How to overcome tiredness while conducting session.

Why do some people feel lots of stress and tired while conducting sessions…………….Conducting presentations is something I like to do. Yet it is sometimes taxing as it creates lot of anxiety, tiredness. Why does that happen? When a person is talking his thoughts, his breath, his speech, his actions, all have to fire in sync. Many a times this sync us lost. The mind moves faster while the tongue isnt moving that fast to catch up, the breath isnt in adjusting to the speech. That creates stress for the body since it is trying to pick up the speed of thoughts which is a tough job.How can this be overcome?1. Stop. Take 3 deep breaths. Drink some water. This helps to slow down the thoughts as one de focusses.2. Then affirm that my thoughts are evolving at a speed that my body can accept and both are now married to go together.3. Re set the pace of speech.4. Focus back to the subject.