Interview

 (RP) We now understand that it is an important number. So how is VO2Max measured?

(Kojima) It is measured by an optical sensor installed in a smartwatch for sports. For example, since the release of body composition analyzers, everyone can now measure "body fat percentage" at home. Then, the numbers that until then could only be measured in hospitals or places with specialized equipment became familiar, and the public's diet knowledge and health awareness changed, didn't it?

(RP) It was a major change that shifted the standard for weight loss from "body weight" to "body fat percentage. "

(Kojima) Similarly, as a result of the "visualization" of cardiopulmonary function with wearable IT devices, one important number that has become familiar is VO2Max. Now it is also possible to measure blood oxygen saturation level (SpO2), and the Apple watch has also been equipped with this measurement function since the autumun of 2020.

(RP) It's such a convenient time to be able to do such things with a familiar mobile device.

(Kojima) Although we do not actually measure the amount of oxygen in the breath by running on a treadmill (running machine) wearing a mask, there is a certain correlation between age, weight, running speed, distance, and heart rate. So when a person runs a certain distance wearing a smartwatch, their VO2Max is measured. A typical brand is GARMIN from the U.S., and SUUNTO from Finland is also popular. By the way, I use Casio's G-SQUAD.

(RP) If big data and healthcare are connected in such a way, various information will be visualized, which will bring many benefits.

(Kojima) Thanks to IT, runners can now obtain objective data on their running ability and physical fitness, and VO2Max is expanding as an indicator for considering practice menus and training volume. There are other indicators that measure overall running ability, such as "AT value (anaerobic work threshold)" and "running economy," but VO2Max and heart rate are the core important figures. And I am glad that these can now be easily measured. When I was in junior high school, we all used to measure our heart rate by putting our hands on our necks and wrists after running during track practice, but there were many errors and "imagination".

(RP) So it means that runners don't just run, but they enjoy running while dealing with various numbers in addition to their times.

(Kojima) I suppose not all runners are like that, but it is a big change to be able to easily check VO2Max, which has a deep relationship with one's performance and record.

(RP) It is significant that not only runners but also non-runners can now use blood flow and heart rate as an indicator of daily health management, rather than just as a number to be learned at a medical checkup or hospital visit when we become ill.

(Kojima)That's exactly right. Thanks to the smartwatch, factors that until now had only been abstract images of "stamina" and "physical strength," and were only vaguely perceived as being present or absent, can now be managed and improved numerically.

(RP) Then, runners, who are more interested in strengthening their cardiopulmonary functions than anyone else, will be increasingly motivated by the visualization of VO2Max.

(Kojima) While the specific issues and interests differ from runner to runner, the desire to improve VO2Max is, of course, held by many runners. Some runners show each other their VO2Max display screens and internal body age on Facebook and Instagram, and runners are generally 10 to 20 years younger than the average of their non-sporting people in terms of such figures. While "vascular age" cannot yet be measured, runners are probably younger than the generational average.

(RP) For example, specifically, what level of VO2Max is high and what level needs to be improved?

(Kojima) According to "Reference Values of Maximal Oxygen Intake by Gender and Age for Health Promotion" included in "Exercise Standards for Health Promotion" (Ministry of Health, Labor and Welfare, 2006), the reference values of VO2Max by generation and age are 40 ml for men and 33 ml for women in their 20s, 38 ml for men and 32 ml for women in their 30s In their 40s, men are 37 ml and women are 31 ml; in their 50s, men are 34 ml and women are 29 ml; and in their 60s, men are 33 ml and women are 28 ml.

(RP) Comparing people in their 20s and 60s, there is a drop of almost 20% for both men and women. It makes sense that as we get old, our weight increases and our muscle strength decreases, making daily life more difficult. People who are obese or inactive will naturally be lower than the standard, so their work and quality of life will also decline.

(Kojima) Although there may be differences in the way VO2Max is felt, to introduce a familiar feeling, the higher the value, the less likely you are to feel tired or short of breath. And if the value is low, you may feel "short of breath when going up several floors of stairs in a building or station," or "tired and sweaty when running for a bus stop. "

(RP) That is easy to understand. By the way, what is your VO2Max?

(Kojima) I go up and down between 58 ml and 62 ml depending on the quality of my running, which is about 1.5 times the standard value for men in their 20s. My record in half marathon is about 84 minutes and 10 km is about 37 minutes, so I am in the upper end of the VO2Max range for men in their 40s. Some Olympic athletes, professional runners, and experienced runners of the Hakone Ekiden (relay marathon race) exceed 80 ml. These people do not get tired from running the distance of several train stations or running up 10 to 20 flights of stairs in a building. Even if they get short of breath, their heart rate quickly returns to that of a resting heart rate, and this level of exercise does not leave them tired the next day.

(RP) If we are an inactive member of society, even just going up a few stairs will tire you out, so it makes a big difference. When we consider that the difference affects our entire life, I get the feeling that improving VO2Max is not just an issue for runners.

(Kojima) If weight and body fat percentage are "car weight," VO2Max can be regarded as the air volume displacement. If the engine of a large car is weak and its performance is low, what will happen? Humans are the same way. Since muscle strength is "engine performance," a person with weak muscle strength is practically the same as an obese person, and is not utilizing oxygen.

Official ambassador and exclusive contract runner of Blut Runners Q

Mr. Naotaka Kojima（Instagram @naotaka_kojima）

■Profile

Born in Fukuoka Prefecture in 1975, Mr. Naotaka Kojima passed the overseas work exam while a student at Seinan Gakuin University in 1995 and joined a trading company in Malaysia. After returning to Japan, he worked as a business writer and sales planner in a business magazine publishing company in Fukuoka City.

In 2001, he started his own business as an editor and translator, and after working in the business education field, he started his trading business in 2009.

After serving as a director at a medium-sized general contractor in Malaysia, a food trading company in Serbia, and a resource development investment fund in Hong Kong, he has been the managing director of J-Tech Transfer and Trading (export and international technology transfer business) since 2014. He is currently working hard to develop overseas sales channels for small companies in Kyushu and western Japan.

■Running Record

March 2021 "Hitoyoshi Marathon" (half marathon category) 7th/402 runners (1:27:52)

1987 Fukuoka Prefecture Elementary School Athletic Game (Heiwadai Athletic Field), 800m, 8th place/prefecture

1988 Chikushi District Marathon (5km), champion (18:10)

1990 "Tobiume National Athletic Game" torch runner (16:34/5km) *selected from junior high school track and field clubs in the prefecture