The primary objective of this proposal is to compare a moderate or high intensity exercise intervention to improve physical function in persons aging with HIV. Both HIV-infected and HIV-uninfected older adults will be assigned to a moderate intensity cardiovascular and resistance training intervention for 12 weeks, and then randomized to either continue moderate intensity exercise, or increase to high intensity exercise for an additional 12 weeks. The primary outcome is the impact of exercise on physical function, as measured by the overall score of a modified Short Physical Performance Battery (mSPPB) and the chair rise time from the mSPPB. The secondary outcomes include changes in insulin-like growth factor-1 (systemic and local) and inflammation (interleukin-6 (IL-6), soluble tumor necrosis factor receptors 1 and 2 (sTNFR-1 and sTNFR-2)).