Hydration Requirements Backpackers, Hikers, Cyclers
Dehydration:
- Increases heart rate
- increases cardiovascular strain
- slows body’s ability to dissipate heat
Requirements are not as complicated as for nutrition, but again needs vary due to several factors:
- temperature and humidity
- sweating
- panting
- activity level
General base requirements:
Formulas abound, I will give you three:
- Weight ÷ 2 = number of ounces you should drink: moderate temp, humidity and activity
example: 140# ÷ 2 = 70 ounces
- For each twenty-five pounds of weight = 8 ounces water : mild temp, humidity, activity
example: 150# ÷ 25 = 6-8ounce glasses Please note this covers mild everything, take it into consideration
- old 8X8: 8-8 ounce glasses per day
Also keep in mind the body processes ingested fluids at the rate of 1/2 ounce per minute, that is about 8 ounces per 15 minutes.
These formulas take into account the supposition you will receive 20% of your hydration needs from the food you eat. If using dehydrated or freeze dried foods needs may increase.
Variables
The variables below are a guideline to help you adjust
-
Temperature and humidity
- cold/ dry + +
- cold/ humid +
- hot/ dry + + +
- hot/ humid + +
-
Sweating, panting, breathing through the mouth, activity level
- sweating profusely + +
- Panting +
activity level determines sweating and panting
Overhydration
This report would not be complete without a warning about hyponatremia which is low blood sodium levels. It is possible to overhydrate, especially when sweating is a factor. Your sport drinks should help you here. Do not take the symptoms lightly as it can lead to death.
Symptoms of hyponatremia:
- Nausea and vomiting
- Headache
- Confusion
- Lethargy
- Fatigue
- Appetite loss
- Restlessness and irritability
- Muscle weakness, spasms or cramps
- Seizures
- Decreased consciousness or coma
The line is not so fine that it is easily crossed over, but please be aware. It has become a major issue for marathon participants.
A post about securing safe drinking water for backpacking.
