The aim of our study is to assess disease severity, respiratory muscle strength, respiratory functions, pectoralis minor muscle shortening, functionality, and quality of life (QoL) in patients with upper limb lymphedema (ULL), and to compare these findings with healthy controls.The disease severity was assessed using the Stillwell classification system; respiratory muscle strength was measured through maximum inspiratory and expiratory intraoral pressures (MIP, MEP, respectively); respiratory functions were evaluated with a spirometer; pectoralis minor muscle shortening was measured with a tape measure; functionality was assessed using the Disabilities of the Arm, Shoulder and Hand (DASH); and QoL was evaluated with the Lymphedema Quality of Life Questionnaire - Arm (LYMQOL-Arm).

The study had a cross-sectional observational study design. The participants were divided into two groups, patients with ULL in Group 1; the healthy individuals were included in Group 2. All assessments for both groups were performed by two different physiotherapists.

Inclusion Criteria:

• aged 25-65 years with secondary, unilateral upper limb lymphedema in Phase 2 of the protection stage,
• wearing compression garments,
• who have not received manual lymph drainage (MLD) therapy in the last 3 months
• along with healthy controls of a similar age who volunteered to participate.

Exclusion Criteria:

• being in Phase 1 of lymphedema treatment (the edema-reducing phase),
• being classified as NYHA Class III and/or IV according to the New York Heart Association classification system,
• having a chronic respiratory disease,
• presence of active infection (such as lymphangitis or cellulitis), or undergoing radiotherapy/chemotherapy due to breast cancer.

aged 25-65 years with secondary, unilateral upper limb lymphedema patients and healthy controls