Chronic venous insufficiency (CVI) is defined as a very common condition that affects the venous system in the lower extremities, including various pathologies and subjective symptoms such as pain, cramps, restlessness in the legs, edema, itching and skin changes. CVI is a disease that develops due to venous hypertension in the lower extremities, resulting in impaired turbulent flow fields, venous distention, free radical formation and inflammation. In addition to being a cosmetic problem, symptoms such as pain, itching, burning, tingling, night cramps, edema, skin changes and venous ulcers in chronic cases can be seen. It is seen between 5-30% in the adult population. CVI affects 40% of the general population. Because of its high prevalence, chronic venous diseases are a common condition that causes major socioeconomic impacts. According to the studies; it has been observed that 32% of women and 40% of men have varicose veins, and any type of venous disease affects 40-50% of men and 50-55% of.

The main clinical features of CVI are dilated veins, edema, leg pain, muscle cramps, and cutaneous changes in the leg. Edema begins in the perimalleolar region and ascendes up the leg. Leg restlessness is often described as heaviness or pain after prolonged standing and is relieved by leg elevation. This discomfort is caused by increased intracompartmental and subcutaneous volume and pressure. Venous valves and venous pump are the two major determinants of venous flow. Venous valves play a role in directing the flow from the superficial system to the deep system and in its progression from the proximal veins to the distal veins.

Venous function is reflected in venous return, venous resistance, and its effects on cardiac output. Venous filling time is a parameter of venous function and is shortened as a result of valve insufficiency, vessel wall enlargement and inability of muscle pumps to work actively. The calf muscles compress the deep intramuscular veins, diverting blood flow from the veins to the heart. This mechanism depends on talocrural mobility and the force of contraction of the calf muscles. However, muscle pump dysfunction is not limited to the calf, but also includes inspiratory muscle dysfunction, such as when the diaphragm allows greater blood flow to the heart from the lower extremities, creating a suction effect on the inferior vena cava during inspiration and expiration. It has been shown that the respiratory cycle affects the increase of deep inspiration and the flow rate of the femoral vein and venous return in healthy individuals. When inspiratory muscle strength is insufficient, blood flow in the leg veins will decrease, increasing vascular resistance and thus systemic refill can be reduced. Increasing the muscle strength of inspiration with inspiratory muscle training is considered to increase venous return and improve symptoms of CVI, including pain and edema. However, there is insufficient evidence of inspiratory muscle training on venous function, clinical severity, symptoms and functional capacity and quality of life in CVI patients. Therefore, in the study, the investigators aimed to determine the effectiveness of inspiratory muscle training in individuals with chronic venous insufficiency.