People with cystic fibrosis, as well as their relatives, have many doubts about physical activity and the disease. The biggest fears are that physical activity can aggravate the symptoms and cause more intense exacerbations. If, instead, exercise can attenuate these symptoms and decrease the intensity and frequency of exacerbations. If respiratory tract complications, caused by the basic pathophysiology of the disease, may in some way limit performance during exercise or sports. As we realized that these are very common doubts, we decided to clarify them through this text, addressing all aspects of the physical exercise and outlining a more up-to-date overview possible on the effects of it on the treatment of cystic fibrosis.
Cystic fibrosis is a genetic disease, with an autosomal recessive characteristic, that reaches predominantly the white population compared to other populations. Classical manifestations of the disease include chronic obstructive pulmonary disease (COPD), pancreatic failure, and excessive accumulation of electrolytes in sweat, as well as male infertility.
As we know, the disease is caused by a mutation in a gene called CFTR that encodes the protein of the same name. Are known more than 1,900 different mutations in the CFTR gene, and these are grouped into classes according to the effect they have on the translation or about the other steps in the processing of the protein to reach the cell membrane, where the protein without the mutation should function as a channel for the ion chloride.
evolutionary course of the disease leads to a marked deterioration of the lungs, pulmonary hypertension and consequent impairment of respiratory function. This framework progressive especially affects the maximal oxygen consumption (vo2 max), the indicator for the physiological reference to the capacity of cardiorespiratory, the forced expiratory volume in one second (FEV1), clinical indicator powerful life expectancy and survival rate, and forced vital capacity (FVC) which is the maximum volume of air, and exhaled with maximum effort from a maximal inspiration.
In addition to compromising respiratory function, with the progressive reduction of VO2max and FEV1, in some way cystic fibrosis affects muscle strength, as it produces a picture of malnutrition and loss of muscle mass caused by the obstruction of pancreatic channels by mucous tampons. The obstruction prevents the secretion of enzymes into the duodenum, implying poor digestion and poor absorption of proteins, fats and carbohydrates. The muscle tissue contains 70 to 73% water, and 27 to 30% protein approximately, so any metabolic change involving protein malabsorption will lead to a picture of protein malnutrition, and consequently low rates of muscle strength.
How can exercise help in the treatment of cystic fibrosis?
The first study on the role of physical exercise in the treatment of cystic fibrosis, conducted in the year 1971, already revealed that the limitation of physical performance in cystic fibrosis should be exclusively the mechanics of pulmonary ventilation), specifically the increase in the dead space. Therefore, it indicated that possible increases in pulmonary ventilation produce direct benefits in pulmonary function, and consequently in the improvement of disease symptoms.
From the 1980s to this date, numerous scientific studies on physical exercises and cystic fibrosis have been carried out, with very promising and interesting results. These studies have revealed that aerobic physical exercise on a regular basis (1) helps to eliminate the mucus in the lungs due to the increase of the vibrations and of the pulmonary ventilation-VE, (2) desobstrui and clean the airways, (3) reduces the injury inflammatory in the lung tissue, (4) assistance in the strengthening of the respiratory muscles, (5) help to regulate the sodium channel – Na+, thereby inhibiting the entry of the same in the respiratory tract, what stimulates the increase of water content in the lung mucus and leads to more debugging of the mucus and reducing its viscosity.
Studies on the physiological effects of regular aerobic exercise indicate that it significantly increases VO2max, FEV1, VE and CVF. The results can be observed with only 3 weekly sessions, from 8 to 12 weeks of training, and they cause a positive impact especially on the quality of life and survival rate, because the extent to which we increase these indicators to clinical, especially Vo2max and FEV1, increased the life expectancy of patients with cystic fibrosis.
The studies of literature review and meta-analysis suggest that the aerobic physical exercise on a regular basis (1) mobilize the mucus and increases the transport mucociliary out of the pulmonary epithelium; (2) help to produce satisfactory levels of cardiorespiratory conditioning and strength while maintaining a good fitness for the exercise and activities of daily living; (3) maintains a normal mobility, especially of the thoracic region, helping in the debugging and cleaning of the mucus of the lungs; (4) prevents osteoporosis associated with cystic fibrosis, and physical inactivity; (5) increases self-confidence.
In addition to the beneficial effects of regular aerobic exercise, already described above, it seems that muscle strength training can help and much the patients with cystic fibrosis. Strength training produces micro-lesions in the structure and cells of muscle tissue, which initiate an inflammatory process. This inflammatory process, once initiated, activates a series of flags that are organic that communicate with specific hormones, such as testosterone and growth hormone, which regulate and activate pathways of nuclear protein synthesis that begins a process of encoding and transcription of amino acids into protein molecules, which will retrieve the micro-lesions and to induce the muscles to increase in size. Protein synthesis produces muscle mass gain, which reverses the protein malnutrition picture and low weight.
