Cardio for weight loss: how and when to do it.

When I first started exercising (at the age of 16), I was severely overweight, and my favorite hobby was spending ten hours a day playing World Of Warcraft. As soon as all my friends started being more interested in girls than computer games I thought that maybe I should do the same. The problem was that approaching girls with a body that resembled Jabba the Hut was scarier than jumping off a cliff without a parachute. 

I knew I had to lose weight if I wanted to have even the slightest chance of being successful in finding myself a girlfriend. 

One of my classmates at that time had just been through a radical body transformation, losing more than 20kg (3+ stones). Not knowing where to start from, it seemed like a good idea to ask him for advice. He told me to eat as little as possible, stop sitting in front of the computer and walk more. 

Without even questioning his knowledge, I jumped on his starvation+walking plan. I lost 10kg, maybe more, but eventually, the scale stopped moving. I couldn't lose any more weight despite eating 1000kal perhaps a day. 

At that point, I was still determined to lose more weight, and I didn't know how to do that. That's when I decided to take a more drastic approach. I read somewhere that running was one of the most calorie-consuming activities, so I started to run. 

I would run for at least two hours every day,  pushing myself to the limit and trying to eat as little as possible (sometimes as little as one small meal per day) which eventually led me to develop some severe health problems.

This approach worked at first. I dropped five more kilos, but again, after a month I got to the point where it didn't matter if I was running two or three hours each day, my body wouldn't change. 

I was hungry, tired, frustrated, and terrified by the idea of gaining that weight back. 

It took me years of trial and errors to break free of the train more + eat less mentality.

Today I can finally say that I know how my body and brain work, and I can use cardio in a smart way that is effective and doesn't damage my health and mental freedom. 

Now that you know my story let me explain what cardio is and why you should do it smartly. 

What is cardio? 

Cardio training is any activity that increases the need for oxygen in your body while moving. A simple way to understand this is to think of any activity that increases your need for breathing and eventually makes you sweat. 

The increased need for oxygen within your muscles stimulates an increase in your heart rate, it also stimulates an increase in your body temperature, and eventually, you will start to sweat. 

Think about the last time you were walking fast on your way home while carrying some grocery bags. Your breath got more oppressive, palms sweating and a mild sense of fatigue was permeating your body while walking the last 100 meters before reaching your door. You dropped the groceries on the table, took off your jumper, and noticed that your lower back was still a bit sweaty. 


The biggest misconception about cardio is that you have to be on a treadmill or be running outdoor while actually, any activity that pushes your body outside of your regular resting heart rate is indeed a sort of cardio. 


Different people have different cardio thresholds. The fitter you are the harder it is to raise your heart rate because your body has developed a better capacity to carry oxygen. 

That's the reason why someone that hasn't exercised in the last four weeks (and has a sedentary lifestyle) will get short of breath and start sweating very quickly, even by simply walking at a fast pace. 

In my case, when I first started to lose weight, I have managed to drop my first kilo by merely walking on the treadmill.

After a couple of weeks, my body got used to that, and I couldn't see any drop in weight because I wasn't pushing myself any further. That's when I started running and doubled the amount of time I was spending at the gym. That worked at first but, as it happened before, my body got used to it and, at that point, there was very little room for improvement. 

I couldn't run more than two hours at a time without collapsing. I had rushed the steps, and I found myself hitting a plateau. 


The one lesson I want you to take here is that YOUR BODY ADAPTS TO EVERYTHING YOU DO 

If you don't consistently push yourself a little bit more you won't see any change happening. If you rush the steps and try to increase the intensity (or the length) of your sessions too quickly, your body will adapt, and you will hit a plateau. Neither too little nor too much will get you where you want to be, the middle path is the right path. 


How should you approach cardio? 

First of all, you need to find some enjoyable activities. Keep in mind that fat loss occurs slowly, and you will need to perform some physical activities three to six times per week for 20-40 minutes at a time. If you don't find something that you enjoy doing, you will most likely give up before any real results can show. 

It is essential that you AT LEAST DON'T HATE whatever activity you chose. 

This is a list of my favorite ones: 

* Spin bike while reading a book

* Walking up e down the stairs in the morning 

* Bike ride in the park 

* Different types of gym classes 

* Medium speed cross trainer while watching a TV series on my phone 

* A very long walk in nature (unfortunately I can't do that daily)

*Walking your commute to work

Other options that work just as fine are:

* Team sports 

* Skipping 

* Sprinting 

* HIIT training 

* Circuit training / CrossFit 

Note: I don't count weight training as a type of cardio, (even though it's fat loss benefits are remarkable) but that deserves a separate discussion. 


