Generally speaking, Cardio is the word used to describe exercise such as running, cycling, swimming, rowing or even just walking. No one is wrong in thinking this, but what people often forget is that the word cardio is an abbreviation of Cardiovascular; Cardio simply referring to the heart, and vascular is relating to blood vessels, so in theory any exercise which gets your heart pumping and increases blood flow is cardio, regardless of what it is your doing.
When you do cardio or ‘cardiovascular exercise’ to give it its full title, your breathing rate increases to facilitate the removal of carbon dioxide and inhalation of oxygen, and your heart rate increases to increase blood flow to the muscles to supply the oxygen needed for the production of energy. Your body temperature will increase and you may begin to sweat as your body attempts to remove excess heat created by the increase in aerobic output. Cardio will improve the health and strength of your heart, as well as lowering blood pressure and help prevent the risk of heart attacks and heart disease. Also, due to the increased demand for energy required by the body to perform cardio, it may help with fat loss, although this will largely depend on the type and intensity of cardio you are doing, as well as the quality of your diet and your overall lifestyle. The benefit of this being that the less fat you carry the healthier you are likely to be which will reduce the chance of you developing weight related illnesses such as Type II Diabetes and some forms of cancer.
So far so good, but the benefits stated above are non specific. By that I mean that not all forms of cardio will have the same effect(s) on the body. Too much of any form of cardio will lead to muscle loss which will have a negative effect on body composition and fat burning potential. This is due to a number of factors, one of which being the release of Cortisol which is a hormone which promotes the storage of fat and burning of muscle. Your body also tries to adapt to the demands of cardio by reducing muscle mass, because muscle is a dense tissue, so your body sacrifices this heavy weight in order to be more efficient. Another point worth a mention is that high impact exercise such as running can have a negative effect on your joints and cartilage, making you more prone to injury. Injuries are common in any sport, but more so in those that involve long periods of aerobic exercise such as running. Think about someone who runs a marathon; chances are that either during training or during the marathon itself, they will experience some form of injury which will prevent them from exercising for anything from a couple of days or weeks, to even months. Most of these injuries aren’t caused by just one run, but by months or years of repetitive stress caused to the joints, muscles and bones, with the most prone areas to injury being the knees, shins, hips and lower back. The words ‘stress fracture’ and ‘shin splints’ come to mind! Our bodies simply weren’t built to run for long distances.
I see a lot of runners with very poor posture. This is mostly due to muscle imbalances caused by overuse/underuse of certain muscles. As a bodybuilder you would never contemplate training just one part of your body several times a week, but people who run as their only form of exercise are in effect doing just that. If you’re a runner, you probably don’t care much about how much muscle mass you have, or whether or not you hold a bit of extra fat around your waist, as long as you times/distances keep on improving. And I don’t have a problem with that, but the truth is that MOST people who run do it in the belief that it will help them lose fat and improve their health and fitness. To a degree it will, but it will not get the kind of body composition MOST people set out to achieve which is strong and shredded.
I’ve maybe gone a bit off topic, so to go back and answer the original question ‘Do we really need to do cardio?” the answer is definitely YES. However, this is when the definition of cardio comes into play...
You DO need to do physical activity which elevates your heart rate to primarily keep you fit and healthy, and to help burn unwanted fat, but you do NOT have to do activities such as running and cycling in order to perform cardio. If you haven’t already guessed what I’m getting at, ask yourself what happens when you complete a challenging weights routine at the gym? Your heart rate increases, your breathing becomes quicker and deeper and you build up a good sweat.....sounds very much like cardio to me! Therefore, should weight lifting not be classed as cardio? I would argue that it should, and with the many positive effects of weight lifting on your body composition and general health, is other cardio exercise such as running totally necessary? To answer that question would partly depend on your own goals and preferences. Obviously if you intend to run a marathon then there is no way around the fact that you will have to engage in a lot of running, but can you be fit and healthy without spending hour after hour stuck on the treadmill? Of course you can; it’s all about HOW you train, as much as WHAT it is you do.
How to turn a weights session into Cardio
Standing around a pile of dumbbells and randomly doing a few reps won’t make your body work hard, but concentrating on compound lifts, putting in maximum effort, with minimum rest periods, using a relevant weight for the rep range you are doing will soon have you gasping for breath in the same way any sprint on a treadmill or bike does. Make sure you incorporate drop sets, supersets, giant sets, circuits, rest-pause, partial reps and occasionally forced reps to help keep the intensity of your workout high and physically challenging on both your muscles and circulatory system.
I want to make it clear that I am NOT totally against ‘traditional’ cardio such as running, but I want people to understand that weight training is just as good a form of cardio as any other, as well as being one of the safest and rewarding of all physical exercise for both your health and physique. Running and other forms of cardio definitely have their time and place, but I don’t believe they should be the focus of your training. By all means add cardio to your weekly routine if that is what you want to do, but with all the benefits of weight lifting on body composition and health, and the possible negative effects of too much running etc on your body, I don’t deem it NECESSARY that you do make time for ‘traditional’ cardio, as long as you do make sure you do something which increases your heart rate and pushes your body then you can still be healthy. Obviously you also need to consider the food you eat, the lifestyle you live, and the body/goals you want to achieve when deciding what form of cardio you do, but you can still be fit and healthy without clocking up mile after mile on the treadmill.