Effects Of Indoor Or Outdoor Moderately Heavy Superset Resistance Training On Pulmonary Measures

The American College of Sports Medicine has determined that resistance training (RT) and outdoor activities are two of the top ten worldwide fitness trends for 2023. We previously found that RT outdoors (OUT) had reduced perception of effort than indoor RT (IN), despite no physiological differences in heart rate or energy expenditure. It is unknown whether these findings extend to respiratory values, and as such, pulmonary measures need to be evaluated. PURPOSE:To assess whether indoor or outdoor environments effect pulmonary responses. METHODS: Twenty-three adult participants completed the study (n = 10 female, n = 13 male; age: 26.1 ± 8.8 yrs; height: 172.2 ± 9.5 cm; mass: 73.4 ± 18.7 kg; RT experience: 5.3 ± 4.8 yrs). Participants were all equipped with a COSMED K5 wearable metabolic system attached through a harness securely on the back. Outcome measures included ventilation (VE [L/min]), tidal volume (VT [L]), and respiratory frequency (Rf [breaths per min]). Randomly in indoor and outdoor settings, participants completed 4 supersets of the reverse lunge and shoulder press exercises. Data were analyzed using a paired t-test with significance accepted at p < 0.05. Effect size was determined by Cohen’s d, with interpretation of small (d = 0.2), medium (d = 0.5) and large (d = 0.8). RESULTS: Significant differences were observed for VE (IN = 45.0 ± 15.8; OUT = 47.1 ± 16.5 L/min, p = 0.021, d = 0.13 [small]). However, there were no differences observed for VT (IN = 1.7 ± 0.6 vs. OUT = 1.7 ± 0.7 L, p = 0.30, d = 0.157 [small]) and Rf (IN = 27.9 ± 5.8 vs. OUT = 28.8 ± 6.2 breaths per min, p = 0.24, d = 0.16 [small]). CONCLUSIONS: Exercising outdoors at the same intensity has no effect on some pulmonary measures (VT, Rf) but has an effect on others (VE). Increased pulmonary ventilation occurs in outdoor versus treadmill running, and the present findings extend this observation to RT. Future studies should be designed to determine the underlying mechanisms behind this phenomenon.