I have been talking about the 80/20 principle in endurance training to those interested in increasing their cardiovascular fitness. As It seems like an easy enough approach to adhere to. With evidence of success from studies done on elite endurance athletes and hobbyists alike.

The gist of it is, to spend around 80% of training time in lower HR zones and 20% of the time in higher HR zones. One way to easily know what is low enough, is only do nasal breathing during the workout, without it being too difficult. Or to be able to carry out a conversation, with it being noticeable that you are working out.

While often talking about it, I realized that I had not checked how are my intensity zone distributions looked over time.

I have data with polar all the way to 2020. With a bit of 2019. So there should be plenty to get a decent overview.

all-months-of-data

Note on my goals

Working on the fitness of my heart, my cardiovascular fitness, is one of my focus areas, but not the only one. I also aim to keep on a decent amount of muscle mass, in addition to being strong and powerful.

That said, I still want my cardio training to be efficient. At this point in time my cardio training included cycling for commute, low effort jogs and High Intensity Intervals, 4 times 4 min with 4 min rest protocol. But I had never actually looked, how the percentages spread out over the weeks and months.

TL;DR

Do I adhere to the 80/20 principle in endurance training? By the looks of it, no I don’t.

About 1-2% in zone 5 and with zones 4-5 summed up, still well under 20%, with zones defined by polar. So looking at the data, I might consider doing some more intense trainings from the heart rate perspective. Worth experimenting.

If I were to only account for specific cardio trainings, the numbers would be different. Not sure if all trainings can be considered equal from the effects for cardiovascular fitness, when observed from the HR perspective.

Keep in mind that percentage of time in different zones is not the whole story. Total time spent training is also important. Just spending 1h a week training does not yield the same results as spending 10h a week training. If I would want to focus on my cardiovascular fitness, I could also increase cardio training time in total. If one wants maximum training benefit from as little time as possible, then training would likely look different.

Yearly view - All sports

For this blog post I only looked at the years I had data for each month. 2020-2023, a total of 4 years.

2020-2023-distribution

While there can slightly varying definitions for what is High Intensity. Today lets consider zones 4 and 5 to be High Intensity.

Then my % of time spent in high intensity zones has decreased over the years.

2020 - 15%
2021 - 11%
2022 - 10%
2023 - 9%

Although 2022 had the highest number of hours in zone 5.

Lets also look at the total training hours logged for these years.

2020-2023-training-hrs

2020 - 516h
2021 - 494h
2022 - 411h
2023 - 466h

Here 2020 comes out in the top. However both 2022 and 2023 I spent 2 months in south america, with quite a bit of hiking that I did not log with Polar. If we account for those then I believe the percentage of high intensity would actually be lower or very similar.

Zooming into an outlier

When I was looking into specific months, then May of 2022 sticked out from the rest. With 1h48min in zone 5. :O what happened there? That is one month that accounts for 1/3rd of the whole years time in zone 5.

may-2022

I opened the calendar view and it became more evident what was happening.

That month I had weekly judo sessions, with lots of randori

A judo practice with many randori

While in most of these sessions there were small dropouts in the HR data. These did not affect the overall percentages too much.

Here is one example from a session with good coverage in HR data, with some dropouts where the signal got lost.

good-coverage-hr

By the looks of it, there was a warmup session, and a total of 10 bouts where my HR was consistently in zone 5.

judo-practice-with-overlay

Just thinking about the intensity and the fact that I actually did 10 makes me be impressed about myself. As this is way more intense than the 4x4 intervals I do now.

Also by the looks of it the rest period was about 2 minutes at best. And the work perioud about 3 min. So 10x of 3 min work 2 min rest. Pheww, yeah, that was something different.

Funny enough, during the past days I was just chatting with a judoka I used to train with. Talking about getting back into regular judo, perhaps even competing. Maybe it all makes sense and I should get back to regular randori trainings in order to get my high intensity cardio work in.