This article is the first of four to explore the effects of age-related changes in impairment evaluations as defined by the fifth and sixth editions of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). With respect to the cardiovascular system, impairment ratings for the following conditions commonly are affected by the aging process: coronary artery disease, valvular heart disease, arrhythmias/dysrhythmias, hypertension, and peripheral vascular disease. Impairment ratings in the fifth and sixth editions of the AMA Guides for the pulmonary system apply corrections for age with respect to certain measurements such as forced vital capacity. The normal aging process does not significantly affect impairment ratings for either hematological impairments or the endocrine system, nor does normal aging significantly affect the impairment ratings for mammary glands. With careful attention to the diagnosis and causative factors, evaluators may find that the normal aging process can affect impairment ratings associated with metabolic bone disease. Evaluating physician typically must determine impairment secondary to a specific cause (eg, injury or exposure) and therefore must consider if other factors are contributing to the impairment.