The study will evaluate the utility of hypoxic exercise training to improve cardiovascular and metabolic health among obese breast cancer survivors. While participants exercise, a lower fraction of inspired oxygen will be used to simulate a higher altitude. This approach removes the mechanical strain needed to sustain moderate-to-vigorous exercise intensity which is believed to support exercise tolerance. Participants are randomized to either the treatment (walking+simulated-altitude) or control (walking under normoxic conditions).
Cancer survivors have a two-fold greater risk of having one or more functional limitations compared to those without a history of cancer. Though exercise interventions in breast cancer survivors exist, a large portion of women (61%) exhibit some form of lower-body dysfunction that severely restricts participation in physical activity and exercise. Both physical and emotional well-being are negatively affected by the combination of increased adiposity, orthopedic problems and muscle weakness, thus reinforcing a cycle of physical inactivity. For these reasons, obese breast cancer survivors with walking limitations are faced with a barrier that greatly increases the difficulty of meeting prescribed exercise guidelines (≥150 weekly minutes of moderate-to-vigorous intensity exercise). Though previous investigations have demonstrated the safety and benefits of exercise+simulated altitude to improve body fat, physical endurance and insulin sensitivity, results have been limited to non-cancer participants only. Given the comorbidities common to breast cancer survivors, specifically, heart disease risk, lower body joint problems, low aerobic capacity, and fatigue, further research is needed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
15
Participants will walk on a treadmill for up to 50 minutes at a 16% oxygen level (administered via exercise mask), which is similar in altitude to Flagstaff, AZ. The progression of exercise training will be based on a varying percents of heart rate reserve.
Participants will walk on a treadmill for up to 50 minutes.The progression of exercise training will be based on a varying percents of heart rate reserve.
University of Alabama at Birmingham
Birmingham, Alabama, United States
Determine the feasibility of an 8 week exercise intervention comparing walking+simulated-altitude to walking (control) based on retention.
number of participants completing the 8 week session
Time frame: baseline to 8 weeks
Determine the feasibility of an 8 week exercise intervention comparing walking+simulated-altitude to walking (control) based on adherence to exercise compliance.
mean compliance among all participantswith exercise prescription
Time frame: baseline to 8 weeks
Determine the feasibility of an 8 week exercise intervention comparing walking+simulated-altitude to walking (control) based on number of adverse events.
Number of adverse events in each group
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by a 6 minute walk.
6 minute walk test, a valid and reliable tool in cancer survivors will be used to evaluate cardiovascular health and mobility. Total distance (in meters) covered over the duration of 6 minutes will be recorded.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by the cardiorespiratory fitness.
Cardiorespiratory fitness, will be measured by indirect calorimetry during a graded walking test on a treadmill to estimate peak aerobic capacity.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by arterial elasticity.
Arterial elasticity, will be measured by local pulse contour analyses (HDI/Pulse Wave), A non-invasive procedure based on a modified Windkessel model which permits the evaluation of vascular health.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by resting heart rate variability.
Heart rate variability, will be determined by R-to-R interval variations in heart rate, used to index sympatho-vagal balance.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by the fasting glucose.
Typically, a "normal" blood sugar level is identified by experts as anything less than 100 mg/dL after a period of fasting.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by C-reactive protein (mg/L) serum assays.
Serum assays, will be measured following an overnight to evaluate metabolic and cardiovascular health. Standards practices will be implemented.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by tumor-necrosis factor-alpha (pg/mL) assays.
Serum assays, will be measured following an overnight to evaluate metabolic and cardiovascular health. Standards practices will be implemented.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by interleukin-6 (pg/mL) serum assays.
Serum assays, will be measured following an overnight to evaluate metabolic and cardiovascular health. Standards practices will be implemented.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by interleukin-10 (pg/mL) serum assays.
Serum assays, will be measured following an overnight to evaluate metabolic and cardiovascular health. Standards practices will be implemented.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by body composition (% body fat).
Body composition, will be measured by dual-energy X-ray absorptiometry during which participants will be scanned while lying supine in light clothing with their arms at their sides.
Time frame: baseline to 8 weeks
The effect sizes for walking+simulated-altitude and walking (control) as measured by free-living physical activity.
Free-living physical activity, will be measured by a triaxial accelerometer (e.g., Actigraph GT3X). Participants will wear the accelerometer on the hip of their non-dominant side during waking periods and around the wrist when sleeping according to a previously published protocol.
Time frame: baseline to 8 weeks
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