What can be done if one is too drowsy or tired while practising?
Practising Qigong does free oneself of many thoughts, which are making one restless and thereby one achieves a pleasant, relaxed state. The mental activity is being reduced, the brain is working less, the body relaxes and the mind is calm. All this are good conditions for falling asleep. Drowsiness or fatigue often occurs with beginners, when they start to practise physically and mentally exhausted.
If one is not able to respond effectively to drowsiness or fatigue, one should take a break practising and move a bit, massage the face or tap the body. If those measures also do not help one may practise exercises in motion or drink a bit of warm water.
The quiet state of Qigong does differ significantly from the sleeping state. In order for the exercise to be effective, one should avoid to fall asleep while exercising. However people, who suffer from insomnia, may well use the effect therapeutically to facilitate falling asleep.