Energy is described in Western culture as vigor, life, spirit, passion, power, and electromagnetism.
The Hindus call vital energy prana. The Hebrew name for "vital energy" is ruah. The Chinese define energy as life force, or chi.
Prana is physical, mental, and spiritual energy in Hinduism.
It is believed that prana is the fundamental energy and the source of all knowledge. By practicing yoga, prana continuously flows inside us, creating vitality in our bodies. Too little prana in the body can be expressed as a feeling of being stuck. You would have a lack of motivation, lack drive, and be depressed.
When you lack prana, or vital energy, you may become ill.
This philosophy believes that your state of mind is directly linked to the amount of prana within us. The more balanced and peaceful a person is, the more prana is inside your body.
The more imbalanced or stressed you are, the more diluted the prana, or vital energy, is within your body. Prana is power, and the more you develop your breathing practices the more power you will experience.
Chi, in Eastern medicine, is the vital energy that flows though each organ and system of the body. All of these organs and systems are connected by this vital energy so if an organ is sick you must look at the entire body to find the cause of illness.
This chi, or energy, is found at a molecular level. Western medicine would call this vital energy "electromagnetism," which holds the atoms in orbit around each other in your body.
Chinese medicine works on the construct that when your body is sick, your chi, or energy, is out of balance and the flow of vital energy must be restored to a healthy flow.
The way I describe this to my clients and patients is to imagine your body as a home that is wired with electrical wiring. Your body's electrical system is just like your home:
Sometimes there is a short in the circuit or a loose wire. You call your electrician to get the flow of electricity going again.
In Chinese medicine you can go to an acupuncture practitioner or practice tai chi or Qigong for the same effect.