I get this question all the time from clients, members or people who want more information, what is better: weight training or cardio? And to be honest there is not a right answer and it’s more complex than one or the other. They are both equally important for overall health and fitness. Cardiovascular work is important to maintain healthy heart function and blood circulation, and resistance training increases lean body mass, keeps bones strong and helps with metabolism in brief. One should not only do resistance training as well as one should not solely do cardiovascular training; it's a dichotomy.
I lean way more to the resistance side of the question, always have and always will, it is how I base my training methods and my clients. It does not mean I don’t perform cardiovascular work at all because it is greatly important to have an aerobic base or you can only get so far in your training. So yes, at times people need to do steady state aerobic work, but there are many ways to get the benefits of aerobic work with resistance training. Resistance training has been shown to decrease diastolic blood pressure, lower resting heart rates, increase cardiac output and stroke volume, increase mitochondrial function and more. Those are cardiovascular system improvements that lead to better health. The key to obtaining these results is the programming of the resistance training, using low reps and high weight and taking longer rest periods have shown no improvements of cardiovascular function, whereas using high repetitions, volume and shorter rest periods have shown improvements.
The goal of the aerobic system is to be able to produce a constant flow of energy and keep up with the demand of the environment (the workout or demand your body needs). When prescribing aerobic work it helps the person's overall capacity of work to increase. To increase capacity is to improve performance and health. Looking at it this way we can utilize resistance training to increase capacity in many ways, one of the best ways is through circuit training. A circuit of exercises and timed rest intervals will provide a heart rate stimulus that trains the aerobic capacity system. This circuit can be a minimum of 2 exercises and range to 12 exercises total. The goal of the circuit is not to lift as much weight as possible but to maintain a heart rate and increase work capacity. Heart rate is the important factor in making a resistance training program a cardiovascular program, we want the heart rate to be elevated over 130 beat per minute and able to sustain 130-150, doing this over the whole circuit will kick in the aerobic energy system to provide majority of the energy thus putting the demand on the system to change and improve for the next time.
To ensure that you are getting the cardiovascular effect the workouts must emphasize the full body to drive higher heart rates than just upper body exercises. Exercises such as squats and deadlifts are a must, due to the high drive for oxygen and full body use to perform the movements. The reps used to elicit the response should be 12 reps or higher with a cap of 30 reps, if you are able to perform 30 reps with ease then the weight needs to be increased. You want to pick weights that either you know you will hit failure at at 12-15 reps or lighter where it forces you to do higher reps that drive heart rate up.
Another way to train the cardiovascular system using resistance training that I use often is compound set (pairing) and triset with little to no rest in between the exercise movements to keep the HR elevated and then give a rest after all the exercises in the series is complete to let the heart rate recover and then repeat. This drives the demand of the aerobic system to kick in and provide energy once the other two energy systems cannot keep up with the demand for ATP. One of my favorite aerobic capacity workouts is 3 rounds of the following:
Jog/Bike for 6-8 min @ 70% intensity
12 x Squat
12 x Bench/Pushup
12/leg x Alternating Walking Lunge
12/arm x DB Row
12 x RDL
12 x Bicep Curl
Once you get done with the biceps curls its back to the beginning and repeat for a total of 3 rounds