For many lifters, 2-3 sessions of zone 2 cardio per week, around 30-45 minutes each, is a practical starting point for building aerobic fitness without adding a huge recovery burden.
Not an hour on the stairmaster every day, and not zero cardio because you're afraid it'll shrink your squat.
Lifters tend to sort into two groups on this, and both miss the point. One group treats cardio like it's optional, something you'll "get to" once you're bigger. The other treats it like punishment for "eating too much" over the weekend, grinding out high-intensity sessions that leave nothing in the tank for the weight room.
Zone 2 gives you another option. Keep the intensity controlled, build your aerobic fitness, and leave enough in the tank for the training you actually care about.
This guide covers how much to do, how to estimate your zone, and where cardio fits around your lifting.
What You'll Learn
- Why most lifters program cardio wrong
- How to estimate your zone 2 without a lab
- How much to do and where to put it around lifting
- How to manage the interference effect without overreacting
- Zone 2 vs. HIIT: what each one costs and when each one fits
Why "How Much Cardio" Trips Up Most Lifters
The confusion isn't about whether cardio matters. Most lifters already know it does. It's about dosage and placement.
Here's what actually goes sideways:
- Doing cardio at an intensity that turns into hard conditioning.
- Skipping cardio entirely because you're afraid it'll interfere with strength or muscle growth.
- Scheduling intense cardio right before a heavy lifting session and carrying that fatigue into your lifts.
- Treating steady cardio and conditioning circuits like they're the same thing, even though circuits often come with higher intensity and more muscular fatigue.
Get the dose and placement right, and cardio becomes a lot easier to fit around your lifting.
1. Find Your Zone 2 Without Overcomplicating It
Here's something most cardio content skips over: exercise scientists don't have one universal cutoff for zone 2.
What experts generally agree on is where it sits. Zone 2 is usually placed immediately below your first lactate or ventilatory threshold, which is the point where steady aerobic work starts shifting into a more demanding intensity.[1]
Think of the zones as a scale from very easy effort to all-out work. Zone 1 is easier than Zone 2, while Zones 3 through 5 get progressively harder.
Unless you're being tested in a lab, you're probably not measuring that threshold directly. That's where practical field estimates come in. They don't define zone 2 perfectly, but they can help you estimate the right intensity without turning your cardio session into a science experiment.
- Talk test: You should be able to speak in full sentences. If conversation starts getting difficult, you're probably working harder than intended.
- Heart rate: Around 60-70% of your estimated max heart rate is a useful starting point. A quick estimate is 220 minus your age, but that number won't be exact for everyone, so use it as a guide, not a hard cutoff.
- Perceived effort: The first 10 minutes should almost feel too easy. That's fine. You're not supposed to turn every cardio session into a test of how hard you can push.
None of these methods are exact. The goal is to estimate an easy, sustainable aerobic intensity, not chase a perfect number.
2. How Much: Weekly Volume and Session Length
General health guidelines recommend 150-300 minutes of moderate-intensity aerobic activity per week. That's a total weekly activity guideline, not a specific zone 2 prescription for lifters.
If lifting is your main priority, a practical place to start is:
- 2-3 zone 2 sessions per week
- 30-45 minutes per session
- Incline treadmill walking, cycling, or another low-fatigue option you can do consistently
Walking with a weighted vest can work too, but the added weight creates more stress than normal walking, so factor that into your lower-body training and recovery.
Two or three 30-45 minute sessions won't always add up to the full 150-minute general health target. That's okay. Start with an amount that fits your training, then build your total weekly activity as your schedule and recovery allow.
Consistency beats intensity here. A boring 35-minute incline walk you actually do three times a week beats an ambitious cardio plan you abandon in two weeks.
3. Where It Fits Around Your Lifting Sessions
If strength or muscle growth is your priority, doing cardio before heavy lifting can create fatigue you don't need.
When cardio and lifting happen on the same day, keep it simple:
- Lift first.
- Do cardio afterward.
- Keep the cardio easy enough that it doesn't turn the end of your workout into another hard training session.
You can also separate cardio and lifting by several hours or put them on different days.
Rest days are another easy place to fit a zone 2 session, as long as the added work isn't starting to drag down your overall recovery.
The goal isn't to find one perfect schedule. It's to place cardio where it causes the least disruption to the work you're prioritizing.
4. Managing the Interference Effect Without Overreacting to It
You've probably heard that cardio kills gains. The actual research is a lot less dramatic.
When aerobic and strength training are programmed together, research overall does not show a meaningful loss in maximal strength or muscle growth compared with lifting alone. Where things can get more sensitive is explosive strength, especially when harder aerobic work and resistance training are packed into the same session.[2]
The interference effect is the idea that one type of training starts getting in the way of the progress you're trying to build from another. In practice, the effect appears to be much smaller than lifters are often led to believe.
