designing heartbeat metrics to live longer
In this post I will be providing one of my most important recent insights regarding health and longevity and it contains very powerful information I gained about training and workout routine in the last 5-10 years. It even goes beyond some crucial nutrition changes, sleep routines or stress management.
What I want to share, and also later dive into, is a very simplistic and basic statement: "One of the most important but also most overlooked type of activity is the Zone 2 cardiovascular training."
If it is true, that everyone has only a predetermined number of heartbeats, I am sure I have already spent more than half of mine. Heartbeat-wise I am a decade older than my chronological or biological age. I used to do, since recently, tones of all-out sprints, fartlek types of exercise, HIIT trainings, Tabata routines etc. My kind of flaw can be described with one sentence: “The average runner runs too fast on their slow days and too slow on their fast days.” I thought I need to push hard to build endurance. I believed I needed to feel exhausted or stressed at the end of training, the all-or-nothing mentality.
What I neglected completely is the old lazy kind of Zone 2 cardio activity. The greatest advice from my latest coaching mentor was: "Be lazy!". But funny thing is, the hardest thing when you want something is to go slow and easy, to be lazy.
What is it all about? Zone 2 training:
- increases the number of mitochondria and their efficiency
why carrying for one's mitochondrial health is paramount for longevity , health and vitality
one is only as productive and healthy as theirs mitochondria are
- increases “metabolic flexibility” and improves insulin resistance
with metabolic inflexibility one can not use fat as a fuel and in spite dieting will have a hard time loosing fat stores.
- lowers resting heart rate and decreases the blood pressure
- improves resilience and endurance
- improves Zone 4,5 function/performance
AND - improves longevity
How does all of this happen? With your physiology. We need to take into account what is happening inside your cells and how does that drive your physiology and physique. In zone 2 very potent biochemical processes with a big impact on metabolism and energy systems of the body are unfolding, the base for all the powerhouse is being built. What used to be considered as the most efficient fat burning mode, has turned out to be way more than that: in zone 2 the body is not only becoming leaner, but also younger and more efficient, performing on higher level. The major switch in fighting the leading killer diseases and lowering the risk factors for being afflicted by them, is to improve energy efficiency, that is to gain metabolic flexibility and fight off the insulin resistance. Most of the chronic diseases have a common root cause – poor metabolic health due to poor mitochondrial function. Scientists are now finding evidence of mitochondrial dysfunction nearly 5-10 years before those changes will manifest as a disease. Building the foundations of mitochondrial health, cardiovascular system, immune system and others is not only improving the performance but also minimizing the risk of developing cancer, Alzheimer's, CVD and thus affecting the longevity scale.
What is the zone 2 training?
It is any kind of physical activity done within the definable terms of biomarker lactate or heart rate. Since heart rate is also influenced by other factors, as rest level and recovery, hydration, body temperature, lactate measurements are usually more accurate. They also provide more information what is going on inside the cell and are presenting the biochemical processes in longer time frames than does the heart rate. For example, if we power up the training, the heart rate will go up faster then lactate, but will also drop faster after the effort is lowered. Lactate needs at least 10, 15 minutes up to one hour to get cleared out of the system, depending how trained and lactate efficient one is. Trained individuals can re-use the lactate as a fuel, which makes them even more efficient.
TO simplify, Zone 2 is one of five heart rate zones you can enter within training, being walking, running, swimming, cycling, rowing or else. It usually refers to intensities where your heart rate is 60-70% of your maximum, but, as said, is even more precisely defined with lactate thresholds.
Methods to define Zone 2:
One of the most used methods though is by calculating the maximum heart rate by subtracting the age from 220. It is the most imprecise method and of low value. It implies that two people of the same age, regardless of every other body/ physical/ performance metrics, have the same max. HR. It is the same as saying two people of the same height and weight can eat the same number of calories to reach the same health/ body composition goals.
Better method is by knowing the maximum HR and your resting HR, the difference being the value called “heart rate reserve”. 70% of the heart rate reserve added to your resting heart rate is your aerobic threshold:
0.7*(HR max — HR at rest) + HR at rest. In my case, 0.7*(183–47)+48 = 142 beats per minute
different kind of gadgets provide the possibility for automatic and individualized calculations and monitoring of heart rate zones
There is also one more “at-home” method, but I would not rely on that one without many years of heart rate monitoring and awareness of body sensations, that is perceived effort or breathing pace and breathing pattern. One who is not familiar with long term self-observation will most probably error in both directions with the estimation of zone 2 training relying on body sensations. Most often they will find themself in zone 3, since for majority it is harder to keep the pace down to zone 2. Running or cycling up hill can easily get your HR above 140-150 while you still maintain the conversation or breathing pace.
The most precise method though is to do testing and measurements in a laboratory.
Zone 2 training is done as a base training as it is completely aerobic. All elite athletes spend majority of their active training in zone 1 or 2 (75-80%). Only 20% is spent in higher modes, building also the anaerobic capacities of the body – VO2 max. This is what is called a polarized training.
Why is it so important to stay within the zone 2?
