Cardio before or after weightlifting? Here’s the truth.

Hey guys!

I’ve been getting some feedback on my 90 Day Journey to Muscle updates questioning how my daily runs could be impacting my strength gains. So, I decided to dig in and see what the experts say about this! Is it better to run before or after a lifting session? Can doing cardio the same day as a lift lower potential muscle gains?

One thing before we get all sciency though. At the end of the day, this fitness journey is for me. Yes, I’m trying to gain muscle and of course there is a “best way” to do this. There are textbook guidelines I could obsess over. Someone is always going to know more than me.

HOWEVER, I enjoy running every day. It’s that simple! For a long time (like, most of my life), I despised running. Over the past few years, I’ve grown to love it because it’s my time to listen to a book or podcast and just be in my thoughts… not working 🙂  It’s therapeutic for me, and that’s why it’s staying in my routine at some level, no matter what the research says.

Anyways, let’s learn a little about cardio and muscle gains, shall we?!

Cardio + resistance training = concurrent training

When a program includes cardio and resistance training, it’s called concurrent training. And it’s SUPER common, from athletes to people who workout for general fitness. However, using this type of program when muscle building is the goal does seem to be a little controversial in the fitness community.

What does the science say though? While I was looking at articles and reading both sides of concurrent training pros and cons, I landed on a systematic review and meta-analysis that was conducted to update info from another review done in 2012. The new review (2021) looked at a total of 43 studies, focused on how combining resistance training and cardio in the same fitness program affects muscle hypertrophy (growth), maximal strength, and explosive strength. Wanna know what they found?

Combining cardio and resistance training doesn’t interfere with muscle growth or maximum strength gains. But it CAN impact explosive strength.

First, what’s the difference between maximum strength and explosive strength?

Maximum strength is the most force possible. The highest amount of weight you can lift for one solid rep.

Explosive strength is short, quick bursts of power. You’re moving the weight as fast as possible.

In this review, people who combined aerobic activity (cardio) with strength training saw similar gains as people who focused on strength training alone. Also, it didn’t seem to matter if people combined the two on the same day or had separate “cardio” and lifting “days.”

The explosive strength part is interesting though! Obviously this is an important finding for athletes or people who are training that specific type of strength. The authors of this review recommend at least separating lifting days from cardio days, and possibly decreasing cardio sessions overall to maximize explosive strength gains.

Another interesting thing about this review – according to the authors, most of the older research that suspected cardio may interfere with muscle growth used rats and cell models to make these connections. In this current review, all of the studies are based on human results.

Obviously this still isn’t black and white

You know what I’m going to say. Everyone is different!! Some people probably do find that their results are slower when they include cardio while trying to build muscle. And OMG you can get into a serious rabbit hole digging into the reasons why this may happen. Hormone levels, nutrition, overtraining, hydration, age, genetics, etc. According to another review I read, there just isn’t enough research yet to say for sure exactly why concurrent training works for some but not others.

The authors dive into different molecular pathways, training rations, and a lot of other details, but here’s what I found really interesting:

A person’s training experience and background may be key. So in other words, someone who is highly trained and experienced in fitness is more likely to experience the “concurrent training effect” (cardio negatively impacting gains), whereas people who are newer to strength training may not notice any negative effects.

The takeaway – this is why no single program works for everyone!

And training appropriately is key

Most of the time, the issue with combining cardio + strength isn’t how the cardio literally impacts the muscle. It’s how it could affect your workout performance. When you’re doing cardio and lifting, you risk using up your energy for the cardio part, leaving you with less for your lift. Less energy for your lift = less effort, using lower weights, poor form, etc.

Of course the end result in this situation is lower gains. Annnnd maybe an injury if you’re not careful.

This is where personalization is so important for training plans.

Some people might feel pretty fatigued after 20 minutes of cardio. Some people can go much longer without feeling like they’ve drained their energy.

My run is honestly my warmup. It gets the blood flowing. Just an appetizer for the main course later in the gym!

cassey ho is cardio killing my muscle gain

Should I do cardio before or after I lift?

I get this question all the time! And guess what? It depends. Here is what I would think about to make this decision and maximize your workout!

Consider the mental aspect of your workout.

Are you more focused at the beginning of your workout? If yes, then lifting first might be better. Since form is soooo crucial with lifting, you really need to be mentally present. Then, you can use cardio to “wind down.”

Which way makes you feel more powerful during your lift?

