This is certainly a possibility. Water is a byproduct of lipolysis. Personally I have noticed that I seem to need less water when out for long days in the mountains. Since I’ve been coaching more and more mountain athletes I frequently hear that they also record much less water consumption that would be expected for their activity. Elite alpinists like David Goettler routinely does multi-hour, strenuous workouts on alpine terrain in Chamonix drinking 1/2 liter of water and one gel.

Another benefit for the highly fat adapted mountain athlete.

Scott

I think we might just want to rely on anecdotal evidence here:-). You can do an experiment on yourself and see if you notice a reduction in water consumption when fat adapted. My guess is that you will.

Scott

I’ve read that it isn’t mild dehydration that slows athletes down, but thirst. So to a point, is it psychosomatic?

Interesting read: https://www.plewsandprof.com/single-post/2015/11/10/Summer-breeze-skateboards-the-perfect-combination (No idea why “skateboards” is in the URL…)

I rarely take water because I hate carrying it. As Steve said, that has probably reduced my need for it because I’m used to going without.

This year, I did some experimenting to find just how much water I lose at different intensities and temperatures. That led to doing some ~2h skimo races without a water bottle because dehydration at race pace for two hours would be less than 3%. There was no performance decrement. In fact, it saved me over a pound of equipment because I could leave the bottle at home.

For me, two hours seems to be the magic mark for food and water. At two hours or less, neither are necessary. In fact, I suspect they may be counter to performance. In races, they’re excess weight to carry. In training, the calories are excess weight to store and run counter to glycogen depletion.

Over two hours, both are necessary, and I need to start consuming both within the first hour of activity. Watch alarms are key to keep me on a feeding schedule.

An exception to my two-hour rule is multi-day races. In that context, even if one day’s event is less than two hours, I would still feed and hydrate. It’s irrelevant to that day’s performance but speeds recovery for the following days.