Background: Numerous medical disciplines have recognized the preoperative period as a crucial phase to enhance patient recovery and outcomes. Patients perform preoperative pulmonary rehabilitation with inspiratory or expiratory muscle training to enhance lung protection. Despite the variety of breathing techniques in the clinical setting, the literature lacks a conclusive evidence regarding which technique is more effective. Research question: In adult patients undergoing open heart surgeries, is preoperative pulmonary rehabilitation of benefit in preventing postoperative pulmonary complications, shorten length of stay in the intensive care unit (ICU) or hospital? Methods: The authors conducted a search in electronic databases regarding the current evidence of preoperative pulmonary rehabilitation. Subjects: Patients undergoing Coronary Artery Bypass Grafts (CABG) and/or valvular surgery. Intervention: Any pulmonary intervention, such as incentive spirometer, inspiratory muscle training, exercise training or relaxation, delivered prior to surgery, single or combined. Outcome measures: The incidence of persistent post-concussion symptoms (PPCSs), pulmonary function test (PFT), ventilation period, length of stay in ICU and hospital Results: The authors conducted an initial search in the systematic reviews, which yielded 16 published articles. Furthermore, the authors search in the randomized controlled trials and this yielded 72 articles.  The relevancy of the selected publications was determined by reviewing their titles, keyword, and abstracts. Overall a total of eight  randomized controlled trials (RCTs) and six systematic reviews involving 3908 participants were included in this review. Conclusion: Preoperative pulmonary rehabilitation utilizing various breathing techniques reduces the incidence of postoperative pulmonary complications. Keywords Preoperative Care, Breathing Exercises, Postoperative Complications, Coronary Artery Bypass, Cardiac Surgery.