on a treadmill. In our study, 10 obese women with the Gln27Gln genotype were compared to 9 matched obese women bearing the Glu27Glu genotype. The ADRB2 polymorphism was identified by PCR-RFLP, fat oxidation was determined by indirect calorimetry and blood measurements were carried out following conventional procedures. The ADRB2 Glu27Glu subjects had lower plasma glycerol levels (P = 0.026), while plasma triglycerides (P <0.001) and the insulin:glucose ratio were higher (P = 0.046) as compared to the Gln27Gln group along the peak oxygen consumption trial intervention. There was a significantly lower fat oxidation (P = 0.024) in the Glu27Glu obese women during the recovery compared to Gln27Gln obese individuals. These data suggest that exercise would not benefit equally the two ADRB2 polymorphism homozygous groups, since both lipolysis and fat oxidation promoted by a peak oxygen consumption test appear to be blunted in the polymorphic Glu27Glu obese group.

Applicability of maximal oxygen consumption criteria in obese, postmenopausal women

This study examines the applicability of using three standard criteria (age-predicted maximal heart rate [HRmax], respiratory exchange ratio [RER>1.10], and plateau in oxygen uptake [Vo(2)] for the measurement of maximal oxygen consumption (Vo(2)max) in postmenopausal women. One hundred eight postmenopausal (60 +/- 6 years), overweight and obese (body mass index [BMI] = 33 +/- 4 kg/m(2)), sedentary (Vo(2)max = 19 +/- 3 ml/kg/min) women underwent one exercise test (Bruce protocol), and 71 of these women underwent a second test (modified Balke protocol). On test 1, 69 (64%) women achieved age-predicted HRmax, 61 (57%) reached an RER>1.10, and 16 (15%) achieved a plateau in Vo(2) (<2 ml/kg/min change). Women who reached age-predicted HRmax and reached an RER of at least 1.10 had a higher peak Vo(2) (p <0.01) than women who did not meet these criteria. There was no difference in the highest V02 obtained between women who did and did not achieve a plateau in Vo(2) during test 1 (p = 0.55). Resting HR, HRmax, and RER were similar between the two tests. On average, peak Vo(2) was higher on the second test (p <0.01). However, Vo(2)max was not different between exercise tests in women who achieved at least two of the three criteria on both tests (n = 24; test 1, 19.4 +/- 3.4; test 2: 19.8 +/- 3.7 ml/kg/min; p = NS). In addition, Vo(2)max was similar between the two exercise tests in 14 women who reached a plateau on the second test but did not reach a plateau on the first test (19.2 +/- 3.3 vs. 19.6 +/- 4.2 ml/kg/min; p = NS). We conclude that achievement of a plateau in Vo(2) is not a necessary criterion for a valid measurement of Vo(2)max in overweight and obese, sedentary, postmenopausal women.

Functional aerobic impairment in adolescents seropositive for HIV: a quasiexperimental analysis

OBJECTIVE

To determine the degree to which cardiorespiratory insufficiency limits physical performance in adolescents seropositive for human immunodeficiency virus (HIV).

DESIGN

Quasiexperimental, case series design.

SETTING

Rehabilitation physiology laboratory.

PARTICIPANTS

Seventeen adolescents (12 women, 5 men; age, 18 +/- 2 yr; weight, 74.7 +/- 19.3 kg; height, 170 +/- 9 cm) with HIV infection (viral load, 22,043 +/- 55,869 copies/mL; CD4 count, 499 +/- 210/mL) who were free of comorbid conditions limiting treadmill performance.

MAIN OUTCOME MEASURES

Spirometric measurements of oxygen uptake and anaerobic threshold obtained from a peak exercise treadmill test using the modified Bruce protocol.

RESULTS

Measured peak oxygen consumption (VO2) was 42% +/- 19% lower than expected (p < .025), suggesting a significant functional aerobic impairment (FAI) or peak VO2 less than 73% of expected values. Peak VO2 was only slightly higher (p < .05) than the oxygen uptake requirements for the most intense activities of daily living (ADL). Anaerobic threshold was only slightly higher (p < .05) than minimum ADL intensities.

CONCLUSIONS

Cardiorespiratory insufficiency and FAI limited the ability to perform even low levels of physical activity in these adolescents with mild HIV seropositivity. Disability identified by quantification of FAI may affect implementation of the American with Disabilities Act and public health policy.