Do your weights workout first
Experts say weight training should be done first, because it’s a higher intensity exercise compared to cardio. Your body is better able to handle weight training early in the workout because you’re fresh and you have the energy you need to work it.
Conversely, cardiovascular exercise should be the last thing you do at the gym, because it helps your body recover by increasing blood flow to the muscles, and flushing out lactic acid, which builds up in the muscles while you’re weight training. It’s the lactic acid that makes your muscles feel stiff and sore.