The purpose of cardiovascular exercise is not to make you sweat or burn calories. Unfortunately it has been used for these purposes throughout my 20 years in the fitness industry. From step aerobics and spinning classes to bootcamps and HIIT I've taught all the classes. And this means I've seen the results, or lack of, in numerous people.
Nowadays there's a huge push towards high intensity interval training. However most HIIT classes aren't what they say they are. And there's much more to cardio than just making yourself tired.
Now, on the other side there's low intensity exercise like walking. Unfortunately it too is being used for the wrong purposes. I can't tell you how many people I've sat in front of during our initial consultation who tell me they walk daily, yet they aren't happy with their weight, body shape and/or energy levels. They may be fit for walking but they are missing out on being fit for life.
There's also a big emphasis on lifting weights which is great, especially when people over 50 are embracing it. Lifting weights to strengthen and build muscle and bone can go a long way to helping your longevity. But it's not, or should not be the only component of an exercise plan.
All cardio exercise is not equal. Different things happen at different intensities. Walking is great for recovery and mental health but unless you're marching at a pace where you are significantly raising your heart rate it's not going to build a good foundation of aerobic fitness.
Training at higher intensities has great benefits to strengthen your heart and help with stress tolerance. But too much stress, as is the case with many high intensity exercise classes, will ultimately result in reducing your energy and overall wellness.
Surely anything is better than nothing, John? I hear you ask. At the start of your exercise journey, maybe, but I've met many people who've tried 1 session and found it far too tough to keep up. They've told me it turned them off exercise. So in that case it wasn't better than nothing!
For long term, noticeable results we need to be more purposeful with our exercise. Developing a strong level of fitness will help us deal with the stress of life. And I'm not talking about letting off some steam in a session. While that can have some benefits mentally it may not help us too much physically.
To better understand this it's important to take a look at what exercise at different intensities does to our bodies and what happens afterwards.
All exercise is a stress to our bodies and stress primarily impacts our central nervous system. The CNS has 2 main branches, the sympathetic better known as fight or flight, and the parasympathetic also known as rest and digest.
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Fight or flight is an evolutionary survival mechanism. Something needed to happen when our ancestors were faced with a threat, like a lion. So in order to survive our bodies have evolved to
- Increase heart rate to pump more blood (energy) around the body
- Increase breathing rate to supply more oxygen to the blood
- Break down energy stores in the body to supply fuel to the working muscles via the blood
- Shut down many processes that aren't immediately needed for survival, like digestion
This is known as a catabolic state, essentially your body is in a state of breakdown. You can also see that this is exactly what happens when we exercise.
Short term stress can be very beneficial to us. Because once the stress is over our bodies can learn to deal with it for the next time by making us more capable.
However, if we add more stress on top of stress we don't get a chance to adapt to it, instead we get more stressed. Also, many of today's stresses are mental rather than having to run away from a lion. They are perceived threats rather than real threats to our life. And we tend to carry this mental stress with us long after the fact. The thing is all stress, whether it's physical or mental, real or perceived, results in the same physical responses mentioned above.
All this leads to a state of chronic stress, a state in which our bodies are in breakdown more often than not. Then when we try to add exercise (another stress) on top of this stress we can end up doing more harm than good.
The good news is exercise can also influence the other part of our CNS, the parasympathetic branch or rest and digest. The characteristics of this are:
- Decreased breathing and heart rate
- Decreases blood pressure
- Conservation and storage of energy
- Relaxation of muscles
- Stimulates digestion
Basically it's the exact opposite of fight or flight. It's an anabolic state, when your body is in a state of regenerating, rebuilding and repairing. It's plain to see that being in this state more often will promote fitness, health and wellness. While being in a stressed state too often will promote fatigue, muscle loss, digestive issues, increased blood pressure and so on.
Seeing as today's lifestyles add a lot of stress it's important to train the body so that it can switch back to the rest and digest system easily. It's also important to build a resilient cardiovascular system so that your body is better able to cope when stressed.
Building a better cardiovascular system
To become more capable at dealing with stress we can use the characteristics of stress to identify what areas need improving. When stressed, your body is trying to send as much energy around your body so that it can 'fight or flight'. So the first thing we can look at is how good your 'delivery' system is. After all, there's no point in being able to generate loads of energy if it can't get to where it's needed.
Your blood vessels (vascular system) are the pathways your blood takes to deliver energy around the body. Wider pathways are better than narrow ones, more supple ones are better than rigid ones and more vessels are obviously better than less.
In order to develop and improve these pathways we need to train our aerobic system. Note I said train, not use. Using your aerobic system to go for the same walks you've been doing for the past year will not have the desired effect.
Training your aerobic system happens at heart rates between roughly 120bpm and 150bpm. This is moderate intensity exercise and you should be just about able to hold a conversation while doing it.
Activities like walking fast, uphill can be enough for some but generally you'll need something when you can challenge your body a bit harder. Hill walking, weighted walks, cycling, jogging, swimming and circuits can all work as long as your heart rate is between 120bpm and 150 bpm.
Training at this level stimulates the growth of new blood vessels (capillaries) in your muscles, it increases the elasticity of your blood vessels so that they can dilate and carry more blood per heart beat around your body and it even increases the size of one of the chambers of your heart. This is known as improving your cardiac output.
It's worth noting these changes don't just benefit you when you are exercising. They benefit you at all times. Improving blood flow ultimately means more energy gets sent around your body and you become more efficient at removing waste products (like carbon dioxide). This is the foundation of health and wellness. Improving cardiac output means when a stress happens to us we are more capable of dealing with it. Basically, you'll need fewer heart beats to pump blood around the body and so stress will have less of a negative impact on us.
This type of training is also easier to recover from compared to training at higher intensities. This means the overall effect it has on your stress system is low and you will feel energised afterwards and for the following day.
Once you're developing a good base you can then add some exercise at higher intensities. Some! All it takes is a little bit of stimulation. Too much and your system will struggle to recover. Adding more stress like this can lead to fatigue, poor sleep, elevated heart rate, higher blood pressure, muscle loss and so on.
Do you really need to measure your heart rate for this?
That depends, do you want to wing it or know with certainty you're training at the right level for you? Some people can get away with winging it. Certainly when we are younger we've less life stress which means we can handle more from exercise. But as we get older we need to be smarter. Knowing what heart rate you're getting to when doing specific exercises takes out the guess work. And once you know you don't necessarily need to monitor your heart rate every time as long as you can maintain the same pace.
It can be amazing what happens when we train to get fit rather than exercising to just make us tired.