Aerobic Training to Improve Energy Utilization and Antioxidant Capacity in Stroke
Phase: NA
Conditions: Stroke
Sponsor: VA Office of Research and Development

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Aerobic Training to Improve Energy Utilization and Antioxidant Capacity in Stroke 
NCT02043574  
Version 4/16/2019 
 
 
 

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Principal Investigator: Monica C. Serra, PhD 
Sponsor or funding source: Department of Veterans Affairs 
 
Fifteen to 30% of stroke survivors are disabled permanently, resulting in functional dependence and a 
sedentary lifestyle following stroke. Hemiparetic gait, a common disability after stroke, elevates the energy cost 
of ambulatory activity by 1.5-2 fold, but it is currently unknown how chronic stroke affects total daily energy 
expenditure and dietary intake. Altered energy balance following a stroke (expenditure ≠ intake) may result in 
impaired substrate utilization (fat versus carbohydrate oxidation), the production of oxidative stress and 
ultimately decreased cardiovascular and muscular endurance leading to increased fatigue.  
 
This project will compare the effects of chronic treadmill training plus “heart healthy” nutrition modification 
versus whole body stretching plus nutrition on energy balance (dietary intake, resting metabolic rate, and 
exercise and non-exercise energy expenditure) and substrate utilization (measured during an acute exercise 
bout) in older chronic stroke survivors. Furthermore, to examine mechanisms of change, we measured 
changes in markers of oxidative stress before and after the interventions. 
 
Aim 1: To assess the effects of six months of TM+N versus ST+N on total daily energy expenditure (primary 
outcome) and substrate oxidation in chronic stroke survivors.  
Aim 2: To examine the effects of six months of TM+N versus ST+N on systemic oxidative stress in chronic 
stroke survivors.  
 
Experimental Design 
Overview: This project is designed to determine whether treadmill training plus nutrition (TM+N) versus 
stretching plus nutrition (ST+N) (control) will 1) improve energy expenditure and substrate oxidation and 2) 
reduce systemic oxidative stress.  We will study men and women with chronic stroke and stable neurological 
deficits.   
Eligibility criteria include:  
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Age >20 years 
• 
BMI 20-50 kg/m2 
• 
History of stroke at least 6 months prior 
• 
Adequate language and neurocognitive function to safely participate in informed consent, and exercise 
testing and training  
• 
Completion of all conventional inpatient and outpatient physical therapy  
• 
Capable of walking 3 consecutive minutes on a treadmill at 0.1 MPH with handrail support 
• 
Under the care of a primary care medical provider 
• 
Written consent from their doctor that it is safe for them to participant in physical activity. 
Exclusions:  Exclusion criteria include: 
• 
Medical History: a) recent hospitalization (less than 3 months prior to study entry) for severe medical 
disease, b) peripheral arterial disease with vascular claudication, c) orthopedic or chronic pain condition 
restricting exercise, d) pulmonary or renal failure, e) active cancer, f) untreated poorly controlled hypertension 
measured on at least 2 occasions (greater than 160/100) g) type I diabetes mellitus, untreated and / or poorly 
controlled diabetes with fasting blood glucose of greater than 200 and HbA1c greater than 10.0, i) currently 
pregnant 
• 
Neurological history: a) dementia by clinical evaluation b) severe receptive or global aphasia which 
confounds testing and training, operationally defined as unable to follow 2 point commands, c) neurologic 
disorder restricting exercise, such as Parkinson's Syndrome, d) untreated major depression 
• 
Increased alcohol consumption defined as greater than 2 oz. liquor or 2 times 4 oz. glasses of wine or 2 
x 12 oz. cans of beer per day 
• 
Treatment with hormone replacement therapy 
• 
Cardiac history of: a) unstable angina, b) recent (less than 3 months prior to study entry) myocardial 
infarction, congestive heart failure (NYHA category II-IV); c) hemodynamically significant valvular dysfunction 
 

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Subjects will be randomized to TM+N or ST+N (1:1 allocation).  Groups will be matched for sex and race.  All 
subjects will be studied at baseline and after 6 months of TM+N or ST+N. This design will allow us to determine 
total daily energy expenditure, nutritional intake, and substrate oxidation following six months of TM+N and ST+N 
in older stroke survivors.  Further, the design will enable us to determine the effects of TM+N and ST+N on 
systemic oxidative stress.   
 
