Combined Exercises Grup: In addition to the aerobic exercise, the training group will be given respiratory muscle training once a day, 5 days a week, as a home program. Intraoral pressure measurements will be repeated once a week to calculate the new threshold load. Respiratory muscle training: Respiratory muscle training in 50% of MIP and 30% of MEP, as ICE + IME (5 days a week, 15 minutes per day, 15 minutes of IMI). Evaluations will be repeated before and after treatment. The original value of this study is that the effects of Respiratory Muscle Training Combined with Aerobic Exercise in addition to CPAP treatment will be investigated in individuals with OSAS.

Aerobic Exercises Grup: For gradual aerobic exercise training, bicycle ergometer training in the hospital environment and brisk walking at home once a week (3 days a week, 20-40 minutes a day) will be given under supervision two days a week Obstructive Sleep Apnea Syndrome (OSAS) is a syndrome with a highly complex pathophysiology characterized by repetitive complete or partial upper airway occlusions during sleep. As a result of collapse in the pharyngeal airways during sleep, air flow to the lungs decreases partially (hypopnea) or completely (apnea), hypoxia and hypercapnia develop, and the congestion ends with the end of sleep. The repetition of these situations that develop during sleep stimulates the sympathetic nervous system and causes changes in blood pressure.Excessive daytime sleepiness and neurocognitive disorders can be observed as a result of sleep disruptions and hypoxia that develop with multiple stimuli .It has been reported that there is a continuous increase in the prevalence of OSAS. The incidence of OSAS in the general adult population varies between 9-38%, with a higher incidence in males. Due to obesity, its prevalence is increasing at an alarming rate, especially in middle and high-income countries . OSAS causes potentially serious health consequences such as impaired quality of life, emotional impairment, neurocognitive impairment, permanent brain damage, cardiovascular morbidity, and sudden death during sleep. OSAS has a very complex pathophysiology and the roles of influencing factors are also variable among individuals. In the physiopathology of upper airway obstruction, factors such as anatomical and mechanical factors, impaired contractile function of upper airway muscles, respiratory control instability come to the fore . One of the mechanisms that cause altered neuromechanical responses in OSAS is the deterioration of the contractile function of the upper airway muscles. In these patients, the upper respiratory tract muscles work under hypoxic conditions and as a result, a modification in the muscle fiber structure develops. In this modification, muscle fibers change from type I fibers that are resistant to fatigue to type II muscle fibers that increase strength but are not resistant to fatigue. As a result, the contractility of the muscle is preserved, but the fatigue increases. With this modification in the muscle fiber, inflammation may occur in the muscle working under increased load, with muscle damage that impairs the contractility of the muscle. Muscle dysfunction may develop as a result of these events .

During sleep, there is a decrease in lung volume and upper airway dilator muscle tone. Therefore, upper and lower airway muscle function is relatively reduced during sleep and may increase airway obstruction. It is thought that increasing upper airway dilator muscle activity and increasing lung volume are effective in maintaining airway patency. Coordinated contraction of the upper airway dilator muscles (eg genioglossus) and inspiratory pump muscles (eg diaphragm) is required for breathing to continue with an open airway. Inspiratory muscle weakness increases susceptibility to hypoventilation during sleep .

Treatment methods of OSAS include conservative (Continuous Positive Airway Pressure (CPAP) device and intraoral device applications) and surgical interventions. CPAP therapy, which is the most effective method available in OSAS, has been shown to improve sleepiness, hypertension and many cardiovascular indices seen in patients . CPAP is considered the first choice in the treatment of especially moderate or severe OSAS cases, but it is costly and patient compliance is an important condition that affects treatment success.

It is known that respiratory muscle training increases respiratory muscle strength in people with COPD and neuromuscular diseases . It has been reported that inspiratory muscle training in OSAS patients improves OSAS severity, daytime sleepiness and sleep quality, decreases the severity and frequency of snoring, improves respiratory muscle strength, and can reduce the cost of CPAP treatment by increasing its use in rehabilitation programs. However, it has been shown that training applied to the upper respiratory tract with the didgeridoo instrument in people with snoring and OSAS reduces daytime sleepiness, apnea-hypopnea index, and upper airway collapse. Strengthening both inspiratory and expiratory muscles seems reasonable given that weakness of the upper airway and inspiratory muscles in these patients affects sleep-related outcome measures. In addition, it is stated in the literature that there is a need for studies on the benefits and results of the use of respiratory muscle training as an adjunct to CPAP or oral devices .

It is known that most of the patients with OSAS also have low exercise capacity. OSAS severity is associated with worsening exercise tolerance. In the treatment of OSAS patients, exercise training in addition to CPAP therapy has received increasing attention in recent years . It has been shown that regular exercise training applied in patients with OSAS reduces AHI, body weight and body mass index, improves aerobic capacity and quality of life . In a recent meta-analysis, aerobic exercise training has been reported to effectively improve quality of life, daytime sleepiness, and sleep quality . No studies were found that evaluated the effects of inspiratory and expiratory respiratory muscle training in addition to aerobic exercise in patients with OSAS. The aim of this study is to evaluate the effects of inspiratory and expiratory respiratory muscle training in addition to aerobic exercise in patients with OSAS.