On the other hand, considering some physiological mechanism that is not yet fully explained, it seems that muscle strength training helps improve lung function as well. Regular force training for large muscle groups, performed 2 to 3 times a week, increases the CVF, decreases the residual volume-VR (trapping air in the lungs after maximum expiration) and decreases the VR/CVF ratio.
The recommendations of the principal organs of the search for aerobic exercise include continuous training of moderate to high intensity (MCT), with the accumulation of at least 150 minutes weekly, distributed with a minimum frequency of 5 days per week, with a minimum duration of 30 min. The recommended intensity is between 40-55 and 85% of VO2R (Reserve VO2), with VO2R representing the difference between VO2max and VO2 rest (3,5 ml O2/kg/min). The recommendations also suggest the variation of aerobic exercise with the method step of short duration and high intensity (HIIT), with the accumulation of weekly of at least 75 min of activity vigorously intense (vo2 max ≥ 90%), distributed in a minimum frequency of 3 days per week, with a minimum duration of 20 min.
The HIIT method is a very viable alternative and practice of aerobic exercise,
as it takes little time per session and can be done anywhere. The method consists of interval training with high intensity and short duration intervals (VO2max ≥ 90%), interspersed with low intensity and longer intervals (VO2Máx ≥ 40-65%). The aim of the HIIT method is to stimulate the anaerobic route of energy production during the period of maximum effort (active range), and to stimulate the aerobic route of energy production during the recovery period (recovery interval). A classic example of HIIT are workout sessions with 30 s interval active, and up to 4 min of interval skimmer, but generally a relationship work an average of up to 1:3 (ratio between the time length of the break and active recovery) is likely to be very accepted and indicated in the scientific literature, in addition to well-tolerated by most individuals, even those with cystic fibrosis.
The HIIT method seems to be more efficient than the MCT method in controlling the inflammatory response in the pumonar tissue. Some studies have shown that the HIIT method significantly reduced the concentration of some proinflammatory cytokines, such as IL-6 and TNF-α, compared to the MCT method. As the decrease of the inflammatory process of the lung tissue is one of the main goals of the treatment of cystic fibrosis, the adoption of the scheme of training, HIIT can be a good alternative, because it reduces the inflammatory response due to the short duration of the training sessions.
For outside muscle training, the recommendations indicate a load between 6 and 12RM, moderate muscle contraction speed (1-2 s concentric phase, 1-2 s eccentric phase), 1 to 2 min recovery interval between series. The minimum frequency weekly recommended is 2 to 3 days for beginners, 3 to 4 days for intermediate, and 4 or 5 days for individuals with advanced, and a schema with multiple series, applied to large muscle groups through exercises multiarticulares, to optimize the process of protein synthesis and an increase (hypertrophy) of the muscle mass.
But is there a case where the exercise is contraindicated? Patients who have saturation problems are afraid of shortness of breath during exercise. It is interesting to note even in rehabilitation sessions performed in patients with indication for lung transplant that exercise is not only recommended, but practically mandatory. So, if even in such a serious situation as in the need for a transplant it is possible to do exercises, how can it be possible for physical exercise to be contraindicated in people with a condition close to normal?
Sobre physical exercise for transplant patients, or with an indication of transplantation, some studies with a group of patients who received heart transplant and another group who were on a waiting list for lung transplantation indicated that even in your mode more vigorous and strenuous, the HIIT, the exercise was well tolerated and produced significant increases in indicators of clinical survival as Vo2max, FEV1 and dyspnoea (shortness of breath) in comparison to the MCT, and can be performed normally.
There are precautions to be taken, such as the monitoring of oxygen saturation and heartbeats in specific situations and the replacement of electrolytes during the most intense sessions or held on warmer days, as we speak in the specific text about hyponatremia (link).
But the truth is that the literature tells us that exercise is contraindicated in only two situations, which here is a note and warning: in the case of infection the patient should stop the exercise program until you are absolutely asymptomatic for at least 1 day, or the infection has been cured. Discontinuation is also recommended in cases of exacerbation of asthma symptoms until they have completely ceased. Only after this, it is recommended the gradual resumption of the program of physical exercises.
Finally, we should remember that the major organizations of research on physical exercise and cystic fibrosis recommend the adoption of a physical exercise program that includes aerobic training and strength training, supervised and developed by a physical education professional trained to practice this function.
So what are you waiting for? Do not waste any more time, make a detailed evaluation with the medical team that accompanies you, look for a qualified physical educator and start practicing physical exercises. Incorporate these new habits into your treatment routine. You will quickly observe the changes and improvements in your quality of life and clinical indicators of the disease, in addition to your self-confidence and then you will no longer want to stop. On the contrary, you will want to face bigger challenges!