The purpose of this protocol is to begin an exercise program combined with behavioral counseling for patients who are hospitalized with a cystic fibrosis exacerbation. The exercise program will begin during the hospital stay. Beginning an exercise program during this period of reduced mobility and isolation may be an ideal time to deliver a structured exercise prescription along with a behavioral program to promote long-term adherence to exercise (structured physical activity) . Hospitalized patients have an acute awareness that their lung function is declining and may be more motivated and open to changing their behavior and adding exercise to their treatment regimen.

During the hospitalization (T0 to T1; Figure 1, next page), participants will perform supervised exercise 6 days/wk. On each of these days, there will be a 5-10 min warm up consisting of low intensity execises for lower and upper exermity muscles. The total time per week will be between 2.5 and 3.5 hours.

Three days/wk will consist of aerobic exercise ("frequency"). The various "modes (types)" for this exercise include 1) overground ambulation (including stairs), 2) treadmill ambulation, 3) stationary cycling, or 4) repetitive body-weight exercises (e.g., "jumping jacks"). The "time (duration)" of these sessions will be 20-30 min/day. The "intensity" will be moderate (40-60% of heart rate reserve and/or perceived dyspnea/exertion of 3-5) to vigogous (60-85% of heart rate reserve and/or perceived dyspnea/exertion of 6-8). Participants will be given a HR monitor and specific "target" HR ranges based on their resting HR in standing and their age predicted maximal HR (NOTE: maximal exercise testing will not be performed); they will also be familiarized and instructed in use of the Borg CR10 scale to rate perceived dyspnea/exertion Participants should be able to "talk comfortably" during moderate intensity exercise, while talking should be "somewhat challenging" during vigorous efforts; HR, as well as perceived exertion/dyspnea and "talk test" will be monitored throughout each supervised session by trained personnel.

On alternate days, participants will perform supervised resistance exercise training (3 days/wk; "frequency"). The various "modes (types)" for this exercise include 1) body-weight exercises (e.g., lunges, squats, jumping, situps, pushups) and/or 2) resistance bands and dumbbells; exercises will target upper extremity, trunk/core, and lower extremity muscles (NOTE: specific inspiratory muscle training will not be performed). The "intensity" of these exercises will be at approximately 12-15 repetition max (that is, on the 3rd set of an exercise, the participant should have difficulty performing more than 12-15 quality (good form) repetitions of the exercise. An appropriate number of exercises will be selected such that the exercise "duration (time)" will be 20-30 min/day.

Inclusion Criteria:

1. Confirmed diagnosis of CF
2. 18 years old or older
3. Current pulmonary exacerbation with planned UAB hospitalization for at least 10 days
4. Willing to participate in a regular, ongoing exercise program
5. Access to broadband internet

Exclusion Criteria:

1. Currently exercising more than 60 min/week
2. Massive hemoptysis or pneumothorax in past 3 months
3. Neuromusculoskeletal impairments that preclude exercise