altitude sickness?

I agree with the water analysis. Some people drink a lot of water, others don't, but the tale-tell sign here is the amount that it appears that you are increasing your intake from a normal day. If you are already working outside on a normal day, you shouldn't need the same % increase as someone who works in a cubicle when it comes time for the trail.

I've had this happen to some of my hiking partners when I was teaching backpacking clinics. Usually it's a problem to get them to drink enough water but whenever someone drinks too much it's just as bad.

Just a guess, but juding from what you've told us, plan on no more than 25% of your normal daily intake since you are already used to working outside. If feel like you need to go above that try gatoraid or similar. Even if you water it down to 50% for taste it'll upset your electrolite balance much less in that solution.

Others have found a good balance by alternating their drinking going from 1 L of water and then next an energy drink, then back to water.

Nuun is a energy drink that comes in tablets much like Alka-Seltzer and makes a fizzy drink. It's often a way for someone to get their soda pop fix while on the trail but be forwarned, the Kona-Kola takes some getting used to. The lemon lime isn't too bad though in my book.

Andrew, don't discount the possibility that you are experiencing altitude sickness. It sounds to me that is the most likely explanation.

The vast majority of people do not have any significant problems with altitude until they reach over 9000 or 10000 feet or more. However, everyone has a different susceptibility and some people are extremely prone to AMS. You may be one of these people!

It is not unheard of for some people to suffer from altitude sickness as low as 6,500 feet. If it is the altitude that is affecting you, then I would expect that you would feel fine on the first day of your trip. But during the night, or the next morning, after sleeping at altitude you might start to feel terrible, with nausea, vomiting and sweating as common symptoms. On descending from altitude the next day, you should start to feel better and at home the next night I would expect that you would be feeling pretty ok again (although probably a bit weak and tired).

The fact that you live in the mountains at 3000 feet does not mean that you cannot get altitude sickness at 7000 feet. Everyone is different, and everyone has their own 'level' which they can ascend to in just a day or two without experiencing serious symptoms… for most people it is around 9000 or 10000 feet.

Obviously the way to figure out whether it is actually altitude sickness is to examine the other trips you have done. Have you ever had these symptoms on trips below 5000 feet? If so, you can probably rule out altitude. If not, I would rate it as a possible or even likely explanation. You should test it out by planning another two day trip at low altitude.

I don't think you are drinking an excessive amount of water. Two litres (2.1 quarts) a day is recommended for everyone who isn't doing a lot of physical activity. If you are walking and sweating all day then 3 or 4 quarts would be a good amount I would think. It also sounds like you are getting plenty of salt, and I don't think protein is an issue either (especially on a 2 day trip).

Anyway, I would test out the altitude theory first. It might be wise to go and see a doctor before your next trip even if it is at low altitude, to give you a bit of a checkup and make sure nothing serious is amiss.

Do let us know what the final diagnosis is!

I wonder if you use a hydration system like a platypus. Maybe it needs to be cleaned or bleached. Or maybe your water bottle is dirty. Or maybe your filter needs to be bleached.
Good luck, Josh

To me your symptoms sound an aweful lot like serious caffeine withdrawel. Do you drink a ton of coffee and other caffeinated beverages in your normal life then cut it out completely when on the trail?

I used to drink 4 or 5 large coffees a day during my workday life, and I got terrible headaches, nausea, and other symptoms when I cut it off suddenly in the mountains.

I don't think your water intake is excessive. Most people I know routinely drink 2.5 to 4 liters per day in the mountains.