When Should You do Cardio?

As a coach, I get asked this a lot... It seems like everyone has read or heard about the BEST time to do cardio, whether it’s for health, fat loss, or athleticism. I blame other people in the fitness industry for this, though, I don’t hold it against them. The truth of the matter is that there are slightly better and slightly worse times to do it, and I’ll talk about that, but there is only one true answer…

The Actual Best Time to do Cardio

The best time to do cardio (or anything for that matter) is whatever time is actually going to result in doing the darn thing. The thing about cardio is that with the exception of some satisfying endorphins you don’t necessarily reap any reward from it until you’ve done it many many many times over.

It’s hard to do something with no immediately obvious benefit and so choosing a time that is ‘optimal but not convenient is a recipe for skipped workouts. If in doubt, pick whatever time works best for you. If this is first thing in the morning, so be it. If it’s after resistance training, go for it. Whether you’re fasted or fed, tired or energized, whatever time works best for you is the best one. Now that the truth telling is out of the way, there are some extra considerations.

Extra Considerations

Fasted Cardio

If you are training in the morning, probably the first thing you want to decide on is whether you are performing your cardio fasted or fed (that is to say first thing in the morning or after you’ve had one or more meals). There are A LOT of opinions on this!

Some people feel strongly that doing cardio on an empty stomach will force your body to burn more fat (the principle is that it will utilize the body’s stores of energy since there is little energy to use from the gut). Scientifically this isn’t proven, but anecdotally some people swear by it. My take on fasted cardio is that it’s likely to be a little tougher on the body, perhaps requiring more recovery. I’m also inclined to believe (from experience and common sense) that exercising on an empty stomach will result in weaker performance, so if you’re concerned about hitting any new running time records or the like it’s probably not a good choice for you. Again though, some people really enjoy fasted cardio and if that’s the case for you then go for it.

Morning or Night

Whether you do your cardio morning or night does not matter, just be sure to not do it within a couple hours of going to bed as your elevated body temperature can delay sleep and reduce its quality.

Before or After Resistance Training

For many people cardio is done within the same gym session as resistance training. It’s likely better to separate cardio from resistance training though by at least a meal and a few hours to allow the body to recovery/prepare for/from each. However, this brings us back to the BEST time to do cardio (whenever it works best), so if grouping cardio and resistance training into one session works best for you than do it.

If you choose to do cardio and resistance training together then unless your cardio is practice for an athletic endeavour (e.g. racing, competitive, or endurance sports etc.) you are better off saving it for AFTER resistance training.  This allows you to put more of your energy, willpower, and strength into resistance training. Some studies also indicate that the body progresses more in whichever mode of training comes first, so if lifting progress is more important for you than cardio progress, do it first.

When cardio and lifting are paired together in the same session you might consider having a snack in-between or sipping on some intra-workout carbs and/or EAAs. If I was to choose just one intraworkout supplement it would be EAAs for post-workout cardio. This is to provide your body with a steady stream of nutrients and avoid metabolite depletion for better recovery and performance.

To sum up… Don’t overthink it. Do it when it makes sense for you and ignore all the noise out there that says to do it at at any specific time.