Cardiac risk factors were evaluated in 48 persons (39 males, 9 females) with quadriplegia or paraplegia, resident in a specialized spinal injury hospital and seen 0.3 +/- 0.7 years after their spinal injury. The majority of the patients reported being extremely active physically prior to injury. Limited activity in the hospital involved the use of ergometers, pulleys, and weights; however, the majority of subjects expressed a wish for more exercise. Serum lipid profiles showed a relatively normal total cholesterol (mean 4.58 +/- 0.77 mmol/L), a very low high-density lipoprotein-cholesterol (0.91 +/- 0.27 mmol/L), a relatively normal low-density lipoprotein-cholesterol (2.86 +/- 0.68 mmol/L) and high triglycerides (1.89 +/- 0.88 mmol/L). Resting blood pressures were normal. The percentage of smokers (25%) was similar to the percentage of smokers in the general population, but many had quit smoking subsequent to hospitalization. Family histories and diet gave no evidence of increased cardiac risk. We conclude that individuals who sustain a spinal injury do not have a large inherent risk of cardiac events. In persons with paraplegia, cardiac problems develop mainly from the cumulative impact of reduced physical activity and a resulting adverse lipid profile. There may also be a reactive deterioration in other aspects of personal lifestyle, such as cigarette smoking after leaving the hospital. In high-level lesions, factors such as hypertension and a poor stroke volume with compensatory tachycardia may increase cardiac work rate during attempts at ambulation, further predisposing an individual to myocardial ischemia and cardiac arrest.