Should I do cardio before or after lifting weights?

Lift first, then do cardio, if getting stronger or building muscle is your main goal. Do cardio first if you're training for a run, ride or race. Whichever one you care about more should get your freshest legs and best energy.

Why weights usually go first

Heavy lifting needs focus, coordination and fresh muscles. If you run hard for 30 minutes before squatting, your legs are tired and your form gets worse, which raises injury risk and cuts the weight you can lift. Cardio at an easy to moderate pace is much less affected by being tired from lifting.

When cardio goes first

If you have a long run or a hard interval session planned, treat the lifting as the extra. Doing legs before a hard run is a bad trade, and you'll run worse and lift tired.

The easy way to handle this is to keep the priority session on its own day when you can.

Short cardio as a warm-up is fine

Five to 10 minutes of easy cardio before lifting is a normal warm-up and won't hurt your session. That's different from a full cardio workout. It just raises your temperature and gets blood moving. Here's a full warm-up routine.

Best option: separate them

If your schedule allows it, do cardio and lifting at different times of day, or on different days. Research suggests that putting 6 or more hours between them reduces interference, but even a gap of a few hours helps. Many people just do lifting 3 days a week and cardio on the other days, which works well.

Some simple setups:

• Lifting days: weights first, then 10 to 20 minutes of easy cardio if you want it
• Non-lifting days: longer or harder cardio
• Running goal: hard runs on their own days, lifting after an easy run or on a separate day
• Tracking both: League of Fitness syncs lifting sessions and cardio from Apple Health and scores them by intensity and heart rate zones, so the order you choose doesn't cost you credit for either one

Does cardio ruin muscle gains?

Not at normal amounts. Moderate cardio doesn't get in the way of muscle growth for most people, and it's good for your heart. The interference mostly shows up when someone does a lot of hard running on top of heavy leg training. There's more detail in does cardio kill gains.