Objective
The aims of this study were to know the effects of long time bed immobilization on the heart rate variability and to know the correlation between the heart rate variability and other anthropometric parameters.

Method
The subjects of this study were 60 normal sedentary persons as control group and 22 patients who had been immobilized for a long time because of musculoskeletal problems without any systemic diseases. The heart rate variabilities were measured through the R-R interval variation at rest, deep breathing and valsalva maneuver. These values were compared between control and patient group and were analysed for correlation with age, weight, height, body mass index (BMI), amounts of smoking (pack years), spans of immobilization and physical activity scale (PAS).

Results
The mean heart rate variability of patients were 0.132⁑0.072, 0.216⁑0.109, and 0.289⁑0.171 in rest, deep breathing and valsalva maneuver respectively which were lower than the corresponding 0.176⁑0.085, 0.314⁑0.146, and 0.322⁑0.174 of normal control group. The heart rate variabilities were negatively correlated with age, BMI and amounts of smoking but positively correlated with the height. The physical activity scale of preimmobilization state was negatively correlated with resting heart rate variability but was positively correlated with heart rate variability during deep breathing and valsalva maneuvering state.

Conclusion
The long bed immobilization significantly decreased the heart rate variability and the heart rate variability could be used as a useful tool to measure the effects of immobilization on the heart.