Should runners drink alkaline water?
There are two performance benefits I have heard: digestive health and recovery.
For digestive health, the idea is that the higher (more basic) PH of alkaline water can help neutralize the acid naturally present in the stomach. I have not seen any clinical research supporting this claim. And, intuitively, the volume of stomach acid seems too much to be neutralized meaningfully from bottled alkaline water.
For recovery, the idea is that running produces lactic acid and excess hydrogen ions in the muscles. This is true. The argument is that alkaline water can help neutralize the acid and hydrogen ions. Again, I have not read any clinical research supporting this claim --- it seems that the amount of water available in the body would dilute any alkaline benefit from the bottled water before it reached the muscles.
So, are there any benefits for drinking alkaline water? In my experience, I see two potential benefits.
First is taste. Leading alkaline water brands smartwater and Essentia manufacture alkaline water through purification and then an ionization process. Purification removes trace elements and minerals present in tap water --- including a natural acidity. The result is water with a less bitter taste, in my experience.
Second is minerals. Some alkaline water is naturally alkaline. This water is derived from natural springs or artesian wells. The presence of natural earth minerals such as calcium and magnesium creates a "heavier", naturally alkaline water. Often called mineral water, this type of alkaline water has helpful minerals.
Should you drink alkaline water? In the end, I say give it a try. If you don't like the taste, you can always go back. But, stick to sports and electrolyte drinks for improved performance.