Blood pressure
From Tardis Wiki, the free Doctor Who reference
According to the Twelfth Doctor, a binary vascular system led to extremely high blood pressure in comparison to single-hearted species like humans. (TV: Smile) The Thirteenth Doctor was noted to have high blood pressure, as well. (TV: Kerblam!)
For humans, a blood pressure of 60/90 was "not good". (AUDIO: Visiting Hours)