WATER : Drink it

  On a daily basis, the simplest way to tell if you are adequately replacing sweat loss is to check the color and quantity of your urine. If your urine is dark and scanty, it is concentrated with metabolic wastes and you need to drink more fluids.When your urine is pale yellow, your body has returned to its normal water balance. Your urine may be dark if you are taking vitamin supplements; in that case, volume is a better indicator that color is.
  Besides monitoring urine and weight loss, you should also pay attention to how you feel. If you feel chronically fatigued, head-achy, or lethargic, you may be chronically dehydrated. This condition is most likely to happen during long hot spells in the summertime. Dehydration is cumulative.
  When the weather is hot and you are losing your cool, be aware of the signs and symptoms of heat illness. Be sure to consume appropriate fluids to prevent the problem. If you fail to drink enough, don't tough it out to finish your workout. Watch for these signs:

• Muscle cramps
• Nausea, vomiting
• Headache, dizziness
• Confusion, disorientation
• Weakness, reduced performance
• Inability to concentrate
• Irrational behavior

Water ...

1. In blood transports glucose, oxygen, and fats to working muscles and carries away metabolic by products such as carbon-dioxide and lactic acid.
2. In urine eliminates metabolic waste products. The darker the urine, the more concentrated the wastes.
3. In sweat dissipates heat through the skin. During exercise water absorbs heat from your muscles, dissipates it through sweat, and regulates body temperature.
4. In saliva and gastric secretions helps digest food.
5. Throughout the body lubricates joints and cushions organs and tissues.  

Many people experience cramping. The lack of water, calcium, potassium, or sodium could be the problem. All of these play vital roles in the functions of organs and muscles in your body.