3 Reasons Why You Should Perform Cardio After Lifting

Cardio and lifting; can they co-exist in your workout program? In short, yes. They both have benefits and can improve the other’s performance. Cardiovascular training will improve the body’s ability to transport and utilize oxygen in the body, which will have carry over to your lifting. Resistance training (lifting) will strengthen muscles that benefit running, or other cardio forms of your choosing.

Can too much of one affect the other? Yes. For example, excessive cardio can inhibit muscular gains, so there needs to be strategy around your cardio training and lifting if size and strength are your goals. If your goal is size and strength, you don’t have to eliminate cardio altogether, but you should plan it around your lifting.

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How much is too much? That’s a loaded question that even science has a hard time answering due to every lifter’s anthropometric differences (ex: hardgainers). Yet, when it comes to performing cardio before or after lifting, we can look to science for a few suggestions

1. Muscular and Mental Fatigue

Experienced lifters generally understand that cardio before lifting will inhibit workouts due to fatigue. It’s the beginners who want to start lifting that this concept impacts most. Most gym-goers begin their career in gyms performing cardio. The treadmill and running is one of the most universally known skills for getting healthy. It’s widely understood that running is healthy, so…most people start on the treadmill.

A big issue with cardio before lifting has to do with the fatigue cardio can induce. Excessive running can leave an athlete tired, which will impact the amount of force they can produce. If the muscles or nervous system is even slightly impaired, then you’ll have a tough time performing optimally under the bar. Not to mention, fatigue can also impact your mental sharpness, which may leave you with lack of focus. This can be especially true for those who lift later in the day, and already have a hard time with mental focus.

2. Energy Systems

Excessive cardio pre-lift can also deplete the energy system you need to perform optimally under the bar. The body has three types of energy systems and they include: ATP-PC, Glycolytic, and Oxidative. Each energy system will play a role in different activities and their rough time estimates based off of maximal energy demands are shared below.

  • ATP-PC Energy System: (+/-) 12-seconds
  • Glycolytic System: 30-seconds – 2-minutes
  • Oxidative System: 2+ minutes

Keep in mind these are estimates science generally agree upon, and there are a ton of factors that will influence each energy system in different lifters. The table below provides different scenarios when each energy system is used for cardiovascular and resistance training.

Cardiovascular Training Resistance Training 
APT-PC – Short all out sprints ATP-PC – Heavy lifts in 1-3 rep range
Glycolytic – 400-800 meter runs Glycolytic – Heavier lifts in 4-8 rep range
Oxidative – 800+ long duration runs Oxidative – High-rep work 10+

 

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So what does the above information mean? This question can best be answered by asking another question; what type of cardio and lifting are you performing that day? If you’re performing high-intensity sprint work, then you’ll tax energy systems that heavier lifts require (if you’re performing them too). This is why lifting should take priority over cardio training when performed on the same day (consider safety too).

To provide you an example, our body only holds so much glycogen in the muscles and liver (primarily used in the glycolytic energy system) that can be used for training. If we use the amount we have stored for cardio before lifting, then our strength and power-output may suffer due to lacking energy resources.

Once you’ve consider the above question, chose to put cardio after lifting, and understand the energy systems needed for both styles of training, then you’ll have two scenarios.

  • Do you want to break up high-intensity resistance/cardio work?
  • Do you want to perform a full high-intensity resistance/cardio day?

This will be up to the athlete, coach, and training being performed. Some athletes will benefit from doing an all-out high-intensity day (functional athletes), while others might benefit from breaking them up (strongman athletes). Rest after training days should also be considered when answering the above scenario. What will benefit your training goals best?

3. Conflicting Enzymes

To keep this section short, there are enzymes that have been hypothesized to conflict with resistance and cardio training. The enzyme mTOR (mechanistic target of rapamycin) is a key player in protein synthesis and has been seen to be elevated post-workout. This elevation can last up to 48-hours post-workout (think anabolic window).

The enzyme AMPK (5′ adenosine monophosphate-activated protein kinase) has been seen to be produced more so after low-intensity based exercise. So what’s the issue? Well, studies have hypothesized multiple ideas of how these two enzymes influence each other with different training styles. study from 2011, suggests that increased AMPK acutely produced during endurance training lowered mTOR signaling. In addition, an hypothesis from this 2003 study, suggests that the linkage between AMPK and mTOR revolves around AMPK’s ability to override mTOR signaling (intra/post-training).

This overriding of mTOR may slow down the rate or amount of protein synthesis you experience post-workout. For someone interested in packing on the most amount of strength and size as they can, then this can be counter-productive. Keep in mind, this factor is on the lower-end of importance. Fatigue and energy demands will play a much larger role in your overall gains in each style training.

In Conclusion

Cardio and lifting can co-exist, but there should be strategy behind how you program them. If the above factors have left you a little confused, then check out the below video for a visual, which summarizes these factors as well.

If lifting is your main focus, then you’ll benefit most from performing your cardio post-lift. When deciding where and how to program cardio and resistance training consider your sport, training style, rest, and training history.

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