People draw a clear line in their minds about cardio and strength.
Cardio: running, walking, cycling, swimming, jump rope, stepper, elliptical, rowing, burpees, stairmasters.
Strength: dumbbells, barbells, push ups, squats, pull ups, pulleys, cam-based machines.
The thinking goes as follows:
I warm up with cardio
Or
My doctor wants me to do only cardio so no squats, push ups.
Or
I want to lose weight so cardio is the best right?
But the line between the two is far from clear and distinct.
Let’s play a simple game: do 20-25 quick and deep squats. Is your heart rate up? Or you breathing a little harder? Congrats you just did a little ‘cardio’.
20-25 too easy? Bump that number up to 35-40. What happened to your heart rate now? Are you doing cardio now? Or are your legs a little shaky and burning a little?
Cardio refers to cardiovascular training does not depend on the activity you are doing.
The exertion is measured by the amount and kind of work your heart is doing.
It could be very hard work for short bursts of time. Or relatively lighter work for longer bursts. And everything in between. As measured by your resting heart rate, age, vo2 max, heart rate recovery among other measures.
You can use any activity to achieve those outcomes. And it will be very very hard to draw a line as to where the adaptations are strictly for the heart. Movements we think of as economical like walking, stepping, running, elliptical, cycling, pushing sleds that don’t make muscles of the legs, back or arms fail or fatigue excessively are more reliable ways to place a controlled, sustained stress on the heart.
Strength training is measured by force produced or how hard you are resisting against gravity. There are different types of contractions. You can use different ranges of motion. Different kinds of exercises. Different kinds of tools and machines. All in service of making muscles contract, react and work in controlled ways. And your heart is working quite hard to ensure oxygen reaches these muscles that are plugging away at a movement.
Cardio and strength training go hand in hand. There’s always some degree of one while you are performing the other.