Outline the benefits of an exercise programme for people with cystic fibrosis, and discuss the factors which may influence exercise compliance for the condition. The discussion should be supported by references to the literature.
Introduction
Cystic fibrosis (CF) also known as mucoviscidosis, is the most common life-limiting autosomal recessively inherited disease in Caucasian populations, with a carrier rate of 1 in 25 and an incidence of 1 in 2500 live births in the USA (The Cystic Fibrosis Trust's Clinical Standards and Accreditation Group. 2001). Ireland has an exceptionally large rate of cystic fibrosis suffers and it is the most common life-threatening inherited disease in the country. Approximately 1 in 19 people are carriers of the CF gene in Ireland and where two carriers parent a child together; there is a 1 in 4 chance of the baby being born with Cystic Fibrosis. (The cystic fibrosis association of Ireland, 2010) The disease is responsible for premature mortality with the average life expectancy estimated at 31 years.
Cystic Fibrosis impacts the body's glands, causing damage to multiple organs including the lungs, pancreas, the digestive tract and the reproductive system. A characteristic of the disease is a presence of a thick sticky mucus in the respiratory airways that makes it difficult for the sufferer to get adequate air into and out of the lungs. Bacteria thrive in the accumulated mucus and cause patients to suffer infections. Sufferers are particularly susceptible to Pseudomonas aeruginosa, a bacterium which causes infection due to a handicap in the body's defences. Gradually the lung tissue becomes scarred (fibrotic) which makes it difficult to inflate the lungs. This increases the work of breathing in combination with trying to move air passed the clogged airways. The cause of cystic fibrosis can be attributed to several genetic defects that lead to the production of a flawed version of the protein named cystic fibrosis transmembrane conductance regulator (CFTR) (Sherwood, 2008)
Benefits of the exercise programme
This essay aims to provide the background and rationale for the implementation of exercise and physical activity in patients with cystic fibrosis. There is evidence to support the prescription of aerobic, anaerobic and strength training exercises for sufferers of cystic fibrosis.
Exercise is recommended for adults with cystic fibrosis as it supports airway clearance, decreases cardiovascular risk factors associated with inactivity (Marshall et al, 2004) and has been related to enhancement in quality of life for adults. (Silva et al, 2008) A number of studies have experienced an increase in peak exercise capacity in response to programmes of aerobic exercise training. Other studies have detailed increases in strength, increased sputum expectoration, decreased breathlessness and improved ability to perform activities of daily living all as a result of exercise training. Furthermore data obtained from exercise studies has suggests the preservation or improvement of lung volume. (Morris et al, 2004)
A study by Webb et al. (2004) (n=48) observed a training effect, measured by a reduction in lactate levels (p<0.05) and heart rate (p<0.05) which was achieved with unsupervised individualised home exercise programs in adults with cystic fibrosis. They further observed a benefit to pulmonary function and concluded their findings suggest that exercise programmes should be encouraged as an important component of care in cystic fibrosis
As the onset of cystic fibrosis and subsequent diagnosis usually occurs in childhood, much of the relevant literature pertaining to exercise and the disease is amongst a young population.
There is much literature supporting the use of exercise in paediatric patients with cystic fibrosis.
A study by Kelsey et al (1992) presented a significant correlation between aerobic fitness and survival. The authors also suggested that peak VO2 could be used as an independent predictor of survival. A similar study by Leblanc et al. (2005) confirmed Kelsey's findings and further reported that sufferers with a VO2 peak of more than 45 ml kg 1min 1 had an improved survival compared to those with a VO2 peak less than 32 ml kg 1min 1. Furthermore a study by Kimpen et al. (2003) displayed a longitudinal relationship between changes in nutritional status, lung function, and VO2peak in children with CF.
Anaerobic exercise can also be valuable for sufferers of CF. Research conducted by Kimpen et al. (2003) and Wexler et al. (2005) used a training program of standard bouts of short-duration exercise resulted in improvements in aerobic as well as anaerobic measures and health-related quality of life in children with CF. Strength training is also of benefit to CF sufferers as high quality studies by Hovell et al. (2004) and Selvadurai et al. (2002) proved that strength gains are achievable in paediatric patients with CF.
A number of systematic reviews have been carried out that look at a number of published articles in the area of CF and exercise. Reviews by Bradley & Moran. (2002), Van Doorn. (2009) and Wilkes et al. (2009) are the most recent and accurate in the area of CF and exercise. (See Appendix) Van Doorns review (n=4) is perhaps the most useful as it was published in 2009 and their included papers cover several exercise modalities and different severities of the disease. She concluded that there was evidence to support that both aerobic and strength training and it can positively impact pulmonary function, aerobic fitness, and strength. However she also stated that there was a need for more randomised controlled trials in this area.
Components of the most effective exercise interventions for this condition
Exercise response is extremely variable in patients with CF because it is related to the severity of the disease which significantly modulates exercise capacity. As such the type of exercise prescribed should be based on severity of condition, objective testing results and include adequate monitoring. The patient should be evaluated for exercise tolerance, physical limitations and a requirement for supplemental oxygen before they take part in exercise. Tests that may prove useful are timed distance walk tests, incremental submaximal, or maximal exercise tests or ramp test protocols and submaximal steady state constant workload tests. Ideally, a program of physical activity should combine endurance and strength-training exercises for both the upper and lower body. (Webb et al, 2000)
Modality
There is evidence to support the prescription of aerobic, anaerobic and strength training exercises. Weight bearing and body weight exercised should be administered where possible. (See appendix for program). The program should be progressively designed. The progression can be achieved by manipulating volume, frequency and intensity and based on objective testing results. (LeMura et al, 2004)
Intensity
The prescribed exercises should enable the participant to exercise in the region of the middle intensities. Between 50 - 70% of the individuals maximum capacity is usually prescribed for cardiovascular benefits to occur. As CF patients can be limited by ventilatory factors before their heart rate reaches its maximum, the Karvonen formula cannot be used accurately. Instead the exercise must be prescribed based on the patients measured maximum. The target heart rates should be below the point at which desaturation was observed during the exercise test. If the patient experiences desaturation at the onset of exercise or prior to reaching 120 beats per minute supplemental oxygen can be used to keep the SaO2 above 90% and allow exercise at 120+ beats per minute.
