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Is Fatigue A Good Sign of High Intensity Training?

The way we perceive a certain thing, does not always correspond to what is actually taking place in reality. This is true for working out and the way we perceive different types of training. For the past couple months, I’ve been tracking my pulse during workouts where I lift weights; different reps or sets number; different amount of rest in between sets; during yoga or mobility; during swimming, walking, hiking and so forth. It is one thing to know how things work in theory and it is completely different to apply them in practice and feel them work. I noticed some interesting things that I wanted to share with you.

I was about to write this post, when Velin (one of the people who trains in the IFS gym), approached me with the words: “Ines, the Polar tracker does not catch my pulse correctly.” I already know what he was gonna tell me, because I’ve been tracking my workouts with the same tracker. I asked him how he made this conclusion and he was excited to tell me: “Well, see! It shows that my pulse is 117 and I just finished a set of push-ups and it was challenging. In comparison, a little while ago, I was running and it felt easy, yet my pulse was above 150.”

These are observations, who many people have. The strict tracking of my pulse, during different types of physical activities, once again helped me realize how smart the body is and how it reacts in different situations.

Why fatigue is not always a sign that we train with intensity?

What I found out is that very often, the situations when it feels like an exercise is really challenging, our heart rate is actually not that high – even the opposite. Probably you are wondering why. Everything comes down to the strive of the body to survive and be safe. Usually, when an exercise is difficult – for example, we are trying to master a new movement, which requires more coordination, then our perception is that the exercise is difficult and we feel tired. If we track other indicators, like heart rate, we will notice that it is in the lower zones – probably between 90-120. It happens like this, because when we perform such movements, which are new, they are still on the side of a threat for the body. It needs some time to get used to a specific movement, to recalculate how the limbs are spaced out, how much oxygen it needs in order to perform this movement, how much energy the muscles need and so forth. The body needs to feel safe, in order to allow us to do more.

Kinesthetic and visceral sensitivity – what are they and how they matter for our workouts?

Every one of you is familiar with the sensory information, which gives information to the body about the environment and how it needs to react (you are familiar with the five senses). But there are another aspect, and it is the inner senses, which are familiar as kinesthetic senses (the sense about how the body is positioned, how it moves in space and how the limbs are spaced.) The other aspect is the visceral sensitivity, which has to do with the sense of the work of the inner organs – for example the heart, the digestive system, the liver.

These kinesthetic senses, depend on information, which comes from the receptors of the skin (from touch), from balance, and the centers in our ears (as strange as it sounds) and from the proprioception in the joints, muscles and tendons. This is the sensor system, which sends information to the brain and in return the brain decides to allow a certain movements, to be performed from the muscles, with a certain speed and intensity.

How the speed of the movement matters?

It is an interesting fact, that even when you perform the same movement, but with different speed, different parts of the brain activate and the response from the body is different.(Supertraining,  Yuri Verkshoshansky)

For example, isometric (for example, plank) and dynamic movements (jumping lunges) activate different parts of the brain, because isometric movements, increase blood pressure, but do not increase blood circulation. While dynamic exercises, require the generation of oxygen, which is being met with increased blood circulation. This has its take on the heart rate and even though in both cases it will increase, the level of intensity is different.

For example, for some time, I’ve been keen on the straddle press. When I practice this movement, just 3-4 reps are enough, so I feel pretty tired, and my heart rate doesn’t increase much. Being tired is a result of the fact that the nervous system sends signals to the muscles, as well as the whole body, to make us stop doing what is “threatening us”. Exercises from this type are more challenging when it comes to coordination.

Let’s take the example with Velin – running, even though it is not an easy physical activity, is something way more natural for the body, then doing push-ups – not everybody can do push-ups, but everybody can run (with his own style). Running is not registered by the nervous system as something “unfamiliar” and this allows us to keep up the pace, and perform this physical activity for a bit longer. In return, this has to do with the need of more energy, increased oxygen requirement and a higher heart rate.

Two types of fatigue and how to differ them?

Besides that, you can differ two types of fatigue – central and periphery. Central fatigue has to do with the nervous system. With exercises, that are new or close to our maximum, central fatigue is the first thing we feel. Probably, all of you can think about situations, when you feel like you can keep going, yet you are exhausted and your body blocks.  It happens like that, because in reality your muscles are not tired, but your nervous system is and it gives you a signal to stop. That is why, developing resistance to this fatigue, depends on the workouts being with enough frequency and intensity, so we can train our nervous system to deal with this type of activities. This is one of the reasons, why more experienced trainees, can endure higher intensity for longer periods of time – their nervous system is trained enough and everything comes up to mobilizing the periphery nervous system, which has to do with the fatigue that is felt in your muscles.

What is the link between the perception of fatigue, the intensity of the workouts and the weight loss process?

Very often, when the trainees perform a certain exercise, which make them tired, they falsely make the conclusion that they’ve trained with enough intensity and that this is enough. Then, they go back home and eat like they had an intensive workout. Usually, a couple weeks later, they feel discouraged that they do not lose weight and that they do not have the results they want. They say how they try everything and how they make enough effort, yet they do not have results and some of them even quit. In reality, they just do not realize how the body functions and that just feeling tired is not enough as an indication for a good workout. Sometimes, fatigue is just a mean of the nervous system to make us stop doing what takes the body out of its safe zone.

