Different studies have shown benefits for both forms of exercise being first in a workout. Like other aspects of fitness, it depends on the individual’s goals and workout style.
A recent American Council on Exercise study found cardio helps moderate exercisers’ heart rates, keeping them at a safe level and reducing risk of injury. On the other hand, beginning a workout with cardio may lead to fewer repetitions in strength training immediately following a cardio session.
A good rule of thumb is to start your session with the component that aligns most closely with your goals.
For instance, if you are training for a race and aiming to increase cardiovascular endurance and speed, keep the cardio first and add a light strength session after. If your goal is to build strength and increase lean muscle mass, focus on resistance training first, when your muscles and your mind are fresh.
As you sequence your workouts, keep in mind that it is important to incorporate both no matter the order. Go with whatever is going to help you improve!