Our physical body does not require "pain for gain" exercises which encourage our fight or flight response and compress the muscles, tighten tendons, stiffen joints and acidify the blood and tissues with excess lactic acid, carbon dioxide and other metabolic waste. After age 30, these types of exercises gradually become more harmful. Qigong exercises in contrast involve stretching and toning the muscles and tendons, using slow, gentle harmonious movements which loosen and limber the joints and ligaments. The flexibility of the body's moving parts are increased and strengthened. The internal organs and glands are stimulated with deep therapeutic massage provided by the contraction and expansion of the diaphragm. At the same time, the blood and inter-cellular fluids are oxygenated and alkalized rather than carbonated and acidified. The endocrine system is balanced rather than excessively flooded with adrenaline and the nervous system is relaxed instead of overworked.