It depends on the case; there is no single guideline.
Effect by goal · level of evidence
Strength and hypertrophy gains
harmsModeratemeta-analysis (AAA)
Meta-analysis of 21 studies: combining a lot of cardio with strength training ('concurrent training') reduces gains in strength, power, and hypertrophy compared with strength training alone (interference effect), especially with greater cardio volume and duration.
Strength and hypertrophy gains — harms (Moderate, meta-analysis). Meta-analysis of 21 studies: combining a lot of cardio with strength training ('concurrent training') reduces gains in strength, power, and hypertrophy compared with training strength alone (interference effect), especially at higher cardio volume and duration. 22002517
Information, not medical advice. Prescription drugs require a doctor.
Information, not medical advice. Scientific evidence reflects the quality of the studies.