Running before I lift hypes me up and makes me feel more powerful during my workout. But some people might experience the exact opposite. If cardio drains you, fatigues your muscles, or just leaves you tempted to cut corners during your lift, save it for the end of your workout!

Think about your goals

What is your “why?” What is the progress you want to see? If you’re just looking to work on fitness, stick to your routine, get healthy, etc., go with whatever you enjoy and will stick to. Most people trying to build muscle will prefer to lift first. On the other hand, people focused on endurance will probably prefer cardio first. Use this as a place to start if you’re just starting your routine! If you feel like it’s not working for you, switch it up!

cassey ho sweaty selfie post workout thumbs up wearing popflex basics alpine bra mocha

So, is cardio killing my muscle gains? Probably not.

But things could change. Who knows!

So far, there’s nothing making me think that my daily runs are getting in the way of my progress. For me, doing cardio first fires me up and gets my head in the game for my lift. I feel energized and I don’t feel like my muscles are already fatigued.

However, I totally realize I’m not very far into my journey just yet. As I start lifting heavier and progressing in other ways, I may find that cutting back on my runs or adjusting in some other way will work better for me. When the time comes, I’ll adjust if needed!

That’s what a fitness journey is all about, right?

15 thoughts on “Cardio before or after weightlifting? Here’s the truth.”

There are 15 comments posted by our users.

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  1. Inga says:

    One of the reasons I like reading your blog posts is how they make me excited to work out. The motivation you give is unreal ✨ you’ve done it again with this one.

    Personally, I’m also a cardio first person, because I tend to feel sluggish at the beginning of a workout.

  2. Lynnell says:

    You are so awesome! I love the way you handled your feedback. Thanks for your research also and for being humble enough to grow!!

  3. Swati says:

    Cassey this was really insightful!!! And don’t let the haters bug you ! Some people honestly have a hell lot of time to bring down other women ! You do you!!!
    Love from India

  4. Anna says:

    I sooo prefer cardio at the beginning of a workout! I feel like it warms up my muscles and gets me sweating faster than if I just start my workout. I also would be more likely to skip it all together if I tacked it onto the end lol.

    1. Cassey says:


  5. Camille says:

    I’ve been a runner for over ten years and it’s always been #1 for me. But I love other forms of exercise as well! My current workout split is actually very similar to yours. I love running before strength training and agree that it helps me warm up. Plus, endurance is key to pretty much everything in life in my opinion. Everything that I’ve learned about myself as a runner, I’ve applied to strength training.

    There are a lot of male gym bros who coin this as “hybrid” training. Everyone in their comments section praises their work ethic. But anytime a woman does intensity like that, it’s deemed too hardcore. It’s just ~so~ unfathomable that women can love cardio and lifting weights.

    Very happy that you brought research into this! But I don’t think research is even needed bc we’re all so metabolically different.

    1. Cassey says:

      YES! All of this.

  6. Gill says:

    I personally get a bit sloppy with my weights or form when I’m getting tired. I do feel a bit unstoppable once I’m really revved up, and some running or stair master after weights feels like a bonus workout. I may only have 10 minutes left in my tank but at least less of a chance of injury.

    1. Cassey says:

      So important to prioritize form!!

  7. Samantha says:

    Honestly, the only cardio I would not do is HIIT before lifting? Running and walking are perfectly fine. I know people who spend 30 minutes on the stair master before starting their gym session. Now I want to go on runs before weight training! I want to start running but I didn’t know how or when to incorporate it with my current routine. You are so right—cardio before strength is just a matter of how much you burn yourself out. Thanks, Cassey!

  8. Sara says:

    Thanks for sharing!

    When referencing a scientific article, you should always link to or quote your source for others to be able to check it out and see that it’s scientifically sound and that your interpretations are correct.

    1. Cassey says:

      Every study and article I referenced is linked! Which one are you referring to?

  9. Becky H says:

    I agree with you! My warm up is 20 mins of cardio and it prepares me well and helps me burn more calories overall x

    1. BB says:

      That’s the thing though, it puts you at a greater deficit calorically. Great for losing weight or maintaining, but not good for building muscle. You need a caloric surplus to make muscle, that’s usually why people are not successful doing both. For some people trying to bulk it’s hard to eat enough to make up for the run and the strength training and then extra to bulk.
      Ideally we could do both and reap the benefits of both but it depends on the person’s goal.