Of course not. Your presentation performance will be more effective if you warm up and exercise the muscles required for speaking beforehand.
As part of your presentation preparation follow these easy exercises as a vocal warm up. Practice these before and on the actual day of your delivery.
Find somewhere private a spare room or the rest rooms, allow 15 minutes to go through them:
1. Yawn, several times. Breathe slowly out through the mouth and deeply in through the nose between each one.
2. Pull faces, in private not in front of clients or colleagues! Mimic emotions; sad, angry, happy, surprised etc.. Stretch your face.
3. Poke your tongue out, then up and down and side-to-side.
4. Whisper and then get louder five times:
The tip of the tongue, the lips and the teeth.
Notice where your tongue moves to and how your lips and mouth moves.
Then say again five times starting slowly and then getting quicker:
5. Say the following: BOO, BOH, BAW, BAH, BAY, BEE.
Then replace the B with a D, then K, R, S, T and finally Z. If you have time try F, G, H and P too.
6. Roll your shoulders forward five times and then back five times. Then place your shoulders towards your elbows.
7. Lift your chest and leave it there ladies you will know what I mean here!
8. Breathe in slowly and then out slowly.
9. Smile gently inside and out, your audience and go present!