Why do cardio? Everything you need to know to get started (again)

Cardio isn't just about running on a mat to work up a sweat. As part of a fitness routine, a weight-loss program or as a stand-alone activity, cardio training has its place in our daily lives. It's even hidden away in non-sporting physical activities like housework! 

Cardio-training is the key to physical performance and cardiovascular health. It protects the heart and lungs, improves blood circulation, plays a role in managing body weight, helps you sleep better... There are many reasons to exercise your heart muscle. 

Strengthening your cardio means strengthening your immunity. That's why it plays a central role in the quest for good physical condition. Running, cycling, rowing, brisk walking: each training session helps the body burn fat and build muscle mass, while releasing hormones that promote well-being.

When practiced regularly and adapted in intensity, cardio is a way to perform and transform your health. From WHO recommendations to ways of doing it, here's why and how to do cardio, whatever your goal.

What's the point of cardio-training?

What is cardio in sport?

Cardio is a form of physical exercise known as cardiovascular exercise, because it works both the heart and the lungs.

During exercise, the body needs more oxygen and nutrients. The heart accelerates its rhythm to pump faster and provide the body with what it needs to adapt to exertion.

This cardio capacity depends on individual genetics, age and sex.

Adapting to exercise with cardio

Doing cardio increases several physiological functions:

• heart rate ;
• blood pressure ;
• oxygen consumption;
• body temperature. 

Cardio strengthens the heart muscle. The heart acts as a pump, pumping blood throughout the body via a vast network of blood vessels. Together, these make up the cardiovascular system. 

Just as the heart rate accelerates, physical activity also increases the respiratory system to renew the air faster and oxygenate the blood better. 

Cardio exercise stimulates the body's cardiovascular and respiratory systems, enabling itto adapt to the effort involved. 

Are cardio and cardio-training the same thing?

Yes, both terms refer to a form of physical activity that involves the heart muscle and increases heart rate. The term "cardio training" translates as " heart training", and helps to strengthen the cardiorespiratory system.

A multitude of exercises give you the chance to do cardio, at high or low intensity, such as cycling, running, swimming, fitness, etc. 

What is a cardio session?

There are many different ways to do cardio: outdoors, indoors, in the weight room, and so on.

We can distinguish those that are practiced :

• standing and require the body to bear the additional load of the body: walking, running ;
• sitting or lying down: swimming, cycling ;
• using specific equipment : elliptical trainer, rowing machine, treadmill, etc;
• intermittent training, such as hiit (High Intensity Interval Training).

What is good cardio?

What does good cardio mean?

A good cardio system means a cardio-vascular system in top form. The latter transportsoxygen to the organs continuously, day and night, whether you're exercising or reading. In short, all the time. The more intense the activity, the greater the quantity of oxygen required by the muscles.

So, if the cardio system is working well, the cardiovascular system enables the body to adapt more quickly to the effort involved.

We're not all born equal when it comes to our cardiovascular capacity, but the good news is that it can improve at any age.

There's no reason not to start, especially when you know that the progress you make through training is also useful in everyday life. Endurance is good for your health!

Indicators of a good cardio system

How do you know if you have good cardio or not?

The reference measurement is heart rate (HR), often expressed as a percentage of maximum heart rate (HR Max) to measure exercise intensity.

In theory, FC Max can be measured using the traditional formula FC Max = 220 - age, but nothing beats a maximum heart rate test, which is more precise, as the formula has a margin of error of plus or minus 20%.

In any case, to work on your cardio, you need to be regular, which is the only way to improve your capacity over the long term.

CF zones	Intensity level	FC Max	Impressions
1	Very low	50 to 60% of FC Max	Very easy, ideal for starting a warm-up or for active recovery.
2	Low	60 to 70% of FC Max	Easy to use for prolonged effort, active recovery or general fitness improvement.
3	Average	70 to 80% of FC Max	Medium-difficulty, more demanding, interesting for improving endurance.
4	High	80 to 90% of FC Max	Difficult, can be used to build endurance at high speeds and over shorter periods, to increase aerobic and anaerobic capacity.
5	Very high	greater than 90% of FC Max	Very difficult, as it's close to maximum heart rate, i.e. maximum threshold. Can be used to work on anaerobic capacities.

