Interdialytic weight gain determines how much fluid (ultrafiltration) has to be removed during each hemodialysis session. High ultrafiltration volumes stress the organism and lead to a higher risk of death. Thirst is the main driving factor of interdialytic weight gain, and thirst is mainly driven by salt intake, molecules that increase blood tonicity (such as sugar in diabetics) and fluid loss (such as in dehydration and blood loss). It has been speculated that fluid loss during hemodialysis could increase the sense of thirst immediately following dialysis, but this statement requires further evidence.