Robert G. Haennel

SenseWear Armband and Stroke: Validity of Energy Expenditure and Step Count Measurement during Walking

The purpose of this study was to test the validity of the SenseWear Pro Armband (SWA) for the measurement of energy expenditure (EE) and step count against a criterion in persons with stroke. Twelve participants with chronic stroke (mean age 64.2 ± 10.4 years; mean gait speed 0.67 ± 0.25 m/sec) completed two trials of a six-minute walk test, while wearing a SenseWear Armband (SWA) on each arm and being continuously monitored using a portable metabolic cart. Agreement between estimates of energy expenditure from the SWA and the metabolic cart was fair for the armband on the hemiplegic arm (intraclass correlation cefficient (ICC) = 0.586) and good for the armband on the unaffected arm (ICC = 0.702). Agreement between the SWA estimate of step count, and step count as measured by the Step Activity Monitor was poor (ICC < 0.352), with significant underestimation by the SWA. Our results show that, for these moderately impaired persons with stroke, the SWA should be used with caution for the measurement of energy expenditure and should not be used to measure step count.

Effects of hydraulic circuit training on cardiovascular function.

The effect of hydraulic circuit training (HCT) on cardiovascular (CV) function was assessed in 32 healthy middle-aged males (X age = 42.2 +/- 2.1 yr). Maximal aerobic power (VO2max), with simultaneous measurement of stroke volume (SV) and cardiac output (CO), by impedance cardiography, was assessed pre- and post-training. Subjects were randomly assigned to a nonexercising control group, a cycle training group (cycle), or one of the two HCT groups. Training groups participated in a 9 wk program, 3 d.wk-1. Subjects assigned to HCT exercised on a 9 station circuit, completing 3 circuits.d-1. Each circuit consisted of three 20 s work intervals at each station with a 1:1 work:rest ratio. One HCT group (HCTmax) completed the maximal repetitions possible (RM) during each work interval. The other HCT group (HCTsub) exercised at 70-85% of RM. Following training VO2max (ml.kg-1 min-1) was significantly increased in all training groups (18.0, 12.5, and 11.3% for cycle, HCTsub, and HCTmax groups, respectively; P less than 0.05). The increase in VO2max observed in the cycle group was significantly greater than that recorded by the two HCT groups (P less than 0.05). For all three training groups, the increase in VO2max was associated with increases in SVmax and COmax (P less than 0.05 for both). These findings suggest that both maximal and submaximal HCT programs can elicit improvements in cardiovascular fitness.

Cardiac Reserve and Pulmonary Gas Exchange Kinetics in Patients With Stroke

Background and Purpose— Cardiovascular and pulmonary factors contributing to impaired peak oxygen uptake (&OV0312;O2) in patients with stroke (SP) are not well known. We assessed cardiovascular function, pulmonary gas exchange, and ventilation in SP and healthy age, gender, and activity-matched control subjects. Methods— Ten hemiparetic SP and 10 control subjects were enrolled. Subjects completed cycle ergometry testing to assess peak and reserve &OV0312;O2, carbon dioxide production, ventilation (tidal volume; breathing frequency; minute ventilation), and cardiac output. &OV0312;O2, carbon dioxide production, and minute ventilation were measured throughout peak exercise recovery (off-kinetics) and at exercise onset (on-kinetics) along with heart rate during low-level exercise. Results— Peak &OV0312;O2 was 43% lower (P<0.001) in SP secondary to reduced peak and reserve cardiac output and minute ventilation. The impaired cardiac output reserve (P<0.001) was due to a 34% lower heart rate reserve (P=0.001). The impaired minute ventilation reserve (P=0.013) was due to a 41% lower tidal volume reserve (P=0.009). Stroke volume and breathing frequency reserve were preserved. &OV0312;O2 off-kinetics were 29% slower in SP (P<0.001) and related to peak &OV0312;O2 (R=−0.72, P<0.001) and peak cardiac output (R=−0.75, P<0.001) for the study group. Additionally, carbon dioxide production (P=0.016) and minute ventilation (P=0.023) off-kinetics were prolonged in SP. &OV0312;O2 on-kinetics were 29% slower (P=0.031) during low-level exercise in SP. Conclusions— The impaired peak &OV0312;O2 in SP is secondary to a decline in peak and reserve cardiac output and ventilation. Prolonged &OV0312;O2 kinetics in SP are associated in part with deconditioning and may be mediated by reduced O2 availability and/or the rate of muscle O2 use.

