['Intradialytic hypotension remains the most common complication of routine outpatient hemodialysis treatments. There is debate as to the optimum dialysate sodium concentration, with hypotonic dialysates potentially causing intracellular swelling and hypertonic ones intracellular dehydration.', 'Multi-frequency bioimpedance was used to assess extracellular and intracellular fluid volumes in 53 adult hemodialysis patients. Dialysate sodium was checked by ion electrophoresis.', 'The mean decrease in extracellular volume and intracellular volumes were 1.01 ±0.09 and 0.88 ±0.18 kg, respectively. The median dialysate to sodium gradient was -3 mmol/L (-1 to -6), with a median dialysate sodium of 136 mmol/L (136-138). There was no association between changes in body fluid composition and sodium concentrations, or gradients. The mean difference between dialysate sodium prescribed and delivered was 2.4 ±0.8 mmol/L.'] Does negative dialysate to sodium gradient lead to intracellular volume expansion post hemodialysis?