Conquering Sleepiness in Afternoon

You feel sleepy in the afternoon in the office, but was drinking a cup of coffee.
To cope, try the following technique.

Breathe in and pull the stomach inward. Exhale through the mouth with the chin pushed forward, taking out a loud noise.
Repeat again.

Breathe in increasing levels of oxygen that generates energy in the blood.
Exhaled breath is hard to remove carbon dioxide from the body.
You'll get the energy needed to complete the task.