Effects of a Walking Program and Inspiratory Muscle Training in Individuals With Chronic Heart Failure
Condition: Heart Failure NYHA Class II; Heart Failure NYHA Class III
MeSH terms: Respiratory Aspiration; Heart Failure
Study type: Interventional

Summary: 
      Individuals with chronic heart failure need a "safe and effective" exercise program that
      could enhance their quality of life. In this study, we examined whether an experimental
      exercise program of autonomous walking and high-intensity Inspiratory Muscle Training (IMT)
      could result in better effects on respiratory muscle strength (PImax), cardiovascular
      endurance, quality of life, and physical activity, when compared to autonomous walking and
      "sham" IMT program, in adults with chronic heart failure.
    

Detailed description: 
      Participants were recruited from the outpatient heart failure transitional care clinic at the
      Presbyterian Hospital of Dallas and other local heart failure support groups. Flyers were
      distributed to cardiologists, nurse practitioners, and local heart failure support groups in
      the Dallas/Ft Worth area. Cardiologists and nurse practitioners were aware of the scope of
      the study and its inclusion and exclusion criteria of research participants. Potential
      research participants could then call the research team for further information.

      Participants came to our facility for the initial evaluation session, where a history
      interview was conducted to gather demographic data, such as age, gender, height, weight,
      race/ethnicity, and past medical/surgical history. The following baseline data were then
      collected: a) two trials of the six-minute walk test, b) respiratory muscle strength
      indicated by maximal inspiratory pressure (PImax), and two quality of life questionnaires.
      During the walk test, heart rate and heart rhythms were continuously monitored via a holter
      monitor. During the rest breaks, research participants filled out two quality of life
      questionnaires (SF-36, Minnesota Living with Heart Failure Questionnaire).

      Each participant was randomly assigned to one of the two groups: a) the autonomous walking
      program with a high-intensity Inspiratory Muscle Training (IMT) program, or b) the autonomous
      walking program with a sham IMT. The training threshold for the experimental IMT group was
      trained at 60%PImax which was reassessed at weekly follow ups. The frequency of training was
      5x/week (1x/day preferred) for 6 interval levels at each session (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
      intensity of sham IMT was set at fixed 15% PImax. Research participants were blinded to the
      group assignment. The time commitment for IMT was about 15-20 minutes a session per day at
      home. Weekly follow up was conducted at the School of Physical Therapy in Dallas to reassess
      PImax, collect the log of daily step count, and discuss about the walking program. Every
      participant was given a breathing device for inspiratory muscle training.

      Each participant was given a pedometer and a heart rate monitor to track their daily step
      counts and heart rate during the walking session. The walking program consisted of walking
      daily at an intensity of "somewhat hard" to "hard" on the Borg's Rating of Perceived Exertion
      (RPE) scale. Participants were encouraged to walk 10 to 15 minutes, once to twice a day
      initially, then progressed to about 45-50 minutes a day by week six, if they could tolerate.
      At the end of 6 weeks, these participants returned to our facility for the final evaluation
      session.
    

Intervention name(s): High-intensity IMT plus walking; Low-intensity IMT plus walking
Intervention type(s): Behavioral; Behavioral
Intervention description(s): The IMT intensity was set at 60% of PImax which was reassessed weekly. Frequency: 5x/week; 1x/day preferred. 6 Interval Levels: (6 efforts at 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.
For the walking program, it was the same as the one for the control group.; The IMT training was 3 sets of 10 repetitions, or when the participant felt tired. Participants returned to our facility every week to reassess PImax.
For the walking program, each participant was given a pedometer and a heart rate monitor to track daily step counts and heart rate. The walking program consisted of walking every day at an intensity of "somewhat hard" to "hard" on the Borg's Rating of Perceived Exertion scale. Participants began at least 10 to 15 minutes, once to twice a day, for 7 days a week, and eventually progressed to 45-50 minutes a day by the end of the six weeks, if they could tolerate.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Heart failure; inspiratory muscle training; physical activity