It is really important to know how different types of physical activity, transfer in different qualities and how to structure our workouts in a way that helps us improve, by mastering new movements and to become stronger, faster, more athletic, while challenging other systems in the body and to achieve the desired fat loss.

Of course, behind everything with the heart rate, the level of intensity and the systems, which the body predominantly uses with different levels of intensity, there is a lot of science, which you do not need to know, in order to make a good workout.

Tracking your heart rate, helps a lot in order to know which zone you work into and what happens in your body. Just fatigue as an indication for a good workout is not enough. This doesn’t mean that if you feel tired, you don’t have to stop. But you need to learn to listen to your body and know what type of fatigue is an indication to stop and what type of fatigue can be overcome, so you can keep training.

As a whole, you know that even treadmills, have intensity zones, which show you what you work for in different zones. I won’t overburden you with the information about different energy systems, but I will give you a guiding point about the intensity you achieve with different types of training. You need to keep in mind, that the time you train, doesn’t have to do with how much you train, but what is the maximum amount of time, which you can sustain a certain intensity – i.e. it is one thing to run 60 seconds at a maximum speed and then feel that you can’t go anymore, and it is a whole different thing to run for 60 seconds with moderate tempo and stop, just because 60 seconds passed, and not because you have reached your limit. For me, this is the key to quality training – to make the difference between the amounts of time we train and the quantity of the work we have done during this time. Workouts do not need to be for time, but for quality.

In the past, my main physical activity used to be lifting weights. I trained mainly with reps between 5-8, in sets between 3-5, depending on the exercise and the intensity. Then, I decided that I want to try more sports, because I love learning new skills and training my body in different ways. Every sport and type of physical activity has different requirements on the body. By tracking my heart rate and how my body reacts to different activities, I connected better with my body and now I am better aware of what and when my body needs it. It is really interesting how when you track different indicators, you learn to “read” different types of fatigue. After a couple months of experimenting, I can now guess my heart rate, even without tracking it, which gives me a pretty good idea about what is the intensity of the workout and what I work for. It is important to understand, that just because you have some exercises in your workout, with certain sets and weights, doesn’t mean that the intensity you achieve will match the intensity that someone else will achieve with the same program. For example, if you really know your body and if you perform the exercise properly and with enough intensity, you can have 4 exercises, each performed in 3-4 sets, in the time frame of 30 minutes and achieve a better loading than another person who will perform the same workout in the time frame of 60 minutes.

Besides that, the skill to track this indicators and to know how your body reacts with different loads, gives you an opportunity to train more often, without overtraining. What do I mean?

training-zone
An example of my last hike.

For example, now I train with weights 2-3 times a week; one of the days I swim; 1 day I do yoga and one of the days I do some intervals (some kind of a short workout – sprints or some dynamic exercises combined in intervals) and 1-2 days I rest. On my rest days, I walk every day and I do some mobility or sun salutations. This allows me to be active, all the time, but some days I take an hour to train, some days it is just 30 minutes and other days I train a little bit more than an hour – depends on exactly what I choose to do.

With different activities, I achieve different levels of intensity and I work in a different zone – for example, when I do yoga, my heart rate is usually in the first zone, rarely in the second zone. Besides that, after the workouts I feel fatigue, but the kind of central fatigue I mentioned – it is just that the movements I train are more complicated when it comes to coordination and often times my muscles can endure longer, but my nervous system sends a signal that I can’t. The more I practice, the more I get over this threshold of fatigue and things change.

With swimming, depending on how I structure my workout, sometimes I work in the second zone and in the third zone. Other times I have shorter and more intensive workouts and I train mainly in the third and fourth zones.

With intervals or short circuit training, my heart rate is usually in the third, fourth and sometimes in the fifth zone.

The same is true for lifting weights – depending on how much reps I do, what is the weight I work with and what is the amount of rest in between sets, I usually train in the third, fourth and sometimes fifth zone.

Besides that, even when I do body weight exercises, but in dynamic way (for example jumping Bulgarian squats, jumping lunges and so forth), my heart rate is once again in the zones with higher intensity, because as I wrote here, these type of exercises, even with lower intensity (as a percentage from the maximum), transfers in more work.

In this way, often times, yoga, mobility and sometimes swimming (if it is not an intense workout), help me work in lower zones, where my heart rate is not that high, yet I have a benefit – I am active, the increased heart rate and the type of activity increase the circulation of blood, the recovery of the tissues and in reality it makes the workout a recovery tool for the rest of the workouts. In the same time, I still progress and I develop other skills – as it is with yoga and mobility. All of this shapes me as an athlete and it helps me master other skills.

And last but not least, tracking all of this, helps me observe how my body reacts when it comes to my appetite and the hunger I have after different physical activities. It is one thing to think that just because a certain workout makes you tired, this means you have worked with high intensity and then eat a double food portion because you think you need recovery. It is a whole different thing to be aware that just because the workout included movements, which develop your coordination, balance and so forth and this led to central fatigue, this doesn’t mean that you spent so much energy and doesn’t mean you need a double portion. It is really important to not fool yourself and to know how your body reacts to different levels of intensity and types of physical activities.

 

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