Does Science Say You Should Strength Train or Do Cardio First?

Cardio First

Strength training is your ticket to stronger muscles and more defined muscles and helps with weight loss too. Plus, it’s the ultimate body anti-aging prescription. Working your muscles against resistance also reduces muscle loss related to the aging process that affects everyone beyond the age of 30 and continues throughout life.

In contrast, cardio workouts boost your heart rate enough to improve aerobic fitness and stamina while also lowering risk factors for cardiovascular disease. So, they’re both important for different reasons and a balanced workout should include both.

But what if your time is limited and you only have a few days to work out each week? If you have little time to train and have to do a cardio workout and a strength routine on the same day, you might wonder which you should do first or whether it matters.

The answer depends on your goals. You might want to build muscle and lose body fat, but which of these matters most at the current time? The activity you do first can reduce your performance on the second activity because of the fatigue factor. Exercise depletes energy reserves and you only have a finite amount. It’s hard to maintain the same stamina and focus when you’re fatigued from the first activity.

What’s Your Primary Fitness Goal?

If your main goal is to build muscle strength or muscle size, strength train first while you’re still fresh. If you take a run or do a high-intensity interval workout before picking up the weights, your performance, especially for your lower body, will suffer. Why? Because running or high-intensity interval training fatigues your legs, and you won’t perform as well when you do exercises like squats and lunges that require leg strength.

Research shows lower body training can interfere with cardio performance, while upper body training does not. So, if you weight train before cardio, train your upper body only, so you still have strength reserves in your lower body. Strength training also requires mental focus, and if you’re fatigued from cardio, you might not have the focus you need to maximize your form.

If Your Goal is to Boost Aerobic Fitness

If you’re mainly concerned with building greater aerobic fitness or enhancing the health of your heart, doing cardio first will help you meet that goal. You’ll tackle that running, cycling, or high-intensity interval workout when you’re least fatigued and can give it the strongest effort. You can still follow up a cardio session with weight training, but don’t expect to perform as well as you would if you have reversed the order. Still, you’re training in a way that maximizes your primary goal – aerobic fitness.

If you’re training for a race and need to maximize your endurance, run first. A study found that when subjects strength trained before running, their running economy suffered, and their performance declined. The same would be true if you’re a competitive cyclist where you need to build as much endurance as possible.

If Your Goal is to Lose Body Fat

If you want to shed body fat, you might think that doing cardio first is in your best interest since it’s the big calorie burner, but there’s another way to look at it. When you train with heavy weights, it depletes your muscles’ glycogen stores, the dominant form of energy they use during a workout. Once you’ve depleted most of the muscle’s glycogen, your muscles are forced to use fat as fuel instead and that may increase fat loss.

Though studies don’t definitely prove this, some fitness experts believe strength training before cardio boosts fat loss by forcing muscles to use more fat as a fuel because they’re glycogen depleted. The downside of strength training first for weight loss is you may be tired after a strength workout and not do cardio with as much intensity. So, it’s a balancing act.

If you’re trying to lose body fat, don’t shun strength training because cardio burns more calories. Strength training helps you build more metabolically active tissue that helps support a healthy metabolism. It also improves insulin sensitivity, which is beneficial for weight control.

The Bottom Line

Which form of training you do first should depend on your goals. You’ll devote the most energy to the workout you start out with since you’re least fatigued at the beginning of a workout. Therefore, there isn’t a right or wrong way to train since your goal may differ from someone else’s. If you have all three goals, lose weight, build muscle, and improve aerobic fitness, you could even alternate which you do first. During one training session, do weights first and in the next, cardio.

Don’t get too caught up in which way to train first. The difference it will make in your overall development will likely be small. What matters the most is consistency and putting in the time and effort. Are you showing up for each workout and giving it your best? Then you should see results with time. In the big scheme of things, nothing matters more than consistency.

Show up, give it your best, and you’ll get there, don’t focus on cardio, as a calorie burner, to the exclusion of strength training. Strength training is more essential than ever in your weight loss journey. It’s not just about losing fat — it’s about sculpting the body you’ve always wanted. You need weights or some form of resistance to do that.


  • The Journal of Strength & Conditioning Research: April 2015 – Volume 29 – Issue 4 – p 1077-1082. doi: 10.1519/JSC.0000000000000706.
  • Medicine & Science in Sports & Exercise: February 2007 – Volume 39 – Issue 2 – p 308-315. doi: 10.1249/01.mss.0000246992.33482.cb.
  • Doma, Kenji & Deakin, Glen. (2013). The effects of strength training and endurance training order on running economy and performance. Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 38. 651-656. 10.1139/apnm-2012-0362.
  • Military.com. “Cardio or Weights: Which Comes First?”
  • ACEFitness.org. “Cardio or Weights First? Cardio Before vs. After Lifting”


Related Articles By Cathe:

Should You Do Cardio After Weight Training?

Pros and Cons of Split Training for Building Lean Body Mass

Resistance Training: Does Exercise Order Matter?

Does Exercise Order Impact Strength Gains?

Related Cathe Friedrich Workout DVDs:

Fit Split Exercise DVDs

All of Cathe’s Strength & Toning Workout DVDs

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