Cardio workouts are any exercise that raises your heart rate and keeps it elevated for a sustained stretch of time, training your heart, lungs, and blood vessels to move oxygen more efficiently. Running, cycling, rowing, swimming, brisk walking, and interval circuits all count. If you lift weights, cardio isn’t a punishment for eating too much or a box to check before summer. It’s what keeps your heart strong, helps you recover faster between sets, and builds the endurance to finish a workout without gassing out on set four of five. Do it right and a few weekly sessions built around your training split add real engine capacity without eating into the muscle you’ve worked hard to build.
What Are Cardio Workouts, Exactly?
Cardio, short for cardiovascular exercise, is any activity that gets your heart and lungs working harder than they do at rest. It’s aerobic when your body has enough oxygen to fuel the effort (think a steady jog or a long bike ride) and anaerobic when the effort is too intense for your oxygen delivery to keep pace (think a 30 second sprint). Most cardio workouts fall somewhere between running, cycling, rowing, swimming, jump rope, incline walking, and structured interval sessions.
On a lot of fitness sites, cardio gets treated as a fat-burning tool and nothing else. That’s a narrow way to look at it. The bigger story is what cardio does for your heart, your lung capacity, your resting heart rate, and your ability to recover between hard training sessions. For someone who lifts, that recovery capacity matters as much as the numbers on the bar.
Why Do Cardio Workouts Matter If You’re Trying to Build Muscle?
A stronger cardiovascular system means your heart pumps more blood per beat, your muscles clear metabolic waste faster between sets, and you recover from a heavy leg day quicker than someone with an undertrained heart. That’s not a minor side benefit. It directly affects how much quality work you can do in the gym week after week.
There’s a real concern lifters have, and it’s not unfounded: too much cardio, especially high-volume steady-state work, can blunt strength and size gains through what exercise scientists call the interference effect. Your body has limited recovery resources, and if you’re asking it to build an aerobic engine and build muscle at the same time, in large volumes, something gives. But the research on this is pretty clear that moderate cardio, programmed sensibly, doesn’t meaningfully hurt hypertrophy or strength. The problems show up when cardio volume gets excessive, when it’s done right before a lifting session, or when recovery and nutrition aren’t dialed in to support both goals.
What’s the Difference Between Steady-State and Interval Cardio?
This is the split that matters most when you’re programming cardio around strength training.
Steady-state cardio (LISS, Low Intensity Steady State) is exercise at a consistent, moderate pace for an extended period, usually 20 to 45 minutes. Think a brisk incline walk, an easy bike ride, or a light jog where you can hold a conversation. It’s low-impact on your joints, easy to recover from, and builds your aerobic base without competing hard with your lifting sessions for recovery resources. It’s also the easiest type of cardio to do consistently, which counts for more than people give it credit for.
Interval cardio alternates short bursts of hard effort with periods of rest or easy movement. HIIT (High Intensity Interval Training), sprint work, and tempo intervals all fall in this category. Interval sessions are shorter, they spike your heart rate into a higher zone, and they build VO2 max (your body’s ceiling for using oxygen) faster than steady-state does. The tradeoff is that interval cardio is more demanding on your nervous system and recovery, so it needs to be capped and placed carefully around heavy lifting days. If you want a full breakdown of interval training and how to structure a session, our HIIT workouts at home guide covers that in detail.
Neither one is “better.” LISS builds your base and is easy on recovery. Intervals are more time-efficient and push your cardiovascular ceiling higher. A well-built cardio routine uses both.
Sample Cardio Session Options by Intensity
| Intensity | Example Session | Duration | Perceived Effort (RPE 1-10) | Heart Rate Zone | Best For |
|---|---|---|---|---|---|
| Low (LISS) | Incline treadmill walk or easy stationary cycle | 30-45 min | 3-4 | Zone 2 (~60-70% max HR) | Recovery days, aerobic base, low joint stress |
| Moderate (Steady State) | Jog, swim, or rowing machine at conversational pace | 25-35 min | 5-6 | Zone 3 (~70-80% max HR) | General cardiovascular fitness, endurance building |
| High (Intervals) | 4-6 rounds: 1 min hard effort, 2 min easy on bike or rower | 20-25 min | 7-8 | Zone 4 (~80-90% max HR) | Time-efficient conditioning, raising VO2 max |
| Very High (Sprints) | 6-8 x 20-30 sec all-out sprints, full recovery between | 15-20 min total | 9-10 | Zone 5 (90%+ max HR) | Power, speed, anaerobic capacity |
If sprint work interests you as a training tool on its own, not just as a cardio filler, our sprint workouts guide breaks down structure, progression, and how often to run them.
How Should You Program Cardio Workouts Alongside Strength Training?
A few rules keep cardio from working against your gains instead of for them:
- Separate the sessions when you can. If you’re lifting and doing cardio on the same day, put a few hours between them, or do cardio in the morning and lift in the evening. Back-to-back sessions with no gap between a hard interval workout and heavy squats is asking a lot of one nervous system in one day.
