The purpose of this study was to determine the effect of the musical tempo on heart rate (HR), rating of perceived exertion (RPE), and distance run (DR) during a treadmill aerobic test in young male and female adults. Participants ran on the treadmill listening to music at 140 beats per minute (bpm; M₁₄₀), 120 bpm (M₁₂₀), or without music (NM). No significant sex differences were found on HR (M₁₄₀ = 172.6 ± 12.7, M₁₂₀ = 171.9 ± 11.1, NM = 170.1 ± 12.2 bpm, p = .312), RPE (M₁₄₀ = 7.5 ± 1.4, M₁₂₀ = 7.6 ± 1.3, NM = 7.6 ± 1.2, p = .931), or DR (M₁₄₀ = 4,791.4 ± 2,681.1, M₁₂₀ = 4,900.0 ± 2,916.9, NM = 4,356.1 ± 2,571.2 m, p = .715). Differences were found in the effect of tempo on HR between condition M₁₄₀ and NM (172.6 ± 12.7 vs. 170.1 ± 12.2 bpm, p = .044, η² = 0.32). In conclusion, musical tempo does not affect performance, physiological, or perceptual variables in young adults exercising on a treadmill at a constant speed.