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Hard Cardio for Weight Loss

In this Vision Personal Training article, our experts discuss the importance of hard cardiovascular activity and how it assists in weight loss goals.
Weight Loss Articles
Weight Loss Articles

By Daniel DiMattina at Templestowe

When talking about weight loss, cardio training is essential for great results because the repetitive nature of the exercises allows the body to work at a greater metabolic state for long periods of time, particularly compared to weight training. This heightened energy expenditure burns through the body's energy stores, including the much-despised body fat stores. Many of our awesome clients in the Vision Personal Training network have gone on to complete half and full marathons, triathlons and other endurance feats taking upwards of 2 hours to complete. It would make sense that the longer time you spend exercising the faster you lose fat, right? Why then does your exercise program contain a requirement of 'hard cardio'? The type of cardio that you can only do for a few minutes at a time before needing a breather. Would it make more sense to add more low to moderate cardio where you can work not only for longer periods, but also complete the training without needing a rest?

 As with most things in life, the more you put into your health and fitness journey the faster you will achieve some incredible success. If you go for a jog for a few hours a day every day, spend another couple of hours measuring/weighing every portion before prepping your meals to fit your VVT food plan that is awesome! Add in another hour or so for stretching and recovery based activities, the chances are very high that you will see some results happen quite fast. Chances are also very high that for the majority of you reading this, the above lifestyle is very impractical. Your other interests and commitments require your time as well. One of our main objectives is to provide you with all the required pieces of the puzzle that is achieving your desired result, whatever that may be. We also know that the more efficient and convenient the process is, the more likely you will be to follow your program. Enter 'Hard cardio.' This type of training is not only time efficient, it can actually be more effective at achieving fat loss than your standard low to moderate intensity.

 So, what is hard cardio?

The distinction between light, moderate and hard cardio is generally made via heart rate ranges. The higher the intensity of exercise, the higher the required additional fuel and oxygen needs will be. According to the Fitness Australia Exercise Guidelines, moderate intensity cardio is defined as 40-60% of HRR*, while vigorous intensity is 60-85%. In practical terms, hard cardio will result in heavy, rapid breathing, a noticeable throbbing in the neck where your pulse can be felt and depending on fitness level can only be sustained for a few minutes at a time. If you're able to have a chat with your trainer, ramp it up a bit!

How it is effective.

When talking about losing fat, a good way to look at the process is similar to how a car operates. Eating food puts energy into the body just like filling the car up with fuel gives it the ability to move. How hard we push our body during a session will also resemble what happens when you put the pedal to the metal! The sudden change in energy demands will cause the body to mobilise its fuel sources in large amounts to compensate. In effect, you burn through your fuel sources (carbs and fats) at a much faster rate.

How it works.

The body functions extremely efficiently. At rest and during light activity, the body utilises oxygen to break down carbs and fats completely, meaning less amount of fuel is needed per 'yield' of energy. When you are exercising at high intensity, the body requires more energy at a faster rate. So much so that the demand actually exceeds the amount the body can produce via its AEROBIC, or oxygen energy system. It therefore goes to plan B and engages its ANAEROBIC system. This allows fuel to be partially broken down to produce energy at a very fast rate without oxygen being present. However, as the fuel is only partially used, larger amounts of it are needed to provide the equivalent amount of energy as with oxygen!

 What does the science say?

In general, it is hard to distinguish between whether hard cardio or slow, continuous cardio is more effective at losing fat. In effect, you're comparing apples and oranges due to differences in intensity and duration of exercise. What is clear is that both forms can be effective if implemented correctly, with hard cardio also offering some other additional health benefits. In one study conducted with a group of females aged 18-30; a 20 minute HIIT** program was tested against both a 40 minute slow, continuous cardio program and a non-exercise control group over a period of 15 weeks. The study found that:

  • The HIIT program resulted in an average loss of 2.5kg of fat mass while the other groups actually gained an average of 0.3kg of fat!
  • The HIIT resulted in a significant drop in fasting insulin levels, an important factor in Diabetes risk.
  • While both exercise groups significantly increased their average peak aerobic power (the ability to work at a higher intensity for longer), HIIT resulted in a higher score compared to the continuous cardio program.
  • Another interesting point was that while nutrition was controlled, there was no prescribed food plans given. Imagine how much better the results would have been if combined with a tailored nutrition strategy from Vision PT!


While hard cardio can have an amazing impact on your health and fitness, it is quite a demanding form of exercise. For the everyday person, hard cardio is recommended 2-3 times a week while light to moderate cardio is recommended to be completed a minimum of 5 times (ideally every day) per week for 30 minutes or more. To change any habit, including exercise and lifestyle ones, an important factor is doing the right thing as often as possible. Completing too much hard cardio can lead to feeling sore, lethargic and often very hungry! This may have a negative effect of your nutrition, which we know contribute 70% of achieving your goals. Therefore, Vision recommends completing 25% of your total cardio targets in that hard-cardio bracket. This means you are able to supercharge your fat loss without the risk of not properly recovering from sessions and sticking to your nutritional strategy which can result in overuse injuries and a stall in results.

For more information on this and any other health and fitness related topic always feel free to speak to your Trainer or head in to your local Vision Personal Training Studio to kick-start your journey to feeling amazing!


*HRR (heart rate reserve) is calculated by subtracting your Resting Heart Rate from your Maximal Heart Rate

**High Intensity Interval Training - a form of hard cardio


*Disclaimer: Individual results vary based on agreed goals. Click here for details.

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