Another thought on using blood (or offal, bloody meat etc.) as a food source when you are dehydrated... it is generally suggested by those who should know that you do not eat when you have little water resources. Digestion and defecation tie up and remove needed moisture from your body. In other words, you are better off conserving what water you do have in your body than using it to gain nutrition.
I suppose we all have a built in "still" for condensing water from urine. Just hold off peeing as long as you can and your body will concentrate the urine to a high saturation point of waste products.
I have worked outdoors in a high humidity/high heat environment for years. I know this doesn't make me an expert on hydration, but I know what seems to work for me. Most of my "regimine" is conservation technique.
1. I wear light colored (tan) cotton blend clothing. It absorbs less solar heat than darker clothing and promotes evaporative cooling when soaked with sweat. Heavy jeans just get heavy and still hot because of their darker color. In this case, "cotton kills" doesn't apply like it does in cooler climates.
2. I don't eat much except a light breakfast, and even then usually some simple sugars which don't require much digestion for the energy provided. Very little if anything for lunch. Supper, after the workday is finished, heat is not an issue and plenty of water is available is when I eat my main meal of the day.
3. I "tank up" early in the day before heat/dehydration becomes an issue and I try not to urinate just because I have the "urge". I replenish my liquid often (when available) in very small but frequent amounts rather than flooding my gut all at once.
4. Seeking shade to conserve body moisture is a good idea, but not normally possible for me in my work. However, with some thought, I can sometimes plan my workday to take advantage of morning and evening shadows and so at least partially reduce my exposure to direct sunlight. I've also been know to work early, quit at midday when it is getting hottest, and return to work late afternoon when peak temperatures begin to drop. In extremes, I have been known to sleep out the day entirely and work at night.
Think about applying this to wilderness travel. And note that I am not versed in arctic survival, nor extreme desert survival. But I think the premise of "conserve what moisture you have" still applies wherever you find water scarce.
