Hematological malignancies arise from deficiencies in blood cell lineage which represent a heterogeneous group including leukemias, lymphomas, myelomas, myeloproliferative diseases and myelodysplastic syndromes. In recent years, a great majority of patients with hematological malignancies often experience side effects of disease related treatments such as chemotherapy with multiple agents, radiotherapy, corticosteroids, combination of medical drugs, autologous and/or allogeneic hematopoietic stem cell transplantation (HSCT) throughout their remaining lives. Furthermore, there are substantial outcomes regarding the initial time of diagnosis that pulmonary function involvements, sedentary life style (39%), decreased exercise capacity and lower extremity muscle weakness have been present in patients with lymphoma even before first cycle of chemotherapy is administered to patients. During the period of or after chemotherapy, patients have suffered from decreased maximal oxygen uptake, advanced muscle weakness, decreased hemoglobin levels and evident fatigue, as well.

As the treatment process continues for patients with hematological malignancies, HSCT is begun to schedule for almost all patients which has a significant potential for good clinical outcomes along with longer life expectancy. However, especially allogeneic-HSCT is a quite aggressive treatment option due to serious complications such as graft versus host disease, long term severe treatments of these complications and severe immune suppression related infections. Moreover, patients have already been exposed to immobility condition, low level of physical activity, pulmonary functions involvements, respiratory and peripheral muscle weakness as well as exercise intolerance before HSCT. In addition, the outcomes obtained from candidates just before HSCT have indicated that quadriceps femoris muscle strength, exercise capacity evaluated with 6-minute walk test, inspiratory and expiratory muscle strength are decreased respectively in 23%, 58%, 42% and 89% of candidates. Sarcopenia (50.6%), reduction in hip flexor, hip abductors and ankle flexors muscles strength and decreased diffusing capacity of the lung for carbon monoxide (78%) have also been mostly observed in HSCT candidates. In a study, candidates who were evaluated using a metabolic holter device are inactive (average 2180 steps/day) before HSCT. In another study, number of steps evaluated using a pedometer which provides only one output about step count are approximately 201.1 steps per a day for HSCT candidates. Accuracy of pedometers can be reduced at slow walking speeds so that pedometers may not be suitable for cancer patients. On the other hand, metabolic holter devices use pattern recognition technology to evaluate physical activity level that may produce more accurate estimation of energy expenditure in cancer population. Besides, it has also been stated that quadriceps femoris muscle weakness is related to reduced daily number of steps, therefore if the muscles are strengthened, number of steps may be increased at the process of HSCT.

Physical activity is any bodily movement which is produced by skeletal muscles concluded energy expenditure. While total daily energy expenditure demonstrates all types of energy costs including resting, diet-induced and activity-induced energy expenditures within 24 hours, active energy expenditure related with physical activity is produced by daily living activities such as employment, sport and any other activities. Activity energy expenditure also decreases with excess body weight, older age, female gender, loss of muscle mass and diseases throughout life span . On the other hand, Canadian Academy of Sports and Exercise Medicine recommends that people prefer moderate-to-vigorous physical activity (\>3.0 metabolic equivalents (METs)) including brisk walking, aerobic and resistance exercises, jogging, hiking, swimming and field games with ball or racquet for 150 min/week and a total sustainable activity duration from 30 min to 60 min per practice rather than sedentary behavior (\<1.5 METs) in order to decrease risk of most major chronic disease by 25-50%. Moreover, a 15 min/d or 75 min/week of moderate-to-vigorous physical activity is also recommended as about 15% mortality risk reduces in diseases and benefits increase . Given the importance of physical activity assessment and counseling in people with/without chronic disease, according to literature, studies objectively investigating either detailed physical activity condition rather than number of steps or relations of physical activity with pulmonary and physical functions in allogeneic-HSCT candidates are scarce. Therefore, primary aim of the current study was to exhibit possible all detailed aspects of physical activity outcomes evaluated with a metabolic holter, an objective measurement device, secondary aim was to investigate relationship among physical activity parameters, pulmonary functions and physical functions in allogeneic-HSCT candidates and as finally, to identify independent predictors of physical inactivity in candidates was aimed.