Millions of people in the world jog for exercise. For the most part, jogging can be a healthy way to stay fit. However, problems can also develop for those who jog in the heat. Excessive sweating can lead to electrolyte loss that could be life-threatening. Early symptoms of electrolyte deficiency can include nausea, fatugue, and dizziness. If not treated, individuals can experience muscle weakness and increased heart rate (which could lead to a heart attack). Many sports drinks can be consumed to restore electrolytes quickly in the body.
Dave was training cycling race that was in only a few weeks. Since the marathon was coming up soon Dave decided to go for a run despite the heat wave. After about 45 minutes Dave was sweating a lot and was feeling nauseous and dizzy. He decided to stop for a break and have some of the sports drink he had brought along.  After a little while he was feeling better and headed home.
what was causing Dave to lose electrolytes?