# Exercise as it relates to Disease/Aerobic vs Anaerobic exercise for children suffering from Cystic Fibrosis

Cystic Fibrosis (CF) is the most common life threatening genetic condition in Australia. It primarily affects the respiratory system (lungs), the digestive system (pancreas and sometimes liver) and the reproductive system. When a person has CF, there is a problem with the protein that controls the movement of salt in and out of the cells. Their mucus glands secrete very thick sticky mucus. In the lungs, the mucus clogs the tiny air passages and traps bacteria. The pancreas is also affected, preventing the release of enzymes needed to digest food. This means that people with CF can have problems with nutrition and must consume a diet high in kilojoules, fats, sugar and salts. The thick mucous also stops digestive enzymes in the pancreas from reaching the small intestine, which leads to difficulty with digesting fats and absorbing some nutrients. Some people with CF also experience liver disease.

## Background
### Signs & Symptoms:

* A persistent cough, with great physical effort
* Some difficulty breathing
* Tiredness, lethargy or an impaired exercise ability
* Frequent visits to the toilet
* Salt loss in hot weather, which may produce muscle cramps or weakness
* Poor appetite
* Frequent chest infections

### How Cystic Fibrosis affects Children:

Cystic fibrosis is the most common cause of pancreatic insufficiency in children. Because CF produces thick mucus within the respiratory tract, kids with CF may suffer from:
* Nasal congestion
* Sinus problems
* Wheezing
* Asthma-like symptoms
Children with CF begin having symptoms at birth. Some are born with a condition called meconium ileus. Although all newborns have meconium — in CF, the meconium can be too thick and sticky to pass and can completely block the intestines. More commonly, babies born with CF don't gain weight as expected. They fail to thrive in spite of a normal diet and a good appetite. This is due to the mucus blocking the passageways of the pancreas and prevents pancreatic digestive juices from entering the intestines. Without these digestive juices, the intestines can't absorb fats and proteins completely, so nutrients pass out of the body unused rather than helping the body grow. As CF symptoms progress, they can develop a chronic cough that produces globs of thick, heavy, discolored mucus.

## Exercise as Treatment

When kids are first diagnosed with CF, they'll have diagnostic tests, especially baseline measurements of their breathing (lung function) and a nutritional assessment. Their basic daily care programs will vary from child to child, but they usually all include pulmonary therapy (treatments to maintain lung function) and nutritional therapy (a high-calorie, high-fat diet with vitamin supplements). Exercise benefits us all, but children with CF benefit even more from being physically active because exercise can:
* Slow the rate of decline in lung function, which means children with CF may keep good lung function longer.
* Help clear mucus from the lungs, allowing for easier breathing.
* Create more reserve for the whole body to rely on, during periods of lung infection. This means that someone who is fit may be able to resume their activity faster following a bout of illness.

### Can I Exercise with Cystic Fibrosis

Exercise is encouraged on a regular basis. Physical activity and exercise training play an important role in the clinical management of children with CF. Exercise training is more common and recognized as an essential part of rehabilitation programs and overall CF care. Regular exercise training is associated with improved aerobic and anaerobic capacity, higher pulmonary function, and enhanced airway mucus clearance. However, exercise training remains underutilized and not always incorporated into routine CF management.

### Cystic Fibrosis and Aerobic Exercise

Aerobic exercises include any kind of activities using large muscle groups that can be maintained continuously in a rhythmic manner (e.g., swimming, cycling, or running). It has also been reported that peak and early oxygen consumption (VO2) recovery are significantly related in children with chronic lung disease, implying that the greater the aerobic fitness, the faster the rate of recovery following exercise. Recent research has demonstrated that the time spent on physical activity in children with CF is similar to that of healthy children, but healthy children spend more time exercising at vigorous intensities. Furthermore, it has been recognized that children with CF have higher activity levels, greater aerobic fitness, enhanced nutritional status, and significantly lower progression of disease. Children with higher aerobic fitness have an improved survival.

