Excessive sweating, or as its known in medical literature as hyperhidrosis, is a clinical condition where parts of the body are sweating beyond the bodies physiological needs.
There is no connection between being anxious or active because this condition can happen at times when the person is not active or anxious. This represents the autonomous nature of the sympathetic nervous system which is an involuntary one compared to the motoric or sensory nervous systems which are voluntary systems.
The very basic explanation for excessive sweating is that a segment of the sympathetic nervous system is responsible for this presentation. What is the sympathetic chain you may ask? This is an autonomous part of the nervous system on which we have no control. The autonomous nervous system has two parts to it, the sympathetic and the parasympathetic. Those systems affect blood pressure, heart rate, anxiety level and many other functions.