Congenital Adrenal Hyperplesia (CAH) is a group of automosal recessive disorders that develop due to a deficiency of one of the five enyzmes necessary for cortisol synthesis in the adrenal cortex. Research indicates a predisposition in children and adolescents with CAH towards adverse metabolic changes such as obesity, hypertension, insulin resistance and increased intima-media thickness. This study aims to compare the extent to which children and adolescents with CAH are effected in terms of respiratory and peripheral muscle strength, exercise capasity, physical fitness and physical activity levels compared o their matched healthy individuals.

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive diseases caused by the deficiency of one of the five enzymes necessary for cortisol synthesis in the adrenal cortex. Dysfunction in cortisol synthesis, as seen in other enzyme deficiencies, leads to an increase in adrenocorticotropic hormone (ACTH) secretion, resulting in hypertension and hypokalemia. Additionally, patients with CAH exhibit excess androgens alongside cortisol deficiency. İn CAH treatment, glucocorticoids are used to suppress androgen production in the adrenal cortex. Deficiency in glucocorticoids and mineralocorticoids, as well as excess androgens, can contribute to the development of adverse metabolic and cardiovascular anomalies.

Ongoing research has revealed a predisposition for adverse metabolic changes in children and adolescents with CAH, including obesity, hypertension, insulin resistance, and increased intima-media thickness, which can increase the risk of developing cardiovascular disease in adulthood. Furthermore, subclinical left ventricular diastolic dysfunction has been observed in adolescents with CAH. İn these patients, due to the deficiency of epinephrine there is an increased tendency for hypoglycemia under stress conditions.

These metabolic changes can lead to impaired exercise performance in patients with CAH, consequently affecting their quality of life.

A study involving twenty classic CAH adolescents and twenty healthy counterparts demonstrated that classic CAH patients exhibited reduced exercise capacity with lower peak workload and higher peak systolic blood pressure during exercise. However, there is a lack of research in the literature comparing respiratory and peripheral muscle strength, daily life activities, physical fitness, and levels of physical activity in children and adolescents with CAH to their healthy peers.

Inclusion Criteria for CAH Group:

• Diagnosed with Congenital Adrenal Hyperplasia
• Aged between 8-18 years
• Providing voluntary consent from both themselves and their parents
• Able to cooperate

Exclusion Criteria for CAH Groups:

- Having any systemic disease that may affect the measurement parameters

Inclusion Criteria for Healthy Group:

• Not having any chronic diseases
• Aged between 8-18 years
• Willing to participate in the study
• Able to cooperate

Exclusion Criteria for Healthy Group:

• Not willing to participate in the study
• Presence of cooperation and communication problems

Children and adolescents aged 8-18 years diagnosed with classical congenital adrenal hyperplasia (CAH) who apply to and are followed up by the Hacettepe University Hospital, Pediatric Endocrinology Department will be accepted for the study. The snowball sampling method will be used for our control group. The investigators plan to contact the patient's relatives and then contact someone else in the same way.