Introduction. One of the main factors affecting postoperative outcomes in patients with advanced ovarian cancer is the cardiopulmonary status. Several studies have reported that preoperative multifactorial rehabilitation and physical fitness can lead to reduced postoperative morbidity, mortality, shorter length of stay, and improved quality of life in cancer patients. The issue of adaptability to physical activity of overweight and obese patients who undergoing debulking surgery is insufficiently studied. The study of compensatory changes that occur in physically inactive obese patients remains relevant, especially against the background of neoadjuvant chemotherapy, in the conditions of preoperative preparation with ERAS-recommended physical activity.
 The aim of the study is to determine the differences between women with advanced ovarian cancer and obesity compared to women with normal weight in terms of heart rate variability during exercise. To assess the adaptive capabilities to physical activity of patients with advanced ovarian cancer and obesity at the stage of preoperative preparation, who undergoing debulking surgery.
 Result. Achieved METs, peak HR, CI, and HR recovery were higher in nonobese women, whereas training had no significant effect in obese women. Women who had already received neoadjuvant CT achieved a lower level of MET (6.8 ± 3.2 vs. 8.9 ± 4.1; P < 0.001). Also, peak HR and CI were lower in women after neoadjuvant CT (126±27 vs. 138±20; P = 0.001 and 0.65±0.22 vs. 0.71±0.22; P = 0.001, respectively). BMI was a significant predictor of exercise capacity only in the obese subgroup, whereas age, peak HR, and prior adjuvant HT were always significantly associated with METs achieved.
 Conclusions. No significant difference was found between trained and untrained women with comorbid obesity in HR behavior or physical capacity. Different heart rate behavior in patients of this group is thus explained by obesity as such, regardless of the degree of physical training.