Metabolic Test by Phase 
 
The experimental design of this study involves 7 phases, completed over 9-10 months (Table 1).  Phase 
1 involves screening and enrollment.  Phase 2 involves baseline testing.  Volunteers then will be randomly 
assigned to TM+N or ST+N (control) (Phase 3).  Phase 4 consists of 2 weeks of weight and dietary stabilization 
prior to baseline research testing.  Phase 5 consists of 2 week testing (post heart healthy).  Phase 6 consists of 
6 months of TM+N or ST+N. After the intervention, subjects will undergo final research testing (Phase 7).  
 
Subject Screening and Enrollment (Phase 1) 
a)      Screening Visits: Eligible volunteers will have the study explained and provide informed consent according 
to the guidelines of the local Institutional Review Board for Human Research.  A fasting blood profile for lipids, 
liver, renal and hematological function will be drawn.  A 12-lead resting electrocardiogram (EKG) will be obtained 
and a medical history and physical examination performed.  Height and weight will be measured using a standard 
physician’s scale.  Seated blood pressures will be measured in duplicate.  Information on demographics and 
family medical history will be recorded.  Subjects will complete the Mini Mental State Exam (MMSE) (60) and 
Center for Epidemiologic Studies Depression Scale (CES-D) questionnaires.  Volunteers also will have a 
screening VO2peak treadmill test as described below.  
 
Table 1: Research Design 
 
Time Duration Research Activity 
Phase 1 
3 weeks 
Screening & Enrollment 
Phase 2 
1 week 
Baseline Testing 
Phase 3 
1 day 
Randomization 
Phase 4 
2 weeks 
Weight & Dietary Stabilization 
Phase 5 
1-2 months 
Metabolic Pre Testing 
Phase 6 
6 months 
TM+N or ST+N 
Phase 7 
1-2 months 
Metabolic Post Testing 
 
Baseline Testing (Phase 2): During this phase, subject will undergo a submaximal treadmill test, blood draw, 
and resting metabolic rate (RMR), as described below. 
 
Randomization (Phase 3): Subjects are randomly assigned to either progressive 6 month treadmill aerobic 
exercise training 3 times per week plus nutritional modification or the reference control of education and stretch 
2 times per week for 6 months plus nutritional modification.   
 
Weight and Dietary Stabilization (Phase 4):  Subjects will meet with a Registered Dietitian 2-3 times weekly 
for 2 weeks to learn “heart healthy” dietary patterns and ensure weight stabilization before metabolic testing.  
Details of the diet are described below.  Prior to metabolic testing, subjects are asked to remain weight stable.   
 
Metabolic Testing (Phase 5):  This testing phase will occur over a period of 1-2 months for each individual.  A 
VO2peak treadmill test, body composition (anthropometrics, DXA, CT) tests, questionnaire completion, and 
functional and strength measures will occur during this phase. Subjects will be weight stabilized throughout the 
metabolic testing.   
 
Treadmill Training plus Nutritional Modification versus Stretch Control plus Nutritional Modification 
(Phase 6):   
 
Treadmill Training 

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Training programs will be individualized based on each participant’s gait capacity and defined by peak heart rate 
(HR max) achieved during a baseline treadmill test. Training will be gradually progressed to a target of 50 minutes 
of exercise at 75-85% of HRR as tolerated by the subject. To assess treatment fidelity, staff will monitor 
progression weekly. A program of home walking equivalent in intensity and duration (3 days/week) to the current 
treadmill intensity and duration (3 days/week) will be recommended. Safety during treadmill training will be 
assured with a parachute style safety harnesses in non-weight bearing mode to support truncal balance, if 
necessary, to reduce the risk of fall. Participants may also use light handrail support. After stroke, the paretic 
arm is often less effective for support.  
 
Stretch Controls: 
Stretch controls will be enrolled in supervised stretching program for 2 days/week for 1 hour sessions. The stretch 
program will focus on basic mobility skills, including balance, sit-to-stand, weight shifting, and leg strength. 
Exercises will be performed in standing, seated, and lying positions. The stretching group will serve as an 
attention control. 
 
