Most people have a love-hate relationship with leg day due to its difficulty.
But is leg day classed as cardio?
Here’s whether leg day is considered cardio:
Leg day is classed as cardio as it stimulates your cardiovascular system. When you train your legs, you exercise the heart and vascular system, and so by definition you’re doing cardio.
In this article, we cover what cardio is, why leg day is cardio, whether you should skip other forms of cardio, and more!
What is Cardio?
Most people use the term ‘cardio’ when they actually mean aerobic training.
The essence of a ‘cardio workout’ is that it refers to exercise that stimulates your cardiovascular system (mainly the heart).
So, anything that maximally exercises the heart can count as cardio.
If you are one of those who associates cardio solely with the treadmill or stationary bike, stop for a second and think whether any other forms of exercise stimulate the heart.
Why Leg Day Is Cardio
When you exercise, your muscles fill up with blood to help deliver oxygen and nutrients to the muscle tissue.
(This is what gives you a ‘pump’.)
Now, since your legs are the biggest muscle group in your body, your heart needs to work overtime by pumping blood at a faster rate to ensure enough blood flows to them.
(This is why people feel dizzy on leg day – lots of blood flows to the legs from other body parts in a short period of time!)
Since this intensely exercises the heart muscle, then by definition it’s classed as cardio.
Can You Skip Other Cardio If You Do Leg Day?
So what you’re really asking here is:
If I do leg day, can I skip the treadmill or exercise bike?
Well, it depends on what your goals are.
If for example you’re training to help improve your athletic ability in a sports team, then you’d certainly benefit from aerobic training (running, cycling, etc.)
Whereas if you’re training purely to get shredded, then I’d focus on resistance training.
‘Cardio’ is not the best way to get in shape if you have limited exercise time. Intense weight training will always win if you can only train 3 times a week.
When Should You Do Other Cardio On Leg Day?
There is a correct time to do other forms of cardio on leg day.
If you’re going to do all your training in one session, always do your other cardio after your weight training.
Well, the other way around will hinder your lifting performance and limit the fat-burning effectiveness of the cardio.
(Many more fatty acids will be available for energy after weight training than before.)
Best Leg Exercises For Improving Cardio Fitness
Barbell Front Squat
- Stand tall with your chest up, with a barbell resting on the front of your shoulders, gripping it with either your hands crossed in front of your shoulders or your elbows pointing forwards.
- Keeping your chest up and core braced, squat down until your thighs are parallel with the floor.
- Powerfully push up to return to the starting position.
(Pro tip: Ensure that your hamstrings always touch your calves, and if you find yourself going up on your toes as you go down into the squat, then elevate your heels on a pair of weight plates.)
- Sit on the leg press machine, following its instructions to position yourself safely and correctly.
- Release the lock, then slowly lower the platform towards you by bending your knees.
- Push through your heels to straighten your legs and return to the start.
(Pro tip: Never ever lock out the knees on this exercise – 90% of full leg extension is ideal. This makes it safe and more effective.)
- Stand tall with your chest up in front of a long, clear pathway, holding a dumbbell in each hand with your palms facing each other.
- Keeping your core braced, take a step forward and lunge down until both your knees are bent at 90 degrees.
- Push off from your back foot and lunge forward with that leg, and repeat.
(Pro tip: If the movement feels ‘off’ as you stand back up, then start this exercise with just bodyweight.)
- Stand in front of a box.
- Bend down and jump explosively up onto the box.
- Step back down to the starting position.
- Straighten your arms out parallel to the floor with your feet shoulder-width apart.
- As you squat down, keep your core tightened and push your weight back into your heels while pushing your hips back.
- Keep squatting until your thighs are parallel to the floor, with your knees inline with your toes.
- Hold the position for 5 seconds, then push through your heels over the course of 5 seconds until you return to the starting position.
Sample Leg Day Cardio Workout
If you want an epic leg day cardio routine, then give this a try and tell me your heart is not working overtime.
Exercise 1: Leg Press (10 reps)
Exercise 2: Lunges (10 reps)
Exercise 3: Barbell Front Squat (10 reps)
Exercise 4: Box Jumps (10 reps)
Exercise 5: Bodyweight Squat (10 reps)
After each exercise, you should rest for 10 seconds until moving onto the next.
Once you’ve completed each exercise in the circuit, take a 3 minutes rest and then repeat a further 3 times.
In summary, a leg workout is a really effective (and challenging!) way of doing cardio.
Contrary to popular belief, cardio isn’t only running, biking and walking – it includes any exercise that exercises your cardiovascular system.
Hope this helped!
I’ve been in the fitness and strength training industry for nearly a decade. In that time, I’ve gained 30 pounds of muscle, written hundreds of articles, and reviewed dozens of fitness supplements. As for my educational background, I’m a currently studying for my Active IQ Level 3 Diploma in Personal Training.