Cardio or Weights: Which Comes First?

People running on treadmills before doping weights

By Simon Gould

This is the ultimate question for anyone who starts exercising in a serious way. Some people might have a priority in their exercise routines. They may place weight training above cardio and want a good physique. Some people might be focused on cardio work and enjoy running. But on those days where we’re doing both, which should we do first?

Why combine the two?

If you prefer weight lifting and want a good body shape, why do any cardio at all? Same if you prefer long distance running, why do any weight training? The reason to do both is because they benefit each other. A weight lifter may want less body fat to show those arms or six pack. The best way to do this is by burning calories and nothing does that better than cardio work.

A runner may want more explosive pace, they may want to run faster to get better times. Doing some leg work is ideal for this, you don’t get the same benefit on a treadmill. Cardio or aerobic activity is best for burning fat, while anaerobic activity or strength training is best for building muscle. So we’ve established we want to do both cardio and strength work, which do we do first?

What the science says

The US National Library of Medicine & Institutes of Health have a few published scientific papers regarding this very question. One paper specifically looked at strength training prior to endurance exercise. They concluded that there was no significant difference in total energy used which ever one you do first. But that’s what happens in terms of energy usage.

The same paper said that whatever exercise you do first, will have an impact on the second if done on the same day. So weights first will have an effect on the amount of cardio exercise you can do after. So it comes down to which is your main priority, do you workout to lift weights, or do you prefer the cardio side of things. Here’s the research.

Anecdotal evidence

So I’ve gone through the most authoritative research paper on the subject. Now to look at what other people think. The Ripped Dude is an expert in the field at and gives a few reasons why strength training is best done first. He says that glycogen stores are better used for the intense strength work, so then fat can be burned on the treadmill.

The American Council on Exercise have an article but they have mixed views on which to do first. They propose different aims and which you should do. They advise on a strength leg day, to avoid cardio. They give many solutions based on your training priorities, but lean on strength training first, followed by cardio work.

My solution: Don’t do cardio and weights on the same day

If you do weights, you’ll do that on most days of the week. The same is if you do cardio, you’ll do that on most days of the week. But you don’t do it 7 days a week, or at least you shouldn’t. If you want to get the most out of the work you do, then do them on separate days. You’re not going to get a good cardio workout done after strength training, and it goes the other way too.

So on one of the days when you don’t do your main exercise, do the other. It does mean more time in the gym, but you’d be working more efficiently. You’ll burn out if you do both on most days of the week. You don’t feel like doing them on the same day anyway So do weights on 5 days and cardio on 1 day of the week and the opposite for cardio lovers. This way you get the best of both worlds.

My experience

I love running and understand that strength exercises help my running by working the core and leg muscles. It also gives me a nice body shape as I do the upper body. When ever I’ve gone for a run after doing strength training, I can’t do as much. I will often schedule an easy run day if I am doing strength training on that day also.

If I’ve done strength work on my legs, then there’s no point in doing a run. I find my legs have fatigued enough without doing a run on the same day. Almost all cardio involves the legs, so an elliptical, bike or rowing machine is out of the question. And like the above research paper says, upper body strength routines still affect my ability to get a good run but not as much.

Final thoughts

It makes sense to me that you do the most intense exercise first. Endurance is hard but the intensity of a strength day needs your energy and focus first. The scientific paper agrees your endurance exercise is not going to be your best by a long shot. The recommended amount of exercise and type adults should get is an enormous amount so some will be done on the same day.

If you’re serious about training and have your schedule planned out for each week, I have the miles I will run each day planned well in advance. I think you will probably find what’s best for you and find a happy medium. I will continue to follow the idea of weights before cardio on days they overlap, as that seems the best thing to do for me.

Thinking of buying a treadmill? Here’s my favorite, I always recommend it when asked.

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