Nutritional Modification: All participants will undergo up to 2 weeks nutritional modification counseling in Phase 
4. These nutritional sessions will instruct participants how to consume an isocaloric, “heart healthy” diet with 
adequate protein (<30% of calories as fat, <10% as saturated fat, <2,400 mg sodium, 25 g/d of fiber, and 1.0-
1.2 g/kg/d of lean protein) with a registered dietitian (RD). The RD will collect 24-hour or 3-5 day food records 
during the counseling session to ensure understanding of the dietary prescription. Additionally, compliance will 
be assessed throughout the remainder of the study in Phases 5-7 by periodic food records as deemed necessary 
on an individual basis. Weight will be monitored throughout the study to ensure weight stability. Additional dietary 
instruction will be provided to adjust caloric intake if weight fluctuates ±2%. 
 
Post Intervention Metabolic Testing (Phase 7):  Body weight must be stable  0.25 kg over the two week 
period prior to post-testing.  Subjects will repeat tests outlined in Phase 5.  Metabolic assessments will be 
performed ~36 hrs after the last bout of exercise or stretching and participants will continue to train or stretch 
during the post-testing period, respectively.  
 
Study Procedures 
1. Screening and Baseline Evaluations: Questionnaires to screen for depression and dementia will be 
administered to determine eligibility. Credentialed study staff evaluate all participants to determine whether their 
basic rehabilitation needs have been addressed before study entry. Participants will undergo standard medical 
and neurological examinations to establish medical eligibility and to characterize neurological deficits. Structured 
neurological evaluations may include range of motion tests, manual motor testing, and sensory examinations.  
 
2. Blood and Urine Analyses: We will measure heart disease risk factors, CBC, comprehensive metabolic panel, 
lipid profile, glucose, insulin, free fatty acids, cytokines, oxidative stress, antioxidant capacity, triglycerides, 
lipoprotein lipids, leptin, and adiponectin. A urine pregnancy test is performed prior to the DXA and CT scans, if 
the participant is a woman with child bearing potential.  
 
3. Mobility Function and Motor Control:  
These tests will be administered in Phase 5 and Phase 7. 
30 meter walks: Self-selected and fastest-comfortable floor walking velocity will be determined from 30 meter 
walks with subjects using the same assistive device and/or orthosis as normally used to "walk across the room 
at home." For the 30 meter walks and all walking tests described below, staff will walk beside and spot subjects 
to minimize risk of falls. Walks will be initiated from standing, with completion across an end line 2 meters beyond 
the 30 meter point, to avoid confounding from end of walk slow down. Subjects will be timed during both the self-
selected and fastest comfortable paces.  
6 min walk: Subjects will use the same assistive device and/or orthoses typically used and will be instructed to 
cover as much distance as they can in six minutes over a flat walking surface.  
Timed Up and Go (TUG): Subjects are observed and timed while they rise from a chair, walk 3 meters, turn 
around, walk back, and sit down. A series of 3 TUGs will be performed to assess economy of this simulated 
ADL. An assistive device and/or orthoses may be used. 

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4. Treadmill Tests:  
Peak: Treadmill tests will start at a self-selected pace, and will be advanced by adequate increments according 
to tolerance, perceived exertion, and medically credentialed clinician rating of gait stability. This clinically 
supervised test will determine treadmill gait safety, functional eligibility to participate (must walk 3 minutes at 0.1 
MPH with handrail support), cardiopulmonary response to strenuous exertion defining exercise tolerance and 
safety, and allow us to pre-select testing parameters for subsequent constant velocity peak effort graded 
treadmill testing. Belt safety harness will be worn with a spotter behind the subject, and handrail support will be 
used at all times. Peak exercise tests will evaluate the cardiopulmonary response to exertion, under clinician 
supervision with continuous vital signs and EKG monitoring. Tests will be terminated at the subject’s request, 
and based on American College of Sports Medicine criterion. Baseline peak test is reviewed by a cardiologist as 
part of our quality assurance program.  The peak fitness test will be completed during Phase 1, Phase 5, and 
Phase 7. 
 