### Cystic Fibrosis and Anaerobic Exercise

Anaerobic activities are characterized by high intensities of short durations (lasting typically up to 30 seconds), being predominantly fuelled by non-oxidative sources of ATP resynthesis. Previous studies investigating anaerobic performance of children with CF showed lower values compared to healthy subjects. Furthermore, children with CF with higher levels of habitual activity have been found to possess increased anaerobic power during the Wingate Anaerobic Test. These higher levels of activity are likely influenced by several factors such as the extent of malnutrition, muscle mass, mitochondrial.

## Recommendations
### Exercise Considerations

Specific risks of exercise training in CF are presented in the table. During prolonged exercise, as a consequence of excessive sweat and sodium losses, children with CF are advised to drink repeatedly (i.e., every 15–20 min). Especially, in hot conditions, children may underestimate their fluid needs with the risk to undergo excessive dehydration.
| | Children with mild to moderate CF | Children with sever CF |
| Recommended Activities | Walking, running, bike riding, swimming, roller-skating and trampolining | Walking, strengthening exercises, gymnastics and day-to-day activities |
| Method | Intermittent and steady-state | Intermittent |
| Frequency | 3 -5 times per week | 5 times per week |
| Duration | 30 – 45 minutes | 20 30 minutes |
| Intensity | 70% - 85% Heart Rate max; 60% - 80% Peak VO2 | 60% - 80% Heart Rate max; 50% - 70% Peak VO2 |
| Oxygen Supplementation | Indicated, if oxygen saturation drops below 90% during exercise | Indicated, if oxygen saturation drops below 90% during exercise |
| Activities to Avoid | High altitude activities | High altitude activities |
| Potential risks associated with exercise and training | Dehydration, hypoxemia, bronchoconstriction, pneumothorax, hypoglycaemia, rupture or liver and spleen. |

## Further reading

* Cystic Fibrosis Australia
* Cystic Fibrosis American Foundation
* Kids Health

## References

* 1 2 cystic fibrosis.org
* 1 2 BetterHealth CF
* ↑ Cystic Fibrosis 4 Kids
* ↑ . Craig A Williams & Daniel Stevens., 2013, Physical Activity and Exercise Training in young people with Cystic Fibrosis. VOL 2, NO. 2
* ↑ , Craig A Williams, C Benden, D Stevens & T Radtke., 2010, Exercise Training in Children and Adolescents with Cystic Fibrosis: Theory into Practice.
* ↑ , D. Stevens, P. J. Oades, N. Armstrong, and C. A. Williams, “Early oxygen uptake recovery following exercise testing in children with chronic chest diseases,” Pediatric Pulmonology, vol. 44, no. 5, pp. 480–488, 2009.
* ↑ , P. A. Nixon, D. M. Orenstein, and S. F. Kelsey, “Habitual physical activity in children and adolescents with cystic fibrosis,” Medicine and Science in Sports and Exercise, vol. 33, no. 1, pp. 30–35, 2001.
* ↑ , H. C. Selvadurai, C. J. Blimkie, P. J. Cooper, C. M. Mellis, and P. P. Van Asperen, “Gender differences in habitual activity in children with cystic fibrosis,” Archives of Disease in Childhood, vol. 89, no. 10, pp. 928–933, 2004.
* ↑ , S. R. Boas, M. J. Danduran, and S. A. McColley, “Energy metabolism during anaerobic exercise in children with cystic fibrosis and asthma,” Medicine and Science in Sports and Exercise, vol. 31, no. 9, pp. 1242–1249, 1999.
* ↑ , L. C. Lands, G. J. F. Heigenhauser, and N. L. Jones, “Analysis of factors limiting maximal exercise performance in cystic fibrosis,” Clinical Science, vol. 83, no. 4, pp. 391–397, 1992.
* ↑ , General exercise and training recommendations
* ↑ O. Bar-Or and T. W. Rowland, Pediatric Exercise Medicine: From Physiological Principles to Health Care Application, Human Kinetics, Champaign, Ill, USA, 1st edition, 2004.
* ↑ , O. Bar-Or, C. J. R. Blimkie, J. A. Hay, J. D. MacDougall, D. S. Ward, and W. M. Wilson, “Voluntary dehydration and heat intolerance in cystic fibrosis,” Lancet, vol. 339, no. 8795, pp. 696–699, 1992.