Effects of spontaneous physical exercise on experimental cancer anorexia and cachexia

The aim of this study was to evaluate whether spontaneous physical exercise can modify cancer anorexia and cachexia in tumour-bearing rats. Two transplantable experimental tumours were evaluated. Tumour-bearing Wistar Furth rats fed ad libitum and with free access to a running wheel had a delayed onset of anorexia compared with their non-exercised tumour-bearing controls, retained normal behaviour and were able to run the same daily distance as non-tumour controls until the onset of cachexia. Exercise resulted in a decreased carcass wet weight and lipid stores but in an increased carcass dry weight in the tumour-bearing animals. Despite increased food intake, physical exercise resulted in a reduced final tumour weight without any change in water content. Skeletal and cardiac muscle tissue did not show any difference in water content but there was an increased RNA/protein quotient in the exercising tumour-bearing animals. Thus the deleterious alterations induced by the malignancy on tumour host metabolism are not inevitable but can be modified by spontaneous physical exercise.