Life is hectic; we understand.
Sometimes, it’s all you can do to get any physical activity, let alone a workout program that has you in the gym two hours per day, six days per week.
In your haste to get your workouts in, you’ve likely tried combining your cardio training and weight training within the same workout.
But which should you do first, cardio training or weight training?
In this article, we’ll help you figure whether you should do cardio before or after weight training, depending on your goals.
Is It Better to Do Cardio Before or After Weights?
Most fitness blogs you come across will tell you that you should do weight training before cardio, and while that may be the right answer for most of the general fitness population, it’s not the correct answer for everyone on all occasions.
You see, the above answer lacks context and nuance.
For you to decide whether you should do cardio before or after weight training, you first need to determine what is the ultimate goal of your training.
And this brings us to the principle of specificity.
The principle of specificity dictates your training should be appropriate for the desired end goal so that you achieve the sought-after result. [ 1]
In other words, the principle of specificity states that you should prioritize those aspects of your training in which you want to excel.
So, if you want to get stronger, you should focus your training on lifting the most weight possible during training.
If you want to be able to run a marathon, you should emphasize long-distance running and building up your cardiovascular endurance.
Based on this, your goal will dictate how you structure your training.
Therefore, if building muscle and strength is your goal, you would want to do your weight training first, and then save cardio for after your workout on doing it on a separate day entirely (if you do it at all).
The reason that you wouldn’t want to perform cardio before you lift weights is that it could induce excessive fatigue in your muscles, which would subsequently cause a reduction in the amount of force your muscles are capable of generating and thereby significantly limit the amount of weight you can lift in your strength training sessions.
Conversely, if you want to get better at running or swimming long distances, it doesn’t make much sense to go and do a bunch of heavy squats and deadlifts immediately before your cardio training. Lifting heavyweight for a bunch of reps will overly fatigue your muscles, reduce their glycogen levels, and ultimately limit how long you can last in your cardio sessions before succumbing to fatigue.
This “interference” effect has been well-documented in the literature. [2,3]
Two different studies published in the Journal of Strength and Conditioning Research noted performing cardio immediately before resistance training reduced the number of reps subjects performed during resistance training, as did power output. [4,5]
Furthermore, subjects also experienced increased heart rates and rates of perceived exertion during the weight training sessions that followed cardio training.
Mostly, lifting “feels” heavier when you do a prolonged bout of cardio immediately before hitting the weights.
Is It Okay to Begin Workouts with Cardio?
At this point, we feel it’s probably a good idea to make a distinction in what we’re referring to as “cardio.”
Doing 5-15 minutes of relatively low-intensity walking, jogging, or puttering about on the elliptical isn’t going to significantly impair your lifting performance or rob you of your precious muscle gains.
So, if your definition of “cardio” is doing a few minutes of light physical activity before slinging the iron around, fret not, you can do your “cardio” and be just fine.
However, if your definition of cardio is performing 45-60-minute bouts of running, rowing, or cycling or performing HIIT sprints, that most certainly can interfere with your performance in weight training workouts and may harm your results. 
The bottom line here is that doing a few minutes of cardio before your weight training workouts will not harm your performance or results, and may benefit it. But, performing prolonged bouts of cardio training will hurt your weight training performance.
Can Do You Do Cardio and Weight Training on the Same Day?
The short answer is, yes.
Performing just a few minutes of cardio (as a warm-up) before resistance training can help increase blood flow and core temperature, which will help you perform better in your workouts.
If you do want to perform some longer bouts of cardio (30 minutes+), you’ll want to perform that ~6 hours after your weight training workouts (if muscle and strength gain is your goal) or perform it on a separate day entirely.
Furthermore, a recent review noted that:
“a close examination of the literature reveals that the interference effect of concurrent exercise training on muscle growth in humans is not as compelling as previously thought. Moreover, recent studies show that, under certain conditions, concurrent exercise may augment resistance exercise-induced hypertrophy in healthy human skeletal muscle.” 
All of those concerns about “cardio making you small” have mainly been overblown.
So long as you’re not doing egregious amounts of cardio and surpassing your maximum recoverable volume (MRV), you don’t have to worry about a little bit of cardio here and there affecting your performance or gains in size or strength.
The Bottom Line on Cardio and Weight Training
Deciding whether to do cardio before or after weight training ultimately boils down to what specific goals you want to accomplish with your training.
If you’re a coach, this means that your client’s needs and goals should drive the structure of the training program.
Weight training and cardio training provide fantastic benefits to your health and wellness.
But, some of the physiological changes induced by weight training have a directly oppositional effect to those caused by cardio training and vice-versa.
For the average person looking to add a few pounds of muscle and drop a few pounds of fat, they’re likely best served by prioritizing weight training and saving cardio for after their workout, later in the day, or on a separate day entirely.
If your cardio workouts typically last longer than 30 minutes and/or higher intensity, they can hurt muscle and strength gains if performed immediately before or after weight training.
If your cardio workouts are shorter and lower intensity, they likely won’t have as much of a detrimental effect on your performance or progress.
- Hawley JA. Specificity of training adaptation: time for a rethink?. J Physiol. 2008;586(1):1–2. doi:10.1113/jphysiol.2007.147397
- Fyfe, J. J., Bishop, D. J., & Stepto, N. K. (2014). Interference between concurrent resistance and endurance exercise: molecular bases and the role of individual training variables. Sports Medicine (Auckland, N.Z.), 44(6), 743–762. https://doi.org/10.1007/s40279-014-0162-1
- Coffey VG, Hawley JA. Concurrent exercise training: do opposites distract?. J Physiol. 2017;595(9):2883–2896. doi:10.1113/JP272270
- Panissa, V. L. G., Tricoli, V. A. A., Julio, U. F., Ribeiro, N., de Azevedo Neto, R. M. A., Carmo, E. C., & Franchini, E. (2015). Acute effect of high-intensity aerobic exercise performed on treadmill and cycle ergometer on strength performance. Journal of Strength and Conditioning Research, 29(4), 1077–1082. https://doi.org/10.1519/JSC.0000000000000706
- Murach, K. A., & Bagley, J. R. (2016, August). Skeletal Muscle Hypertrophy with Concurrent Exercise Training: Contrary Evidence for an Interference Effect. Sports Medicine (Auckland, N.Z.). New Zealand. https://doi.org/10.1007/s40279-016-0496-y
- Ratamess, N. A., Kang, J., Porfido, T. M., Ismaili, C. P., Selamie, S. N., Williams, B. D., Faigenbaum, A. D. (2016). Acute Resistance Exercise Performance Is Negatively Impacted by Prior Aerobic Endurance Exercise. The Journal of Strength & Conditioning Research, 30(10). Retrieved from https://journals.lww.com/nsca-jscr/Fulltext/2016/10000/Acute_Resistance_Exercise_Performance_Is.1.aspx
- Murlasits, Z., Kneffel, Z., & Thalib, L. (2018). The physiological effects of concurrent strength and endurance training sequence: A systematic review and meta-analysis. Journal of Sports Sciences, 36(11), 1212–1219. https://doi.org/10.1080/02640414.2017.1364405