Recently, a client asked whether she should do weighting lifting exercises before cardio or cardio before weights. Generally, if you are going to do both types of workouts on the same day, it’s accepted that you should start with weights.
Lifting weights first means your muscles aren’t fatigued when you start your training, and weight lifting wakes up your body so that you can perform efficiently when you move to your cardio workout. It usually takes about 15-20 minutes for the body to start reaping the benefits of a cardio workout, so consider weight lifting as a little warm-up.
Another option is to alternate days–cardio three times a week (M,W,F), weight training three days a week (T, TH, Sat).
Just keep in mind that you need both, but whatever you are doing towards becoming physically fit is beneficial. If for some reason you prefer to do cardio followed by weight lifting, and you can’t get motivated to workout in the reverse order, it’s better to workout then skip cardio all together because you don’t like the format. When exercising you have to find what works for you and your body. You need to feel good. Everyone’s time is limited, so try your best and build slowly.