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‘Cardio’ – Aerobic vs anaerobic exercise

“I need to do more cardio, Leila!’ I hear this statement all the time from friends, family and clients about how they ‘need to do more cardio’ for fat loss or, to lose weight. These statements are often said with no real understanding of what ‘cardio’ means except that it’s an arbitrary statement that’s been repeated over and over again in the health care community by doctors, nurses, stated in magazine articles and, in television. Most people don’t understand the difference between aerobic vs anaerobic exercise for fat loss or, how the body uses the aerobic or anaerobic system individually and, interchangeably.

Basically, our bodies use energy systems to run on and these energy systems are powered by the foods we eat in either a positive or negative way. Think about a car needing the correct fuel to keep running properly, our bodies do the same but in a much more complex manner. The fuel/food we put into our bodies is used by these energy systems to keep us doing all of our necessary daily activities as well as the exercise we do for fat loss. Having a better understanding of these systems will help you to activate your body’s energy producing metabolism to a higher degree.

Keep in mind though that increasing movement in any form which will increase your heart rate is a good thing including walking which, I think is one of the best things to do especially if you go walk/hike up a mountain. 😉

What is an Aerobic vs Anaerobic energy systems

Aerobic basically means ‘with oxygen’ and typically this energy system is used when exercising longer than 5 minutes such as running a full marathon. The Anaerobic system means ‘without oxygen’ thus oxygen is not needed and this system is used for durations of less than 2 minutes such as a 400 meter sprint. Each system works in concert together however, one may predominate another depending on what activity you are doing. Your body will go from one to the other for example when you start to run, at first it’ll use the anaerobic system for the first couple of minutes but then will transition to the aerobic system for a longer run. Your body uses carbohydrates for energy and thus fueling it with good carbohydrates like certain fruits, vegetables, and some grains is best for sustained energy usage.

Anaerobic exerciseThe Anaerobic system is utilized for exercises such as lifting heavy weights, plyometrics and short sprints. This is why your muscles start to accumulate lactic acid and fatigue, slowing down the muscle contraction after a short time when you sprint or do medicine ball throws rather than outlasting a steady state run like a 5 or 10K. My clients often ask me why they can jog or dance at a steady pace easier than some of the High Intensity Interval training workouts I have them perform, well.. this is why. It has to do with which energy system is being utilized but also to what degree you’ve trained in various sports like running vs sprinting. Take a look at a marathon runner vs a sprinter’s legs and you’ll see what I mean there is much more muscle development on the sprinters legs and butt.

So, what does it mean to do ‘cardio?’ A cardiovascular response is achieved whether you think you’re training in the aerobic or anaerobic system because they tend to actually be used interchangeably anyway. If for example, you want to do 5 sets of 30 second sprints for a workout with a warm up of a 1 mile jog, you’ll first use the aerobic then transition into the anaerobic system and then if you decide to walk between sprints for active recovery you’ll again be using the aerobic system.

Anaerobic exercise such as lifting weights helps build lean muscle mass which burns more calories at rest and, sculpt the body. Aerobic exercise such as longer runs or biking is great for improving mood, overall health benefits, and helps strengthens the heart and lungs. So, as you can see it is beneficial to do both types of exercise for a myriad of reasons but especially for an overall healthy sculpted body. Lifting weights in a circuit format is also a form of aerobic exercise if done quickly with not rest.

Different goals for different folks. If your goal is to gain muscle and burn more calories at rest then lifting heavy weights or, doing bodyweight exercise is ideal. If you are a novice and aren’t sure how to get started hire a personal trainer to help you or, to create a custom program for you.

Also, keep in mind that muscle does burn more calories at rest but it isn’t a ton more so don’t think it’s okay to go and binge just because you had a great workout session with your trainer or at the gym. People tend to not only underestimate how much they eat in a day but also to overestimate just how many calories they burn with exercise by as much as 600 calories or more.

Here is an example of a workout to build muscle where I use the anaerobic system in my ‘Back it up’ video to build muscle on the back and arms. If you want to increase your aerobic response with this workout you can do these exercises in a circuit format without rest between each exercise. If instead you’re looking to build more muscle do each exercise for 6-8 reps with heavy weights and rest for 1 minute for 3-4 sets then go to the next exercise.



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