Eserhaut, DA, Fry, AC, Stone, MH, and Kraemer, WJ. Acute endocrine responses with long-term weightlifting in a 51 year old male weightlifter. J Strength Cond Res XX(X): 000-000, 2024-To study the effects of long-term (>35 years) competitive weightlifting on acute endocrine activity, a 51-year-old male two-time Olympian in weightlifting (Subject A) was compared with highly trained young male weightlifters (controls, n = 23; age = 17.7 ± 0.3 years). Between 1400 and 1700 hours, subjects performed 15 maximum effort vertical jumps, a series of single repetitions of the snatch progressing to a maximal effort, and 3 × 10 snatch pulls at 60% 1 repetition maximum. Blood sampling occurred at 0700 hours, pre-exercise, and +5 and +15 minutes postexercise. Exercise performances were comparable between Subject A and controls and elicited similar lactate responses at +5 minutes (mmol·L-1; A = 9.2; controls = 8.1 ± 0.4). Resting testosterone at 0700 hours was lower for Subject A than for the controls (nmol·L-1; A = 13.9; controls = 25.4 ± 2.0), although acute responses at +5 minutes were comparable (A = 21.6; controls 18.3 ± 1.5). Cortisol responses (nmol·L-1; A = 468.4, controls = 540.6 ± 32.3) and testosterone:cortisol ratio (A = 0.0461; controls = 0.0376 ± 0.004) were similar at +5 minutes. Subject A showed no 22 kDa growth hormone response at +5 minutes, while controls exhibited a substantial increase (µg·L-1; A = 0.4; controls = 16.7 ± 2.6). β-endorphin responses were no different at +15 minutes for Subject A relative to controls (pmol·L-1; A = 30.1; controls = 33.8 ± 3.7). Resting and exercise-induced endocrine physiology is partially modified with aging despite long-term participation in competitive weightlifting. Importantly, Subject A's testosterone response was largely preserved.