There are some breathing exercises intended to absorb large amount of prana or Chi, open the chakras and develop psychic powers. You have to breath in rhythm, different books on the subject presents different sequence .
We advise to choose a rhythm that you can accommodate and follow. There are simple breathing and some are more complex the complex techniques are dangerous, you need someone experienced to do them with you.
Here is a not too complicated exercise, lying flat on the floor or bed, completely relaxed, with hands resting lightly over the Solar Plexus (over the pit of the stomach, where the ribs begin to separate), breathe rhythmically. After the rhythm is fully established, will that each inhalation will draw in an increased supply of prana or vital energy from the Universal supply, which will be taken up by the nervous system and stored in the Solar Plexus.
At each inhalation, will that the
prana or vital energy is being distributed all over the body, to every
organ and part; to every muscle, cell and atom; to nerve, artery and
vein; from the top of your head to the soles of your feet; invigorating,
strengthening and stimulating every nerve; recharging every nerve
centre; sending energy, force and strength all over the system. While
exercising the will, try to form a mental picture of the in rushing
prana, coming in through the lungs and being taken up at once by the
Solar Plexus, then with the exhaling effort, being sent to all parts of
the system, down to the finger tips and down to the toes. It is not
necessary to use the Will with an effort.
Simply commanding that
which you wish to produce and then making the mental picture of it is
all that is necessary. Calm command with the mental picture is far
better then forcible willing, which only dissipates force needlessly.
The above exercise is most helpful and greatly refreshes and strengthens
the nervous system and produces a restful feeling all over the body. It
is especially beneficial in cases where one is tired or feels a lack of
energy. (Source)