- Cap the high-intensity stuff. Two interval or sprint sessions a week is plenty for most people who are also lifting four to five days a week. Beyond that, recovery starts to suffer and your lifts feel flat.
- Use LISS as a recovery tool, not just a burn tool. A 30-minute walk on a rest day or after a lower-body session actually speeds up recovery by moving blood through tired muscles. It’s low-cost cardio that doesn’t dig into your recovery bank.
- Fuel it properly. Cardio on top of a strength program increases your total energy demand. If you’re trying to build muscle and you cut calories too hard while also adding cardio volume, you’ll lose the fight on both fronts. Eat to support the work you’re actually doing.
- Prioritize lifting when it matters most. On days where a big lift is on the schedule, keep cardio short and easy, or skip it. Save your harder cardio sessions for days with lighter lifting or off days.
What Does a Sample Week of Cardio Workouts Look Like for a Lifter?
We see a lot of clients who train hard in the gym four or five days a week but skip cardio entirely, then get winded walking up three flights of stairs with grocery bags. That’s not a sign they need to lose fat. It’s a sign their engine hasn’t been trained at all, and it eventually shows up as slower recovery between sets and flat performance late in a session. A week like the one below fixes that without pulling focus away from lifting.
| Day | Main Training | Cardio | Notes |
|---|---|---|---|
| Monday | Strength: Upper body | None, or 10 min easy walk as warm-up | Keep cardio minimal on your heaviest push/pull day |
| Tuesday | Strength: Lower body | None | Full focus on the lift, save cardio for tomorrow |
| Wednesday | Rest or light mobility | LISS: 30-40 min brisk walk or easy cycle | Active recovery, gets blood moving without taxing the system |
| Thursday | Strength: Push | None | |
| Friday | Strength: Pull (lighter volume) | Interval session, 20 min (see HIIT workouts at home) | Do lifting first, cardio after, or space by several hours |
| Saturday | Strength: Legs or full body | Optional: Zumba dance workout or other fun cardio, 30-40 min | Keeps cardio enjoyable so you actually stick with it |
| Sunday | Rest | Optional easy walk | Full recovery, light movement only |
This isn’t a rigid template. Swap days based on your own split, but the underlying logic holds: heavy lifting days get little to no cardio, one day carries your interval or sprint work, and LISS fills the gaps as recovery-friendly volume.
What Are the Real Benefits of Cardio Workouts, Beyond Burning Calories?
A lower resting heart rate. Better VO2 max. Faster recovery between sets and between training sessions. Improved blood pressure and cholesterol markers over time. Better sleep. A mood boost that’s hard to fake with anything else. These are the reasons cardio earns a place in a program built around strength and muscle, not because it torches calories during the session itself.
There’s also a longevity angle that doesn’t get enough attention in strength-training circles. A strong cardiovascular system is one of the better predictors of long-term health outcomes, independent of how much muscle you’re carrying. Building both, a strong heart and strong muscles, is a far better long-term bet than optimizing for one and ignoring the other.
If structuring all this on your own feels like guesswork, that’s exactly what coaching solves. A trainer who understands your lifting split, your recovery, and your goals can build cardio into your week without it competing against your strength numbers. That’s the kind of programming we build into every 1-on-1 personal training plan at FitStrot, matched to your schedule, your training age, and what you’re actually trying to achieve.
Frequently Asked Questions About Cardio Workouts
What are cardio workouts?
Cardio workouts are exercises that raise and sustain your heart rate, training your heart, lungs, and circulatory system. Running, cycling, rowing, swimming, brisk walking, and interval training all qualify. They range from low-intensity steady sessions to short, intense interval bursts, and each type trains your cardiovascular system a little differently.
How do you do cardio workouts properly?
Pick an intensity that matches the day: easy steady-state on recovery days, harder intervals once or twice a week when you’re fresh. Warm up for five minutes, keep effort honest to your target zone, and separate hard cardio sessions from heavy lifting by several hours so one doesn’t compromise the other.
What are the benefits of cardio workouts?
Cardio workouts strengthen your heart, lower resting heart rate, improve VO2 max, and speed up recovery between lifting sessions. They also support better sleep, blood pressure, and mood. For lifters specifically, a trained cardiovascular system means less fatigue and better performance late in a heavy session.
How many days a week should you do cardio if you’re also lifting?
Two to four sessions a week works for most lifters: one or two easy LISS sessions and one or two interval sessions, capped so recovery for your lifting days doesn’t suffer. Beginners can start with two sessions and add more once their body adapts to the combined training load.
Can you do cardio and strength training on the same day?
Yes, as long as you space them out or keep the cardio short and easy. Lifting first, then doing light cardio afterward, works well for most people. Stacking a hard interval session right before heavy lifting tends to hurt performance, so save intense cardio for separate days when possible.