Effect of acute high-intensity interval exercise on postexercise biventricular function in mild heart failure

We studied the acute effect of high-intensity interval exercise on biventricular function using cardiac magnetic resonance imaging in nine patients [age: 49 ± 16 yr; left ventricular (LV) ejection fraction (EF): 35.8 ± 7.2%] with nonischemic mild heart failure (HF). We hypothesized that a significant impairment in the immediate postexercise end-systolic volume (ESV) and end-diastolic volume (EDV) would contribute to a reduction in EF. We found that immediately following acute high-intensity interval exercise, LV ESV decreased by 6% and LV systolic annular velocity increased by 21% (both P < 0.05). Thirty minutes following exercise (+30 min), there was an absolute increase in LV EF of 2.4% (P < 0.05). Measures of preload, left atrial volume and LV EDV, were reduced immediately following exercise. Similar responses were observed for right ventricular volumes. Early filling velocity, filling rate, and diastolic annular velocity remained unchanged, while LV untwisting rate increased 24% immediately following exercise (P < 0.05) and remained 18% above baseline at +30 min (P < 0.05). The major novel findings of this investigation are 1) that acute high-intensity interval exercise decreases the immediate postexercise LV ESV and increases LV EF at +30 min in patients with mild HF, and this is associated with a reduction in LV afterload and maintenance of contractility, and 2) that despite a reduction in left atrial volume and LV EDV immediately postexercise, diastolic function is preserved and may be modulated by enhanced LV peak untwisting rate. Acute high-intensity interval exercise does not impair postexercise biventricular function in patients with nonischemic mild HF.

Use of the Continuous Scale Physical Functional Performance Test in Stroke Survivors

OBJECTIVE To (1) determine the feasibility of the continuous scale physical functional performance 10-item test (CS-PFP10) for the measurement of physical function in stroke survivors, (2) characterize physical functional performance of stroke survivors and their matched controls, and (3) explore the associations among physical functional performance, ambulatory activity, and peak oxygen uptake (VO2peak). DESIGN Case control. SETTING University research setting. PARTICIPANTS Ten participants with stroke and 10 healthy controls matched for age, sex, and physical activity. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The CS-PFP10 test was used to measure functional ability. The test requires performance of 10 serial tasks that range from low to high difficulty. The step activity monitor was used to measure absolute ambulatory activity and was reported as the average number of steps a day over a 4-day period. VO2peak was determined using a metabolic cart and a recumbent cycle ergometer. RESULTS Stroke survivors scored lower than healthy controls on all individual tasks, domains, and the total score on the CS-PFP10. Higher VO2peak was associated with higher total scores on the CS-PFP10 in both stroke survivors and controls. In stroke survivors, lower levels of impairment (as indicated by the Chedoke-McMaster stroke assessment) were associated with higher total CS-PFP10 scores. CONCLUSIONS The CS-PFP10 is a measure of physical performance that is feasible to use with ambulatory participants with stroke. Future investigations with people with stroke should explore the ability of the CS-PFP10 to provide meaningful information about change in CS-PFP10 subscales with interventions that target items on the subscales, such as balance or upper extremity strength.

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

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

Oxygen uptake kinetics: associations with ambulatory activity and physical functional performance in stroke survivors.

