2和3，腿抽筋和缺这几个东西，水里面需要添加东西，REI里面有卖的；出去hiking最好3，5人有一两个经验丰富的

Electrolyte	Average amount per 2 lbs of sweat, about 1-quart	Food reference
Sodium	800 mg (range 200-1,600)	nearly any packaged food
Potassium	200 mg (range 120-600)	2 tbsp sunflower seed = 240 mg
Calcium	20 mg (range 6-40)	1 tbsp chia seed = 170 mg
Magnesium	10 mg (range 2-18)	1 tbsp peanut butter = 25 mg

Most muscle cramps are caused by sodium losses rather than magnesium and potassium because we lose more sodium in sweat than the other electrolytes