Effects of a Walking Program and Inspiratory Muscle Training on Individuals With Chronic Heart Failure

• SF-36 Quality of Life questionnaire [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  The SF-36 quality of life questionnaire (short form) will be used.
  
  
• Minnesota Living with Heart Failure Questionnaire [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  This questionnaire includes 21 questions which ask how much the heart condition affected the patient's life during the past month (4 weeks).
  
  

• Heart rate variability [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  A minimum of ten participants (5 in each group) will be selected randomly to record their 24-hour heart rate variability at home and return the unit at their next visit.
  
  
• Physical Activity [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  Each subject will be given a pedometer to record his/her step counts every day. They will also wear a heart rate monitor while they walk. They will record their steps and average heart rate in the walking log.
  
  
• respiratory muscle strength [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  The inspiratory muscle strength will be measured in the unit of cmH2O by the Respiratory Muscle meter (Micro Direct).
  
  
• Six-minute walk test distance [ Time Frame: 6-week training ] [ Designated as safety issue: No ]
  The six-minute walk test is a measure of cardiovascular endurance which measures how far a person can walk in 6 minutes. This test will be conducted twice respectively at pre-training and also post-training to account for potential learning effect.
  
  

Participants will be recruited from the heart failure clinic at the St. Paul Hospital of UT Southwestern University in Dallas, TX, which is across the street from Texas Woman's University - Dallas Center. Flyers will be distributed to cardiologist there and posted on their bulletins. A research seminar reviewing the literature of inspiratory muscle training in patients with heart failure was given during the planning stage of the project, and those cardiologists were aware of the scope of the study and its inclusion and exclusion criteria of research participants. Potential research participants could call the research team for further information.

Participants will come to the first session where a history interview will be conducted to gather demographic data including age, race/ethnicity, and gender. We will measure height and weight and collect baseline data for the a) 6 minute walk test, b) respiratory muscle strength, c) comfortable walking speed, d) grip strength, and e) single limb stance time will be taken. Participants will also fill complete two quality of life questionnaires (SF-36, Minnesota Living with Heart Failure Questionnaire.

Each participant will be randomly assigned to one of two groups: a) a walking group with a high-intensity Inspiratory Muscle Training (IMT) program, OR a walking program with a sham IMT program. The Sham group will be trained at a low intensity and low repetitions. The training threshold for Experimental IMT arm will be set at 60% of PImax (high-intensity respiratory muscle training). The PImax will be adjusted weekly, nose clip used to ensure participant breathes completely through the mouth. Frequency: 5x/week; 1x/day preferred. 6 Interval Levels: (6 inspiratory efforts in each level): (1) 60s rest interval; (2) 45s rest interval; (3) 30s rest interval; (4) 15s rest interval; (5)10s rest interval; (6) 5s rest interval, trained to exhaustion. The sham IMT intensity will be set at fixed 15% PImax. Research participants will be blinded on the group assigned. The time commitment for their IMT training is about 15-20 minutes. Individuals from both research groups will come in to the School of Physical Therapy at Dallas Center once a week for 15 to 20 minutes to be tested and possibly re-adjust the IMT training intensity on the breathing device and to allow us to document their weekly step count.

Each participant will be given a pedometer and heart rate monitor so they can track their step counts and walking heart rate during the study. The walking program will consist of walking every day at an intensity of "hard" to "somewhat hard" on the Rating of Perceived Exertion (RPE) scale. Participants will begin walking at least 15 minutes twice a day for 7 days a week and eventually progress to 45-50 minutes a day by the end of the six weeks.

Depending on the availability of holter monitor heart rate recorder, a minimum of ten participants (5 in each group) will be selected randomly to record their 24-hour heart rate variability at home and return the unit at their next visit.