After you've chosen your favorite type of cardio activity, you need to keep the intensity of each session under control. I like to do my cardio at a moderate intensity (70% hrm). That means that if I had to have a chat while doing it, I would get moderately short of breath and I would start sweating but not dripping. 

At this intensity, I am sure that my body is utilizing a good amount of body fat and blood sugar to sustain the activity and I'm burning calories at a rate that won't make me feel exhausted. 

Be aware that a beginner (especially if overweight) would reach that intensity rate by simply walking fast, and that's OK. Getting fit happens in a matter of weeks, but real fat loss takes months, so make sure that you start softly and progressively increase the intensity (and length) of your cardio sessions each week. 

I don't like very intense forms of cardio (for fat loss purposes) because they make me feel hungry and exhausted. I've learned that a moderately intense cardio session has way more benefits when it comes to weight loss, and it's generally more physically and mentally sustainable. 


Consistency is paramount, and starting little will assure you more significant progress. If you haven't exercised more than four times in the last month, consider yourself a beginner and be OK with it. I often see people that used to be very active (but they stopped exercising because of work) trying to go all in and fit six sessions per week. They usually end up burning out and quitting. Be smart and take the necessary time to give your mind and body the ability to implement this new habit. 

A good structure could be:

Week 1: 2x25 minutes 

Week 2: 3x25 minutes 

Week 3: 3x30 minutes 

Week 4: 3x35 minutes 

And so on. You can build up to 6/7 session of 45' per week, even though that's usually not necessary. Once you develop the habit of getting your cardio done, you can play with the intensity and the length of your sessions and test new things, but don't rush the process! 


If you measure your heart rate while doing cardio (you can easily do that on any piece of equipment at the gym), you will see that the more sessions you do, the more speed/resistance you will need to get to 70% of your Hrm( heart rate maximum). That means that you're getting fitter. At this point, it's a good idea to not just increase the length of your sessions, but also the intensity. 

Try to get your heart rate in the range of 115-125 bpm (beats per minute). At this heart rate, you'll be sweating and get mildly short of breath but not exhausted. You can easily keep this intensity for up to 45 minutes. 

Use this as a general rule : 

- After the first 10 minutes, you should start to sweat  

- After 20 minutes  you should begin to feel an energy kick 

- After 30 minutes you should feel high 

- After 40 minutes you should feel slightly tired 

- After a shower, you should feel hungry 


The time of the day that you pick is highly dependent on your schedule. Fasted cardio in the morning burns more calories, but if your working shift starts at 8 am you should probably wake up at 6 am to get it done. Ask yourself if that's something you would enjoy doing. If the answer is no, try to find a time that won't feel like a punishment. 

I like to do fasted cardio with my wife during the weekend and have an excellent breakfast together. During the week, I cycle to work, run in the park, and sometimes I may jump on the cross trainer after my weight training sessions. I am very flexible with the type of cardio I choose. 

It doesn't matter what time or what kind of cardio you do as long as I get it done. 


Learn to be flexible. If you planned to do 3x35 minute sessions this week but, because of some inconvenience you had to skip a session, you can always do 2x45 minute sessions and catch up the 15 minutes you missed this week by increasing the length of the sessions you're going to do next week by five minutes each. 

Don't limit yourself to a single type of cardio. If you skip one session you can always go for a run, walk up e down the stairs of your flat, do some bodyweight exercise routine at home, or go for a long walk at a quick paste. 

Even the busiest person on the planet can sneak in a 20 minutes run. Stop telling yourself the story that you don't have enough time and get creative.


This is a very personal question, and it highly depends on many variables like food intake, metabolism, age, and sex. Who promises you a certain amount of weight loss if you follow a workout and a cardio routine is a liar. There is no way to predict how much weight you will lose, but there is a way to track your progress and adjust your food and level of activity according to your weekly weight variations. 

We use the Kf-fit tracking system to monitor weight, body measurements, food intake, and level of activity of our clients. Having this information allows us to make smart decisions on whether or not it is a good idea to decrease the food or to increase the length of each cardio routine for that particular client.

Always remember that everything may work and everything may not work; it all depends on you. Take the necessary time to get to know yourself and build a sustainable and enjoyable cardio routine.