It is believed that the mechanisms of aging or longevity are multifactorial. We selected four major postnatal factors to verify the mechanisms of longevity and aging. Type B behavior is strongly associated with longevity. The frequency of Type B behavior pattern (55.5 vs. 26.6%) was significantly higher while Type A behavior pattern (2.4 vs. 5.9%) was much lower in the longevity group compared with those in the elderly group (P < 0.01). The decline of arterial partial pressure of oxygen (PaO2) might relate to the aging process which was supported by two facts: (1) low PaO2 might lead to high frequency of chromosomal aberrations, the frequency of chromosomal aberrations was 1.22+/-0.53%, 0.57+/-0.23% and 0.23+/-0.22% in PaO2 < 75, 75-84 or > or = 85 mmHg groups respectively (P < 0.025); (2) the lower the PaO2, the more serious the retina arteriosclerosis. Five mean contents of superoxide dismutase (SOD) in erythrocytes were 626+/-39, 583+/-56, 556+/-43, 547+/-49 and 557+/-40 microg/gHb in different age groups. No significant differences were found in the longevity group as compared with those in 40-89 years old age groups (P > 0.05), but a significantly lower level was found in the middle rather than the young age group (P < 0.05). The studies of thixotropy show that micro-blood-flow state also sustains a better condition in the longevity group. We consider Type B behavior pattern, a higher PaO2, a better micro-blood-flow and a higher level of SOD of erythrocytes may be beneficial for longevity.