It is not necessary that transfer of energy is always in positive form. This means negative energy can enter into a Sattvik person without any warning .
Nature and working pattern of energy of spiritual person is different from the person’s who are involved in the worldly affairs. Satvik person and at the start of Sadhna, energy is very sensitive, fragile and catches every kind of energy comfortably. Because of this any kind of negative energy damages the Aura easily. Use of harsh words, any kind of negative thoughts, indiscretion in eating habits and impurity of place etc affect a hermit/sadhak to a great extent.
In contrast to positive energy, Negative energy has low frequency because of which it enters, expands and becomes permanent easily. This is the reason that transformation and displacement of negative energy is not a cake walk.
Many times it happens that energy flows downward automatically like water flows downward without specific process from high point.
Life force is subtle and sensitive. There are many factors which can affect spiritual energy. Touch, taste, vision/form, smell , sound etc affect this energy but mental conditions influence utmost.For example if someone’s outer appearance is good but thought process is not good than touch of this person will transfer only negative energy. While cooking if mind is not in positive state than the satvik power of food gets decreased.
A person who has been thinking all day long about negative incidence, people and things, can affects the postive energy without saying a word. This happens due to continuous repetition of negativity which makes negative energy stronger. On the other hand due to strong grasping power of postive energy it gets affected easily even with a glance or with few words.
Mental thoughts have higher frequency than any other mean. Because of which mental condition influences greatly to outcome of any action. This is the reason emphasis on purity of thoughts is given in every spiritual path.