Does Drinking Water Lower Blood Pressure? Trials Don’t Show It; a Big Glass Raises It

In the largest published trial we found, 316 of 631 adults with kidney disease were coached to drink more water for a year and drank about 20 oz more a day; among the 590 measured at the end, their top number fell half a point more than the comparison group's (both fell about 5 points), a gap that chance could explain. Smaller trials pointed both ways. What water measurably does is the opposite: a 16-oz glass raised the top number of 11 healthy volunteers, average age 57, by 11 points within the hour.








