Does anyone know how low is too low for blood pressure?

Low blood pressure, hypotension is not always bad in it self. Accompanied by dizziness or fainting or difficulty breathing can be a problem. Dehydration can cause low bp, as well as many other things. The low end is gauged around 90/60. The pulse low end is 60. Take bp in both arms if you get abnormal reading, and make sure batteries don't need to be replaced.

90/60 is the lower limit, but look at the pulse pressure too. That is the difference between the two numbers and it should be 30 to 60. So if the patient only has 20 between the upper and lower number, the heart is not pumping well.