In addition to HR, heart rate variation (HRV ) is another indicator of good cardiovascular health. HRV is sometimes referred to as cardiac variability. It corresponds to the variation in time between two heartbeats over a given period of time^.1

A low VFC becomes a risk factor for cardiovascular problems and worsening cardiovascular disease.

Why use cardio for everyday sport? 

Benefits for cardiovascular health

The heart is a muscle, and like any other, it needs training to improve its cardiac performance. It performs vital functions for the body, such as transporting oxygen and nutrients, and eliminating waste and CO². 

In addition to reducing the risk of cardiovascular pathologies (high blood pressure, heart attack, etc.), strengthening the heart muscle also improves blood circulation and protects artery health.                            

The impact of cardio on body composition

Cardio-training plays an important role in weight management, both during weight loss and stabilization.

Doing cardio burns a lot of calories and fat as the intensity of the exercise increases. What's more, what's known as theafterburn effect also continues to burn calories after the cardio workout. 

It's one of the essential elements for losing body fat and improving body composition. 

Cardio: an asset for endurance

The more you work on your cardio, the longer you'll last, because you're improving your lung capacity.

In all disciplines requiring prolonged effort, such as tennis, basketball or soccer, cardio plays an important role in effort management. 

Cardio training is also essential to prepare the body for intense effort. For example, sprinters or gymnasts need to do cardio to warm up their heart. 

Positive effects on mental health

Cardio, and physical activity in general, helps reduce stress and anxiety levels, thanks to the release of endorphins. 

For adults and children alike, regular training also boostsself-esteem and has a positive impact onmood. The beneficial effects on sleep and sleepiness have also been proven. 

For all these reasons, and more generally, cardio sports promote mental health².

The benefits of cardio for recovery

Low-intensity cardio as part of active recovery maintains a higher heart rate than at rest.

This mechanism is conducive to the elimination of metabolic waste and helps the body recover more quickly, although recovery times vary from discipline to discipline.

Impact on the immune system

The body perceives physical activity as a positive aggression to which it reacts with what is known as an immune response.

During physical exercise, muscle fibers secrete myokines. These substances have a beneficial effect on health. Some even play a role in the improvement of certain chronic pathologies^.3 

Conversely, physical inactivity alters their release and induces a pro-inflammatory state favoring sarcopenia and fat accumulation.

That's why every cardio exercise boosts the immune system. 

How to optimize your cardio workout? 

Structuring your cardio-training workout

The recommendations of the World Health Organization (WHO) differ according to age:

• For children, a minimum of 60 minutes per day, all week long, of moderate to sustained aerobic intensity is required;
• for adults, aim for 150 to 300 minutes of moderate-intensity activity per week, or 75 minutes to 150 minutes of sustained activity.

And that's a minimum, since adults can double the amount for "substantial health benefits". To this, the WHO recommends adding muscle-strengthening activities, the number of which varies according to the population (children, adults, the elderly).

Ideally, these times should be broken down into 5 sessions of 30 to 60 minutes of cardiovascular activity per week. If that sounds like a lot, the good news is that it also includes all physical activities such as walking to run an errand or doing household chores. 

Choosing the right time for cardio

The right time to do cardio is above all when you feel like it.  

There are no studies recommending a preferential time slot between morning and evening. On the other hand, the positive effects of training on sleep and circadian rhythms occur if it is practised between 4 and 8 hours before falling asleep^.4 

The idea that late-night exercise disrupts sleep is false. Even late-night exercise is better than no exercise at all. The benefit-risk ratio is heavily weighted in favor of physical activity.

Cardio without running

There are many ways to work on your cardio: running, cycling, swimming, rollerblading, brisk walking... You don't have to run to build up your heart.

Fitness disciplines such as zumba or step are alternative ways to get some cardio in without running. Some can even be done without impact, like certainaerobic movements which, when linked to rhythmic music, can quickly raise the heart rate!

