Using the interference effect to maximize by cardiorespiratory fitness.

Training Q&A [Moderated]
1

Sorry for the title. It’s a little tounge-in-cheek.

I don’t have the time to separate my cardio and my lifting workouts, so I do them back-to-back with no break.

I’m currently lifting three days a week and doing cardio four days a week. My cardio, depending on the day, varies between incline walking, rowing, and jump rope. I have a Fitbit which tracks my heart rate, but it’s super cumbersome to look at what my heart rate is during the exercise so I’m not adjusting my intensity really at all based on heart rate or RPE.

So if I do incline walking on a non lifting day my heart rate is between 110-130 bpm the whole time. I do it right after lifting, 130-140. Same thing with rowing or jump rope. And the RPE is higher as well, what would be a really easy LISS session becomes a moderately difficult session.

Is this “better” for cardio respiratory fitness? I imagine it’s worse for getting better at something like rowing since I am doing the session already pretty tired. But from the standpoint of my heart and lungs, is a 20 bpm higher a “more effective” workout?

2

The additional cardiorespiratory response post lifting is mostly due to fatigue, sympathetic nervous system priming, and some fluid losses. If anything, I’d favor your walks on non-lifting days to be more intense to get your HR to match the 130-140 you’re getting post workout. I don’t think there’s likely to be much difference in cardiorespiratory fitness in these small differences for relatively low volume (< 180 min/wk).

Tl;dr- probably no difference