OBJECTIVE To explore the associations amongst the on-and-off kinetics time constants, ambulatory activity outcomes, and physical functional performance in stroke survivors. DESIGN Cross-sectional, case control study. SUBJECTS Ten stroke survivors (time since stroke: mean 7.5 years (standard deviation 8.3); gender: 4 males, 6 females) and 10 control subjects matched for age and physical activity level. METHODS Oxygen uptake kinetics (on-and-off kinetics) were measured using a submaximal exercise test with a recumbent cycle. The continuous-scale physical functional performance test was used to measure functional ability. Ambulatory activity outcomes including steps per day, number of activity bouts and length of activity bouts were measured using a Step Activity Monitor. RESULTS AND CONCLUSION Shorter activity bouts were significantly associated with longer off-kinetics time constants in stroke survivors (or longer time to recover from an exercise bout). Future research may test the effect of activity interventions designed to increase the length of activity bouts on-kinetics outcomes and functional ability.

Exercise prescription for patients with pacemakers.

When developing an exercise program for pacemaker patients, basic information about the pacemaker must be understood. Atrial, ventricular, and dual-chamber devices can produce varying exercise responses and impact the exercise prescription. The type of rate adaptive sensor the pacemaker has will affect the nature of heart rate response, and therefore, must be taken into account when prescribing exercise. While rate modulation is used with most chronotropically incompetent patients, individuals with VVI pacemakers will also benefit from regular exercise. Although the value of exercise testing pacemaker-dependent patients for ECG interpretation may be limited, it is useful in determining exercise capacity and ensuring proper pacemaker function. Participation in a supervised exercise training program can greatly enhance the follow-up and management of pacemaker-dependent patients as well as afford them the opportunity to experience the physical and psychologic benefits typically associated with cardiac rehabilitation.

Exercise training improves aerobic capacity, muscle strength, and quality of life in renal transplant recipients

Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and strength training (EST, n = 16) versus usual care (UC, n = 15) on peak aerobic capicity, cardiovascular and skeletal muscle function, CVD risk profile, and quality of life (QOL) in RTR (55 ± 13 years). Peak aerobic capacity and exercise hemodynamics, arterial compliance, 24-h blood pressure, muscle strength, lean body mass, CVD risk score, and QOL were assessed before and after 12 weeks. The change in peak aerobic capacity (EST: 2.6 ± 3.1 vs. UC: -0.5 ± 2.5 mL/(kg·min)), cardiac output (EST: 1.7 ± 2.6 vs. UC: -0.01 ± 0.8 L/min), leg press (EST: 48.7 ± 34.1 vs. UC: -10.5 ± 37.7 kg) and leg extension strength (EST: 9.5 ± 10.3 vs. UC: 0.65 ± 5.5 kg) improved significantly after EST compared with UC. The overall change in QOL improved significantly after 12 weeks of EST compared with UC. No significant difference was found between groups for lean body mass, arterial compliance, 24-h blood pressure or CVD risk score. Supervised EST is an effective intervention to improve peak exercise aerobic capacity and cardiac output, muscle strength and QOL in clinically stable RTR.

Impact of Cardiac Rehabilitation on the Ability of Elderly Cardiac Patients to Perform Common Household Tasks

PURPOSE The consequences of coronary artery disease may significantly limit functional independence of elderly patients. While cardiac rehabilitation (CR) exercise programs have been shown to improve health outcomes such as exercise capacity, little is known about the impact such programs have on daily functional abilities. The purpose of this study was to determine the impact of CR on ability of elderly patients to perform common household tasks. METHODS Twenty-two postmyocardial infarction patients (10 women and 12 men; age 75 ± 6.3 years) were studied. Patients were tested pre-CR and post-CR. Physical function (PF) was assessed using the Continuous Scale Physical Function Performance 10 test battery, which includes 10 everyday tasks that progress from easy (personal tasks) to moderate (household tasks) to difficult (mobility tasks). Self-reported PF was measured using the Medical Outcomes Survey Short Form 36-Item questionnaire. RESULTS Post-CR, the global Continuous Scale Physical Function Performance 10 score increased significantly (57 + 12 vs 50 ± 16; P = .002). Prior to CR, 7 patients scored at or above the threshold for independent living, as defined by a global score of 57 or more units; however, post-CR, 12 patients scored above the threshold. There was no change in self-reported PF, post-CR. CONCLUSIONS A 20-session exercise-based CR program significantly enhanced elderly patient ability to live independently by improving ability to perform common household tasks.