For resistance training a weight should be chosen allowing the person to complete 3 sets at reps of 12, 10, and 8 respectively. The last 2 reps in each should be difficult but not forced. Every contraction should be coordinated with expiration in order to minimise the possibly increased risk of pneumothorax. Between 5 and 10 exercises should be performed. Three different series of exercises should be available to the patient incorporating different muscle groups in order to give the patient adequate recovery and rest. The program could also vary exercises, rep and set ranges in order to incorporate hypertrophy, strength and power exercises.
Duration
Ideally an effective intervention would have a duration of 30 minutes per day with adequate time for warm up and cool down. However patients exhibiting diminished fitness levels or work capacity due to moderate to severe lung dysfunction may only tolerate 5 minutes of exercise at the beginning of the program. This should then progress to 10/15 minutes in a two week period. In some sessions the total load can be spread over two sessions. For resistance training all sessions should be completed in roughly 40/50 minutes. After this period strength gains begin to plateau and eventually diminish. The program should have a minimum duration of 8-12 weeks to ensure that substantial training gains can be achieved.
Frequency
The exercises should be completed a minimum of 3 days a week. Ideally the exercises should be completed 6 days a week in patients with little or mild dysfunction. By alternating muscle groups and modalities of aerobic exercise this can be achieved. Patients exhibiting severe dysfunction have to have rest days incorporated into their program.
(Skinner, 2005)
Compliance issues
Any beneficial effects of regular exercise are rapidly lost if activity is ceased and therefore compliance to exercise regimens is a very important issue. (Zach et al, 1982) Non compliance to prescribed physical training may contribute to deteriation signs and symptoms of respiratory disease and a reduced ability to perform activities of daily living and thus ultimately have a detrimental affect on the individual's prognosis. (Bradley et al, 2002)
There are several physiological factors that influence adherence to exercise for CF sufferers. Factors such as decreased pulmonary function, poor nutrition, lack of peripheral muscle strength and reduced respiratory muscle efficiency can be experienced by CF patients and attribute to poor compliance.
The extent to which patients comply with recommended treatments appears to depend on the complexity and the longevity of both the disease and its treatment. Several factors, including gender, age, and disease progression, may influence the degree to which an individual complies to any treatment regimen, including exercise. (Bryon et al, 1996) Gender has not been associated conclusively to exercise compliance with only limited research in the area. Compliance to medical treatment regimes is often poor across all ages; however as children with CF get older there is an increased need to have more control over their treatment. As such there is sometimes a tendency to rebel against authority often resulting in problems with compliance in this particular age group (Gudas et al, 1991)
Complicated treatment regimens have been linked with decreased rates of compliance. The lack of immediate benefits from particular aspects of treatment regimens in CF makes it particularly difficult to maintain troublesome routines. It is likely that those who report immediate improvements in symptoms will be most comply with that therapy. (Koocher et a,l 1987)
Several psychological factors will influence whether the sufferer will comply with their exercise regime. These include factors external to the patient including social support, their perception of competency, self-esteem, enjoyment of the activity and factors associated with the patient's behaviour for example motivation and choice. (Cerny et al, 2002) Support from family, instructors, coaches, teachers, healthcare professionals and peers is influential in determining activity-related self-esteem and therefore activity behaviour. For children with CF, parents are of extreme importance. (Cerny et al, 2002) (See Appendix)
A study by Myers. (2009,) (n=563) explored the relationship between psychological and demographic variables relating to chest physiotherapy and exercise in adults with cystic fibrosis. They found adherence to CP and exercise was low (CP=29.5%; exercise=24.2 %), and that self-report measures of adherence tend to be overestimated. Therefore they concluded adherence was probably even lower. Females also reported lower exercise adherence, believing it to be less important and more of a burden than males. However the gender findings were only preliminary and should be only taken as such. (See Appendix)
Similarly to the above study research carried out by Dalcin et al. (2007), (n=38), found that self reported adherence of patients attending a program for adults with CF to be good. Furthermore the self-reported patient adherence score correlated inversely with the clinical score. (r = −0.36, p = 0.028).
However a recent study by White et al found adherence levels to be acceptable and higher than previously reported. Furthermore they found that lack of time was the primary reason for non adherence. (See Appendix)
There are several limitations with the above literature on measuring compliance and adherence. As such there is a pressing need for more accurate measurement tools so that programs can be adapted specifically. Furthermore there is a need for more longitudinal studies.
Conclusion
Research has shown exercise is an essential component of effective physiotherapy and imperative in slowing the decline in lung function for patients with CF. It also is vital for CF patients as they try to live as normal a life as possible and complete activities of daily living. An effective training program should be simple, based on prior testing and be progressive in nature.
There is justification to include aerobic, anaerobic and strength training exercises and all but strength training can be implemented in younger populations. Frequency, intensity and duration will depend on the prior testing and severity of the disease.
There are several issues with compliance among CF patients that are both physiological and psychosocial in nature. Support from parents, peers and health care professional is essential as the CF patient tries to comply with an exercise program. Future studies may find it useful to use psychological frameworks such as the transtheoretical model, the self-determination theory and the theory of planned behaviour to develop strategic plans to engage patients in physical activity.
References
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