At the beginning, the circulation of energy through the micro and macro channels in inherently linked to the breathing mechanism with no distinction between the two. Breathing-in and the energy rises-up the spine – and breathing-out the energy flows down the centre of the front of the body – with a continuous circulation under and through the groin area and over the top of the head (and through the upper and lower mouth via the ‘tongue’). This is all correct and mostly well-known – although the quality of instruction between Maser and Disciple defines the ‘strength’ and ‘purity’ of the practice.
Eventually, when the ‘still’ mind is absorbed into the ‘expansive’ mind, this marks a change in the frequency of energy-flow through the inner and outer mind and body. Things have permanently changed – but the change can be defined and logically explained. This shift in depth of perception indicates that the previous dichotomy of mind and body (micro and macro) disappear and no longer exist. However, the ‘breath’ and ‘energy-flow’ do not integrate in this way. In fact, the breath ‘separates’ from the energy-flow and is understood to have no direct connection with it. Yes – the breath can serve as a physical mechanism that links the ‘will’ of the mind to the faculty of energy-flow – but this is because the individual has not yet been trained in the true-nature of vital energy-flow.
Vital energy force flows irrespective (and quite separate) from the breathing mechanism that manipulates its circulation in the early stages of Daoist self-cultivation. The ‘turning of the water-wheel' is a very advanced practice when the breathing mechanism is disengaged from the vital energy-flow. At this level, ‘vital energy’ is understood to be a ‘psychological-physical' force that becomes ever more ‘conscious light’ as the practitioner advances in ability and age. This ‘conscious light’ manifests in the mind and body and outside and around the body! It is the all-healing and wholesome energy-field which defines physical existence and into which a practitioner transitions at the point of physical death!
Turning the water-wheel evolves away from the relatively primitive manipulation of the breathing mechanism, and transitions into a deep, pulsating rhythm permanently functioning behind all biological processes. A practitioner no longer ‘wills’ its activity – but rather enters a profound state of awareness which reveals the already existing vital energy-flow that needs no assistance to function once the mind and body have been purified and cleared of all imbalances through the foundational practices. Breathing deeply, exercising regularly and eating properly can all build the strength of the vital energy flow – but only neidan can purify the body of impurities and prepare the mind to perceive the empty nature (shen) of reality! Stilling and expanding the mind is itself the purifying of the foundational ‘eight’ meridians and indicative of a transition toward the ‘awareness’ that defines ‘Immortality’.
Although ‘sweating’ exercises are used to purify the body of excessive ‘yin’ - and can assist in the curing of long-term illnesses and injuries, etc – sweating in and of itself does not spiritually develop the individual to point of attaining the perception of ‘Immortality’! It is simply a step along the way that some need. My father is 78-yesrs-old and we can see an aura of light around him! He says that he is 78% ‘light’ and only 22% physical body! He is moving toward giving-up his body completely in due course by transitioning into a perfect expression of light! This is when the life-forces separate completely from superficial matter and assume their purest form. This is when the Water-Wheel (and its ‘turning’) dissolves completely into ‘light’!