If we were speaking in absolutes, and you had to choose one over the other, I would recommend prioritising lifting weights over cardio for a variety of reasons.
If you’re an absolute beginner, untrained and unfit, I would most definitely prioritise lifting weights over cardio. As a beginner, lifting weights alone will build muscle, help you get stronger and initially also increase your V02max. It’s also much more efficient for improving body composition than cardio.
It’s also known that the body’s adaptations to resistance and aerobic training are highly specific, so lifting weights will build or retain muscle while cardio training will likely improve VO2max.
So, if you were an elite power or physique focused athlete, such as a bodybuilder or powerlifter, it makes sense to keep cardio to a minimum for the purposes of building or retaining muscle and strength.
But if you’re like most people who don’t quite fall into either category, and you want to reap the benefits of improving your cardio metabolic health, and increase your aerobic capacity, then doing cardiovascular exercise is a viable option for you.
We know that short term, there isn’t much of a benefit seen in resistance training, and studies have shown that over the course of 12 weeks, a combination of both resistance training and cardiovascular training may be best for fat loss and overall “fitness”, which makes sense as to why it’s recommended to most people in the obese or overweight category.
However, we also know that the body adapts to both cardio and resistance training, and that you shouldn’t simply be looking at the immediate 12 weeks, but rather look at training as an ongoing thing. So, it makes sense to adjust your training program to your specific goals along the way.
Whenever we review scientific literature it’s important to remember that most conclusions are context dependent, and that we are often NOT speaking in absolutes.
So, it’s not really possible to make a blanket recommendation about whether or not everyone should or shouldn’t be doing cardio, but if you enjoy it, and it’s conducive to your overall goals, then keep it up. If you do cardio as part of your training to improve body composition, don’t get too caught up in the type of cardio you should do, as it also makes sense to do what you prefer.