The influence of aerobic variables on mixed martial arts (MMA) performance is currently unknown. This study aimed to compare the laboratory-measured aerobic variables of MMA participants to the external load and intensity of MMA sparring bouts to determine the effect of aerobic capacity on performance. Ten participants (age = 24 ± 2.8 years; mass = 74.3 ± 8.2 kg; stature = 176.8 ± 7.9 cm) completed the following: a treadmill-graded exercise test to measure V̇Omax, VT and VT; 3 × 5 mins sparring bout equipped with a Catapult Optimeye S5 accelerometer recording Playerload (PLd) and Playerload per minute (PLd∙min), with a sessional rating of perceived exertion (sRPE) recorded as internal intensity. Median V̇Omax (53.3 ml∙kg∙min) was used to split the cohort into the top 50% and bottom 50%. Pearson's r correlations (BF ≥ 3) were calculated between GXT and sparring variables. V̇Omax (53.1 ± 5.9 ml∙kg∙min) was found to have very large ( ≥ .70) linear relationships with PLd (161.4 ± 27.2 AU) and PLd∙min (10.7 ± 1.8AU). The top 50% group maintained moderate sRPE (4-6AU) and greater PLd∙min throughout the bout, with the bottom 50% group's sRPE moving from moderate to high (>7AU) indicating V̇Omax <53 ml∙kg∙min is related to increased internal intensity. These data support the aerobic nature of MMA and may provide aerobic capacity targets for athletes and coaches to aim for during competition preparation.