Deciding whether to do cardio before or after lifting weights depends primarily on your specific fitness goals, according to exercise physiologists, because scientific studies show that exercise order produces minimal physiological differences for general fitness. According to Luke Carlson, founder and CEO of Discover Strength, studies rarely show that the sequence matters mechanistically, while Alex Rothstein, an exercise physiologist and coordinator of the Exercise Science program at New York Institute of Technology, notes that the difference is minimal enough that personal preference can dictate the routine.
Prioritizing Cardio vs. Weights Based on Training Goals
If you are training for a specific event like a half marathon, Carlson advises tackling cardio before strength training. Performing running workouts while fatigued from lifting compromises your ability to hit targeted paces during tempo runs or interval sessions. Conversely, if you want to hit a specific strength benchmark, Carlson recommends starting in the weight room so fatigue does not inhibit your lifting performance.
According to findings from a 12-week study cited in fitness research, participants who lifted weights before cardio experienced greater total body fat and visceral fat loss, became more active overall with higher daily step counts, and improved muscular endurance and explosive strength compared to those who started with cardio. Cardiovascular fitness improved similarly in both groups, indicating that heart health benefits remain consistent regardless of exercise sequence.
Why Exercise Sequence Affects Fat Loss and Fatigue
When resistance training begins, the body relies on muscle glycogen as its primary fuel source. As those stores deplete, the body shifts to utilizing fat for energy. Moving into a cardio session immediately after lifting leverages this metabolic shift, making fat a larger fuel source and explaining the greater fat loss observed in weights-first routines, as supported by a 2022 systematic review showing resistance training significantly reduces visceral fat.
Pro Tip: Separate your lifting and cardio sessions into different workouts when possible. Rothstein points out that fatigue increases injury risk by worsening form, and full-body stabilization requires core and lower-body engagement even during upper-body lifts.
Frequently Asked Questions
Does doing cardio before lifting kill your muscle-building gains?
Tiring yourself out on cardio may impact your ability to lift heavier weights for personal records, but Carlson notes it will not sabotage your overall muscle-building goals.
Is it better to combine cardio and strength into one session?
When time constraints prevent split sessions, combining them into one workout is effective. If you follow a single session, Carlson and Rothstein suggest starting with weights for strength goals or starting with cardio if endurance racing is your primary focus.
Why does fatigue increase injury risk during combined workouts?
According to Rothstein, fatigue degrades exercise form. Even when targeting isolated muscle groups, the nervous system, core, glutes, and quads recruit heavily to stabilize the body, compounding systemic fatigue.
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