Objective:　Although　the　cardiac　benefits　of　maintaining　a　lifelong　exercise　routine　are　undisputed,　to　what　extent　late-in-life　exercise　training　can　ameliorate　cardiac　aging　remains　unclear.　We　examined　the　impact　of　a　12-month　exercise　training　program　on　cardiac　reserve,　static　cardiac　structure,　and　cardiac　function　in　older　adults.　Design:　This　study　was　a　single-center,　randomized　trial　using　Zelen　design.　Participants　in　the　centerbased　exercise　(CBE)　group　underwent　an　individualized　multicomponent　exercise　training　program.　Setting　and　Participants:　In　total,　120　community-dwelling　older　adults　aged　65-85　years　were　evenly　divided　into　a　CBE　group　and　a　control　group.　Methods:　The　primary　outcome　indicator　was　absolute　change　in　peak　oxygen　uptake　(peakVO2)　per　kilogram　from　baseline　to　12　months.　The　secondary　outcome　indicators　were　the　absolute　changes　in　other　cardiopulmonary　exercise　test　indices　and　cardiac　magnetic　resonance　parameters.　This　study　has　been　registered　at　the　Chinese　Clinical　Trial　Registry　Network　(ChiCTR2400081824).　Results:　In　total,　47　older　adults　in　the　control　group　and　49　in　the　CBE　group　ultimately　completed　the　12-month　follow-up　and　were　analyzed.　Of　all　participants,　52　(46.4%)　were　men,　and　the　mean　age　was　71.22　+/-　4.55　years.　The　absolute　change　in　peakVO2/kg　was　significantly　different　between　the　CBE　and　control　groups　by　+3.32　mL/kg/min　(95%　CI　2.10-4.53;　P　＜　.001),　and　a　sex-related　difference　was　observed.　Additionally,　the　right　ventricular　peak　filling　and　ejection　rate　improved　to　a　greater　degree　in　the　CBE　than　control　group　(+65.57　mL/s,　P　=　.006;　+56.39　mL/s,　P　=　.026,　respectively).　Conclusions　and　Implications:　A　12-month　exercise　training　program　started　later　in　life　was　effective　in　improving　cardiopulmonary　reserve,　and　men　showed　a　better　response　to　training　than　women.　The　right　ventricular　function　increased　after　late-in-life　exercise　training.　(c)　2024　The　Authors.　Published　by　Elsevier　Inc.　on　behalf　of　AMDA　-　The　Society　for　Post-Acute　and　Long-Term　Care　Medicine.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://　creativecommons.org/licenses/by-nc-nd/4.0/).