Should you do cardio before or after your weight workout? This question is always popular, and as a certified personal trainer, I get this question quite a bit. Should cardio be done before your weight workout (strength training), or afterwards? This question assumes that on any given weight workout day, you have committed to doing some form of cardio. And that is where the problem lies.
Who says you must do both cardio and weights on the same day in the first place? This isn’t even necessary. Though you may find yourself doing cardio and strength training on the same day on an occasional basis, due to time constraints or missing a workout, that’s understandable, and it won’t disrupt your progress. But I strongly advise against planning on doing cardio and weights on the same day as a routine protocol of your workout regimen.
Before I go on, I will define “cardio” as that which is challenging at a minimum. If you have a habit of walking on a treadmill or casually pedaling a stationary bike for 20 minutes preceding a heavy weight routine, this is not the same as “cardio.” To me, “cardio” means something more rigorous than merely pedaling at level 5 on the stationary bike or walking 4 mph on a treadmill.
Your actual, bona fide cardio routine should be done on a different day than your weight lifting, strength training or bodybuilding routine. The only exception may be people who are a few weeks to a few days out from a bodybuilding or physique contest, in which they do both weights and cardio on the same day. They are also fully aware of the risk of losing muscle mass in the process.
For all other fitness enthusiasts, do cardio on one day, strength training the next. Here’s why: For your absolute best effort with your weight lifting/bodybuilding/strength training routines, you must go into your exercises NOT pre-fatigued. You must go into them fresh, with a full tank of gas.
If you conduct cardio (anything that’s challenging, gets you winded, sweaty, out of breath, makes you feel like you just did a good cardio session) before your weight workout, you will then be going into your strength training on less than a full tank of gas. You will be fatigued; your muscles will already be partially spent.
And even though the fatigue will involve mostly slow-twitch muscle fiber, which is designed for sustained activity, and even though most of your strength routine involves fast-twitch muscle fiber, which is designed for brief bursts of high energy, you will STILL be operating on much less than a full tank of gas.
But it may not seem so. If you do high intensity interval training on a treadmill, then jump right into barbell squats, bench presses, pull-ups, rows, or what-have-you, you may not perceive any deficits in your performance. But rigorous cardio that precedes a hefty weight routine WILL cut you down a few notches in performance in at least some of the exercises.
Not only that, but it may interfere with recovery from the weight workout. You want your body’s recovery to focus 100 percent on strength training, rather than “share” it with the cardio you did.
I myself have done strenuous cardio intervals preceding a weight workout and felt no deficits, but my cardio intervals lasted only 30 seconds, and I did only three of them (90 seconds’ total exertion), then went straight to my weights. This isn’t the same as running 7-8 mph on the treadmill for 30 minutes, huffing and puffing throughout the entire 30 minutes, heart rate way up, then doing a full-fledged strength program.
Save all your energy for the weight workout by doing cardio on other days. Another thing to consider is the psychology. It’s harder to look forward to an exercise session when you’ve planned both rigorous, sustained cardio AND a full-fledged strength training routine to occur in the same session.
Conversely, don’t do cardio AFTER the weight routine, either. After you’ve just punished your body with a strenuous weight workout, your body needs to recover. Doing cardio afterwards will sabotage recovery efforts; will interfere. It’s okay to walk without effort for 20 minutes following weights, or pedal without effort for 20 minutes following weights. But high intensity interval training, or sustained rigorous cardio, after strength training, should be eliminated, as it will interfere with recovery, not to mention make your entire exercise session a drudgery to face every time.