Submaximal Treadmill Test: After a 12 hour fast, economy of hemiparetic gait will be measured using open circuit 
spirometry during a standard constant load submaximal effort treadmill walking task at a pre-established gait 
velocity (60-80% of self-selected floor walking velocity). This slower walking velocity is selected because 
untrained subjects with stroke usually cannot maintain their self-selected walking pace, precluding steady state 
measures of oxygen consumption that defines gait economy. The mean rate of VO2 will be calculated based on 
the final 3 minutes of a 10-minute walk under steady state oxygen consumption conditions. Subjects not 
achieving a plateau in VO2 will be re-tested at a lower velocity on a different date to eliminate potential 
confounding effects of fatigue on testing. This test will be completed before (Phase 3) and after (Phase 5) the 
Dietary Education (Phase 4), as well as in Phase 7 after the 6-month exercise or stretching interventions. 
 
5. Energy Expenditure  
Resting Metabolic Rate (RMR) will be measured using the ventilated hood technique while subjects lie quietly in 
bed for 30-45 mins under a clear plastic hood with expired air collected through a one-way valve (Weir JB deV. 
RMR will be measured at rest in Phase 3, 5 and 7. 
 
Activity Monitoring: Subjects will answer activity questionnaires. They will wear an accelerometer activity monitor 
on their belt for 5 to 7 days to determine caloric expenditure in daily activities in Phase 5 and Phase 7.  
 
6. Dietary Intake Assessment: A Registered Dietitian will instruct subjects on how to complete a 3-5-day food 
record or collect 24 hour dietary recalls that will be analyzed and used as measures of dietary habits. Dietary 
assessment will occur in at the beginning and end of Phase 4, as well as in Phase 7 following the 6-month 
interventions.  
 
Statistical Analysis and Expected Results: Data from the study will be entered into a data set and validated 
by the study PI. Initially, analyses will be adjusted for site to determine whether site is a significant covariate to 
our outcomes of interest; however, if site is not significant, it will be dropped from further analyses.  Descriptive 
statistics will be calculated for all variables using SAS version 9.3 (SAS Institute, Cary, N.C.) and the R statistical 
package.  Exploratory data analyses will be performed to check the data for extreme values and to determine 
the distribution of values.  Extreme values will be verified against original source documents.  When necessary, 
data will be transformed to normality using appropriate transforms.  A two-tailed P <0.05 will considered indicative 
of a significant result.  In addition to P values, 95% confidence intervals will be reported. The primary variable of 
interest to test the main hypotheses includes: 1) total daily energy expenditure measured by RMR (indirect 
calorimetry) + energy expenditure during activity (accelerometry). Secondary variables include substrate 
oxidation measured as fat and glucose oxidation during submaximal exercise, systemic (plasma) oxidative 
stress, VO2peak. 
 
Statistical Analysis Plan 
Primary Aim: To assess the effects of six months of TM+N versus ST+N on total daily energy expenditure 
(primary outcome) and substrate oxidation in chronic stroke survivors.   

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Expected Results: We anticipate that TM+N will result in significant changes in RMR and energy 
expenditure during activity, as well as greater reliance on fat at resting and an improved ability to switch from fat 
to carbohydrate utilization during submaximal exercise and after a mixed meal challenge.   
 
Aim 2: To examine the effects of six months of TM+N versus ST+N on systemic and tissue inflammation and 
oxidative stress and antioxidant capacity in chronic stroke survivors.   
 
Expected Results: We expect that TM+N will result in decreased oxidative stress in the circulation.   
 
The change (post-pre) value of the energy expenditure and substrate oxidation outcomes, along with measures 
of oxidative stress and antioxidant capacity will be the dependent (outcome) variables in a series of ANOVAs 
(one for each outcome variable).  Independent variables will include the initial value of the outcome variable, 
group assignment, along with the subject’s age and BMI, and if needed (i.e. if there are differences between the 
exercise and stretching subjects) medications and medical conditions other than presence of stroke.  Baseline 
dietary intake will be treated as covariates.  These analyses will tell us if there is a differential effect of exercise 
versus stretch control with nutritional modification on the outcome measures.   
 
 

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