While exercising in Zones 1 and 2 improves mitochondrial number, function, flexibility, efficiency, and fitness, exercising in zone 3 and above does not improve the aerobic (mitochondrial) health nearly as well. Training under the so-called zone 4 ceiling is not going to improve your zone 2 ceiling. Physiologically speaking, we are dealing with two very different energy systems. One occurs inside the mitochondria and the other inside the cytoplasm of the cell. In other words, training in Zone 2 improves all zones above it (3-5). Training in higher zones does not improve lower zone fitness.
Zone 2 is powered by fat oxidation. It is the most efficient way to burn the fat stores. Going into zone 1 lowers the efficiency of fat burning. On the other hand, once you cross the ceiling of zone 2 into zone 3, you are starting to switch to glycolysis, the catabolism of glucose. The reason for that is, the fat is no longer providing enough energy, and glucose take over the field of being the main energy source. The side effect of this is the lactate rise. Lactate prevents the fat oxidation, so even after switching back to zone 2, lactate is now the limiting factor of fat utilization. Staying in zone 2 is therefore crucial. But the story does not end here. Well-trained athletes can “shuttle” that lactate back into the mitochondria to use as fuel. So, there is a positive reinforcing loop, zone 2 promotes the shuttle capacity of lactate breakdown.
The transition point from zone 2 into zone 3 is noticed by lactate rise and is therefore also named first lactic acid threshold or LT1. Anything below this point is considered aerobic. The ceiling of zone 2 is the lactic acid threshold 2 (LT2) and is the point where the training goes anaerobic.
Therefore, you do not want to leave zone 2. The benefits of zone 2 training come from staying in zone 2 the entire time. Hopefully for a 60–90-minute workout, 45 minutes being the minimum. Zone 2 is hard because most people find it very challenging to stay at a slow pace for a long time. It feels like doing nothing. While everyone else is pushing harder, you are going low. Not doing is essentially harder than doing. It feels boring. But it builds not only stamina but also power over own mindset, perseverance and patience with oneself. Not only is it building endurance in training but also of the mind.
The reason why you can maintain low heart rate efforts for a long time is that we have an infinite source of energy available from our fat stores. The same is not true about our glycogen stores.
Nevertheless, even if the pace and effort remain constant, in long training sessions the heart rate starts to drift away into zone 2. As the training improves, so will the starting time of the drift occur later. With any drift out of the zone 2 adjust the effort to maintain the same heart rate.
But, if you still want to rank it up, tack some intervals or add some sprints or hills to a long workout, do it at the end of your zone 2 training. Try to ride 75-80 minutes in zone 2 and add high intensity at the end of the workout. That way you are also exercising at your lactic acid threshold, and perhaps your VO2 max. It is a way to perform both types of trainings – energy systems in one shot instead of doing them on a separate day. Our VO2 max also contributes to our health, but perhaps not as much as having a solid aerobic base which can only be built with many months of mostly Zone 2 training.
zone 2 Airbike workout
zone 2 treadmill workout 10% incline walk
To gain improvements in zone 2 aerobic base one needs to pull out at least 3 sessions per week. For maintenance 2 is enough. The results can be seen only in several months, contrary to anaerobic measures, which can be improved in weeks of regular training.
Finally, fasted zone 2 training, especially in the context of restricting carbohydrates, may help to stimulate stronger signals for adaptation specifically in terms of mitochondrial biogenesis. If one is time-poor and is looking to maximize all potential gains in fitness from this part of their training program, fasting or training with low carbohydrate availability may serve this goal well.
Everyone has enough time, energy, resources and skills, if applying smart metrics and tools about how to do it, if knowing why to do it, and deciding where and when to do it. Psychologically speaking, what’s nice about Zone 2 training is that it’s relatively relaxing, low stress day-to-day (easy to recover quickly from) and can serve as a productive break. Also comparing to highly structured, higher intensity training, it does not require a great deal of mental focus and pain tolerance. If it gets hard, you are most probably not doing it right.
I must admit for me it feels so effortless and boring I bring my work or fun into the routine. During the hour or so on the treadmill or bike I read and respond to emails, listen to audiobooks, write posts, read lecutres etc. Sometimes though, I just daydream, focus on breathing or mind-drift into deep thinking. That is why I honestly believe with right approach everyone can find time to do it. Combining with some other activities, this otherwise mundane workout, can not only save some time but also become fun and relaxing.
Since I introduced it back into my routine, my average blood glucose levels dropped for about 1-1,5 mmol/L, my resting heart rate decreased, my HRV and sleep improved, and my overall health-wellness improved.
I dedicate this post to my little sister. I hope all your answers were answered. Let another race begin :).
Med Sci Sports Exerc. 2022 Jun 1;54(6):1028-1031. doi: 10.1249/MSS.0000000000002871. Epub 2022 Feb 8. Polarized Training Is Optimal for Endurance Athletes Carl Foster, Arturo Casado, Jonathan Esteve-Lanao, Thomas Haugen, Stephen Seiler
https://podcasts.apple.com/si/podcast/trainingpeaks-coachcast/id1435395422?i=1000596507786
Healthcare (Basel). 2021 Jul 6;9(7):851. doi: 10.3390/healthcare9070851. The Effect of Polarized Training on the Athletic Performance of Male and Female Cross-Country Skiers during the General Preparation Period. Tae Ho Kim, Joung Kyue Han, Ji Young Lee, Yong Chul Choi