Dancing is another form of cardio that saves you from having to put on your running shoes. No matter what style you choose, from salsa to hip-hop to jazz, you're sure to get your heart pumping - and work on your flexibility in the process.

2 mistakes to avoid with cardio-training

Mistake No. 1: Too much restless cardio

The most common mistake is overtraining. A series of over-intensive sessions, with little recovery time, can lead to an accumulation of physical and mental fatigue. 

The signs that invoke it are (among others):

• not being able to produce the same effort as usual;
• poor sleep;
• lack of motivation ;
• irritability.

To avoid it, rest periods are mandatory and part of sports performance.Diet and sleep are also important factors in avoiding this syndrome.

Mistake No. 2: A lot of cardio too fast

The second mistake to make when you start doing cardio is to want to go too fast all at once... and then get bored.

When starting an activity, you need to build up gradually. For example, people returning to cardio after an injury or a long break such as maternity leave can start with a workout alternating brisk walking and short runs (3 minutes of each, in 3 to 5 sets).

Trying to do too much at once can lead to injury or demotivation. It's important to remember that cardio training is a long-term, regular process.

Do you need to combine cardio and weight training to perform? 

The performance suit

The combination of cardio and strength training is an effective way of making long-term progress.

Cardio improves endurance, recovery and cardiovascular health. Weight training develops strength and power. Together, they work on body composition and optimize overall performance thanks to :

• a stronger, more efficient heart ;
• strong muscles ;
• better use of energy during exercise.

Energy pathways in cardio

Depending on the duration and intensity of exercise, the body will use different energy reserves, mainly carbohydrates and fats. Their use varies according to the energy channels involved.

Effort phase	Dominant energy sector	Substrates used	Exercise example
0 to 10 seconds	Anaerobic alactic	Phosphocreatine	Sprint, jump, explosive start
10 seconds to 2 minutes	Anaerobic lactic	Carbohydrates (muscle glycogen)	HIIT, intense running, hills
+2 minutes	Aerobic	Fats + carbohydrates	jogging, cycling, brisk walking

At the start of exercise, and if the effort is intense, the body activates the anaerobic alactic pathway. This provides immediate energy thanks to the phosphocreatine reserves stored in the muscles, but is exhausted in a matter of seconds.

The body then activates the anaerobic-lactic pathway to sustain intense efforts lasting several minutes. It draws on its carbohydrate reserves (muscle and liver glycogen) to produce energy without oxygen, but retains a minimum of carbohydrate to maintain blood sugar levels.

As the effort continues, the body attacks its lipid reserves by activating its aerobic pathway. The latter dominates endurance exercise , promoting the breakdown of fats to produce energy, known as lipolysis.

Cardio-training exercises therefore mobilize lipids, including intramuscular triglycerides stored in the ^muscles5, and the more you exercise, the faster lipolysis is activated. 

That's why athletes add cardio sessions to their muscle-strengthening training. The latter, whether practised with or without equipment, is essential for preserving muscle mass and strength. 

Our tips for getting back into cardio

As we saw in this article, there are many reasons to get back into cardio late in life, or after a long break. There's no age limit for getting (back) into it, and progress is made through regular training.

To build up or regain endurance, it's essential to take up cardio gradually, focusing on short, low-intensity sessions to avoid injury.

Warming up at the start of your workout is essential, as is monitoring your heart rate to ensure you stay within your endurance zones.

Last but not least, make sure you seek medical advice, especially for those with a history of cardiovascular problems or persistent pain. This also applies to those who have decided to take control of their body and have never exercised, or not for a long time.

Conclusion

So why do cardio?

While its main role is to shed fatty tissue by using lipids as an energy source, it's not just there to burn fat. Cardio-training is a tool for cardiovascular health, mental well-being and sports performance. Exercise stimulates the heart, lungs and blood circulation, improving endurance, boosting immunity and promoting better sleep.

To lose weight, gain energy or maintain your health, you need to incorporate regular cardio sessions (brisk walking, cycling, swimming, HIIT, dance...). These should be done regularly and progressively to optimize your physical and mental capacities.

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