Cardio Before or After Weights?
Updated
Short answer
Do whichever matters most to you first. If strength or muscle is the priority, lift first and do cardio after, or on a different day. Combining both is fine: a meta-analysis found the interference with strength and muscle gains was linked mainly to running, and grew with how often and how long the cardio sessions were. Cycling interfered less.
What the research says
Wilson and colleagues pooled studies of "concurrent" training (cardio and weights together). Adding cardio reduced gains in muscle size, strength and power compared with lifting alone, and the effect grew with how often and how long the cardio sessions were. Running interfered more than cycling.
For most people training for health, the trade-off is small and doing both is far better than choosing one. The WHO recommends both aerobic and muscle-strengthening activity each week.
Quick guide
| Your main goal | Order | Tip |
|---|---|---|
| Strength or muscle | Weights first | Keep cardio moderate; cycling or rowing interferes less than running |
| Endurance (running, cycling) | Cardio first | Lift after, or on easy days |
| General fitness | Either | Pick what you will stick to; alternate if you like |
| Fat loss | Either | Total weekly activity and food matter more than order |
Separate them if you can
Many coaches put cardio and weights in separate sessions, several hours apart or on different days, to limit any interference and so each session gets your best effort. A short, easy cardio warm-up before lifting is fine either way.
Frequently asked questions
Does cardio kill gains?
No. Large amounts of hard running can blunt strength and muscle gains a little, but moderate cardio alongside lifting is fine and good for health.
Should I do HIIT or steady cardio with weights?
Both work. HIIT is time-efficient but adds more fatigue, so avoid hard intervals right before heavy leg days.