Tom- I've really been paying attention to how much I drink on my runs the last year or so, in the summer (temps 60-80) I can get by a little over an hour on a single 20 oz bottle, now (temps from 10-30F) that same bottle last over two hours- definitely makes a difference

Mike

Many of the studies that Noakes uses to illustrate his point are from soldiers put on forced marches in desert heat over multiple days. In some instances purposely put on low salt diets beforehand to see if that would cause issues.

Noakes not only uses studies that he designed but also studies from researchers on the "other side." He explains why the data doesn't show what they claim it did. He worked with this data for decades. He seem fearless to look at anything that might prove he is wrong. He was so saddened by the deaths he saw after distance races due to overhydration he felt compelled to act. IIRC he said that in reviewing the records for marathons over the decades he found no record of anyone dying until the hydration recommendations started. One of the most interesting things he found was that discovering the most dehydrated person was easy because it was always the winner of the race. His point was that it obviously didn't affect their performance.

All the comments I have seen in this thread are addressed in the book. Some that have been mentioned such as salty sweating, muscle cramping, need for salt pills or electrolytes.

I know distance backpackers are incredible athletes but I have had the privilege of having a friend, the late Rick Sayre, who was an world class marathon runner. He is the only person to qualify for the US Olympic Marathon trials five times. in my opinion it is highly unlikely that there is any distance backpacker whose fitness could come close to world class marathoners. The demands they put on their system day after day year round makes us look like pretenders.

The two part summary is somewhat useful but it would be like trying to outline "War and Piece" in four pages and saying you read the book. It has been six months since I read "Waterlogged" but I am considering reading it again because there is so much interest.

"Tom- I've really been paying attention to how much I drink on my runs the last year or so, in the summer (temps 60-80) I can get by a little over an hour on a single 20 oz bottle, now (temps from 10-30F) that same bottle last over two hours- definitely makes a difference"

That pretty much mirrors my experience when I was still running, Mike. There is a big difference between hydration and over hydration, and 20 oz is definitely in the zone, IMO. Do you use electrolytes in hot weather, or are you one of those fortunate souls who can do without?

"My experience is that the athlete will need to replenish body salts or whatever you want to call them. Same for hiking or working hard in the desert."

+1 To which I would add that you don't have to be in a life threatening situation to make it worthwhile. Just a good old fashioned bout of leg cramps will teach you that it is well worth while to keep your electrolyte levels up to snuff. They can really ruin your whole day.

I use them- usually an Endurolyte and a Saltstick- every hour or two; I read up on stomach distress at ultras and lot of fingers pointed at lack of Na. I experienced it headed up the South Rim on our R2R2R and my hope is not to experience it again :)

If you suspect a sodium deficiency, which works better: sodium chloride or sodium bicarbonate?

I find the latter to be more helpful.

--B.G.--

no clue? I have taken a glass of water/bicarbonate for acid relief and it does seem to work