Concurrent Exercise Training Adaptations Over 4-Months in Sedentary, Middle-Aged Adults With and Without Post-Exercise Peanut Consumption

Maximizing exercise training adaptations in high level athletes requires complex coordination of training load, nutrition, and recovery, however, achieving beneficial health adaptations in middle-aged adults does not require the same complexity. Simple workouts and nutrition options might convey the health benefits with minimal burden to this reluctant population. Health guidelines recommend concurrent, aerobic and resistance, exercise sessions several times per week. Middle-aged adults who meet these recommendations might benefit from a simple, inexpensive, and readily available whole food as a post-workout snack to augment normal cardiorespiratory and strength adaptations. Peanuts, an inexpensive and accessible food, have a protein and carbohydrate content that might support training-induced health benefits, while their micronutrients and healthy fats might confer additional advantages. The purpose of this study was to determine whether the consumption of peanuts post-exercise had an effect on aerobic and resistance training adaptations in middle-aged adults. We hypothesized that adding peanuts as a post-exercise nutrition source would improve muscle strength, lean mass, cardiorespiratory fitness, and exercise tolerance to a greater extent than a standard carbohydrate-based snack. Seventeen, untrained individuals between 30-55 years old completed the 4-month concurrent training program, which included resistance exercise (2x/week) and aerobic exercise (2x/week). Participants were randomized into two groups: one group received a peanut-containing smoothie (NUT) after each workout, and the other an isocaloric, non-peanut carbohydrate-based smoothie (CON). Body composition, cardiorespiratory fitness, and strength measures were completed before and after the 16-week exercise training program. Total lean mass increased 4% (p = 0.008) pre- to post-training (CON 43.7 ± 6.7 kg to CON 45.5 ± 7.1 kg and NUT 43.6 ± 11.3 kg to 45.4 ± 13.5 kg) along with significant increases in upper-body and lower-body strength as assessed by 1-repetition maximum and isometric strength tests. Lean mass and strength gains were not significantly different between groups. Cardiorespiratory fitness (VO2 peak) increased significantly with training (p = 0.02), but there were no significant differences between groups (CON 30.6 ± 2.8 ml/kg/min to CON 34.6 ± 6.6 ml/kg/min and NUT 29.7 ± 5.5 ml/kg/min to 32.0 ± 8.0 ml/kg/min). Exercise tolerance also improved significantly with training (p < 0.001) with no significant differences between groups after 16 weeks (CON 350 ± 155 s to CON 693 ± 262 s and NUT 338 ± 107 s to 854 ± 423 s). Despite the higher fat content of peanuts, there was no difference in fat mass pre- to post-training, nor between groups. This suggests that even though peanuts do not augment training adaptations more than a standard carbohydrate-based post-exercise snack, neither do they detract from gains in muscle strength, lean mass, and cardiorespiratory fitness. In fact, lean mass gain was comparable to that observed in similar training/protein supplementation studies in middle-aged adults. Thus, peanuts can be considered a suitable post-workout option without attenuating the health benefits of exercise training. Southwestern University Summer Undergraduate Research Fellowship and The Peanut Institute Scholars Fund. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.