It doesn't mean cardio and lifting can't coexist. It means the way you program both matters. Hard cardio still adds fatigue, so you need to account for it alongside your lifting.
Here's how to keep it under control:
- Keep easy cardio easy. Zone 2 shouldn't quietly turn into a hard conditioning session every time you get on the treadmill.
- If lifting is your priority, lift first. Put your best effort toward the training that matters most to your goals.
- Separate sessions when it makes sense. If you're training for strength or power and adding harder conditioning, putting several hours between sessions or using different days can give you more room to recover.
- Watch what happens in the weight room. If your normal working weights keep feeling heavier, the weight is moving slower, or your performance starts trending down as cardio goes up, that's a sign to look at your total workload.
Cardio isn't automatically the enemy of your lifting numbers. But adding more training on top of a program that's already pushing your recovery can become a problem.
If your energy and performance have been sliding regardless of cardio, there may be a bigger recovery issue going on. Read more about the signs of overtraining syndrome and what to watch for.
5. Progressing Over Time Without Losing Lifting Capacity
You don't need to jump from zero cardio to hours in a single week.
Build it gradually.
- Add 5-10 minutes per session every few weeks rather than jumping straight to longer sessions.
- During a strength peak or competition prep block, it's reasonable to temporarily reduce cardio frequency or duration if recovery or lifting performance starts to suffer.
- Track more than cardio minutes. Sleep, soreness, energy, and how your lifts are moving give you a better picture of whether your total workload is working.
Building your aerobic base is a long-term project, the same way strength is. Treat it with the same patience.
Zone 2 vs. HIIT: Which One Actually Fits a Lifter's Schedule
Both can have a place in a lifting program, but they come with different demands. If lifting is still your main priority, zone 2 is usually easier to fit around your training because the intensity and recovery cost are lower.
| Factor | Zone 2 | HIIT |
|---|---|---|
| Interference with lifting | Usually low when programmed appropriately | Needs more careful placement because of the higher intensity |
| Recovery cost | Low | Moderate to high |
| Aerobic fitness | Builds aerobic fitness with a lower-intensity approach | Can produce strong aerobic and VO2 max improvements, depending on the protocol |
| Typical use for lifters | Regular aerobic work alongside lifting | Occasional or strategically programmed conditioning |
| Best use case | Building aerobic fitness without adding a large fatigue cost | When improving high-intensity conditioning or VO2 max is a specific goal and recovery allows |
Bottom line: zone 2 makes sense as the default for a lot of lifters because it's easier to recover from. HIIT isn't bad. It just costs more. If you want it in your program, treat it like real training and account for that workload instead of throwing intervals on top of an already packed week.
Frequently Asked Questions
How much cardio should lifters do per week?
For many lifters, 2-3 zone 2 sessions per week at around 30-45 minutes each is a practical starting point. General health guidelines recommend more total moderate aerobic activity across the week, so you can build from there based on your goals, activity outside the gym, and ability to recover.
Will cardio kill my gains?
No. Cardio and lifting can coexist without wiping out your strength or muscle growth.[2] The bigger concern is how much total training you're doing, how hard the cardio is, and where it sits in your program.
Zone 2 vs. HIIT: which is better for lifters?
Zone 2 is usually the easier default because it builds aerobic fitness with a lower recovery cost. HIIT can still fit into a lifting program, but its higher intensity needs to be accounted for alongside your lifting volume.
Should I do cardio on lifting days or rest days?
Either can work. If you're doing both in the same session and lifting is the priority, lift first and do zone 2 afterward. Rest days can also work as long as the cardio isn't interfering with your overall recovery.
Is walking enough cardio, or do I need something more structured?
Walking absolutely can count. The key is getting the intensity high enough to reach the aerobic range you're aiming for. For many people, brisk walking or increasing the treadmill incline is enough to get there without turning the session into hard conditioning.
Build the Engine, Don't Just Build the Muscle
Cardio isn't the thing standing between you and your next PR. Bad programming is. Get the volume, intensity, and placement right, and cardio can work alongside your lifting without taking over your training. You don't need to choose between being strong and having a working aerobic system. Build both.
References
- Sitko, S., et al. (2025). What Is "Zone 2 Training"?: Experts' Viewpoint on Definition, Training Methods, and Expected Adaptations. International Journal of Sports Physiology and Performance. https://pubmed.ncbi.nlm.nih.gov/40010355/
- Held, S., et al. (2026). Maximizing Adaptations in Concurrent Training: An Umbrella Review of Meta-analyses. Sports Medicine, 56(6), 1489-1512. https://pubmed.ncbi.nlm.nih.gov/41762427/