Bicarbonate is the least glamorous number on a routine blood panel. It sits on the metabolic panel next to sodium and potassium; it reflects how the body is buffering acid, and almost nobody looks at it unless something is wrong.
Two researchers examined it over 21 years of national survey data and found that it had been climbing the entire time. Average serum bicarbonate in the U.S. National Health and Nutrition Examination Survey increased from 23.8 milliequivalents per liter in 1999 to 25.3 in the 2019 to 2020 cycle, an increase of roughly 7%, or about 0.34% per year.
