If it is blood pressure, you're probably somewhat dehydrated. The biggest cause of high blood pressure (in my opinion) is dehydration. I have been told drinking a quart of water for every 50 pounds of body weight, plus one quart a day is the minimal one should drink (and if you're sick you should drink one more).
Actually sodium does not cause dehydration, lack of water and poor water metabolism and fluid utilization cause dehydration. If you cut your sodium back too much you can cause problems just as much as if you don't drink enough water. I cut my sodium intake way back 24 years ago and when I finally tested (kinesiology) for how much I should be taking in, for about two months I needed to take in two teaspoons of salt a day. Now I am not nearly so stingy with the salt and my body is much happier for it. But I do drink a lot of water too.