[We asked an expert] How to walk using the PRO TREK Smart WSD-F21HR, which can measure your heart rate, to help you improve your endurance without fatigue?

Many people know that heart rate is said to be useful for managing people's physical condition and for athletes' training. Simply put, heart rate is the number of times the heart beats per minute. The average adult's resting heart rate is said to be about 60 to 80 beats per minute. Naturally, the rate at which heart rate increases varies depending on the level of exercise

Professor Maekawa Yoichi (Department of Physical Education, International Budo University) has a track record of placing 6th in the Lake Saroma 100km Ultra Marathon (1999) and completing the Mount Fuji Climbing Race. He is also well versed in heart rate research, having even measured and verified his own heart rate. While at Tsukuba University, he ran the 5th leg of the Hakone Ekiden. He gives lectures around the country, instructing a wide range of people, from beginners to advanced runners, from junior athletes to masters, and also provides instruction in everything from walking to jogging in health promotion programs. His major publications include "The Marathon Textbook You Never Knew."

This time, we spoke with Professor Yoichi Maekawa of the Department of Physical Education at International Budo University, a specialist in training science, about whether it's possible to climb mountains without getting tired or to improve your physical abilities using CASIO's PRO TREK Smart WSD-F21HR (hereinafter referred to as F21HR), an outdoor smartwatch that can measure heart rate, and how to put this into practice.We then actually used the F21HR to climb mountains while controlling our heart rate, and here is our report on the results

table of contents

• Why does an increased heart rate make you tired?
• The type of exercise you do will change depending on your heart rate zone, which indicates the intensity of your exercise
• The key to hiking without getting tired is "burning fat while walking"
• When climbing mountains, be aware of fluctuations in your heart rate on steep slopes
• To improve your endurance, climb in heart rate zones 3-4
• Maximum oxygen intake is also important for a body that doesn't tire easily
• I actually tried climbing a mountain with my heart rate in mind, with the aim of not getting tired and building endurance
• summary

Why does an increased heart rate make you tired?

For example, let's say there is a 5km stretch of flat paved road. Whether the same person runs this distance at full speed or walks slowly over a long period of time, the distance traveled is the same, so the energy consumed will be roughly the same.

However, the person who ran at full speed felt more tired after the run. Why did they feel differently tired even though they burned the same number of calories? The difference is that one person burned 250 calories in 20 minutes, while the other burned 250 calories over an hour. This is where heart rate comes into play

The former is running with a fairly high heart rate, while the latter is walking without increasing the heart rate much. The crucial difference between the two when they get tired is the "energy source used ." The former, running at full speed, uses glycogen as energy, while the latter primarily uses fat as energy. If you continue to consume glycogen, you will become exhausted and unable to move. As long as you are burning fat, you can continue exercising. In other words, the high heart rate during exercise is a function of the energy source used, and this greatly affects how tired you feel and the effects of exercise .

Incidentally, when it comes to burning body fat, there's actually not much difference between the two. That's because walking is aerobic exercise, so fat is used while walking, but when running at full speed, fat is not used as much while running, but fat is burned during the fatigue recovery process after running. This is the "afterburning" process, where fat is burned after exercise. In terms of burning fat, even though the way you get tired is different, the overall effect is the same

Although he is not an expert in mountain climbing, Professor Yoichi Maekawa is well versed in the field of heart rate, having even measured and verified his own heart rate. He is also a senior coach certified by the Japan Sport Association and the Japan Association of Athletics Federations

The type of exercise you do will change depending on your heart rate zone, which indicates the intensity of your exercise

A high (low) heart rate is not an absolute number, but rather a relative value for each person. In order to use heart rate to target exercise, it is important to first know what percentage of your maximum heart rate you exercised at. Although there are individual differences, your maximum heart rate (bpm) can be calculated by subtracting your actual age from 220. For this reason, the upper limit of your heart rate generally decreases with age

If you're just trying to improve your health, it's enough to keep moving without getting out of breath. If you're trying to burn fat, you need to exercise at a slightly higher level. Anything beyond that is training territory. If your goal is to improve your endurance, you need to push yourself further. However, it's not enough to just get your heart rate close to 100%. If your heart rate is over 90% of your maximum, the exercise will be more effective at improving anaerobic endurance rather than aerobic endurance

• Zone 5: 90-100%...Improves anaerobic endurance
• Zone 4: 80-90%...Improves speed endurance
• Zone 3: 70-80%...Improved aerobic endurance
• Zone 2: 60-70%...fat burning
• Zone 1: 50-60% - Warm-up, cool-down, walking

*For more information on heart rate zones, the PRO TREK Smart website . % indicates the percentage of maximum heart rate.

With the WSD-F21HR, you can check your heart rate zone along with your heart rate while you're moving. (Note: To do this, you'll need to set your maximum heart rate and resting heart rate initially.)

The key to hiking without getting tired is "burning fat while walking"

If your heart rate is below 80% of your maximum (zone 3 or below), you are basically getting enough oxygen, and your body is converting fat into energy. If it's between 60% and 70% (zone 2), you're definitely burning fat . If you're using fat as energy, fatigue won't accumulate. However, if you don't exercise much on a regular basis, lactic acid may be produced (leading to muscle fatigue) even in that range. Also, the way lactic acid is produced differs depending on whether or not you can use fat (as energy).

If you can keep your heart rate below 70% of your maximum, you can convert fat into energy and climb without getting tired

When climbing mountains, be aware of fluctuations in your heart rate on steep slopes

Lactic acid is produced temporarily when you sprint at the end of a marathon, but even in a marathon, if you keep your pace constant and keep it down, lactic acid generally doesn't build up. However, when climbing a mountain, you push hard to lift your body, which uses your muscles . This damages the muscles, so lactic acid may be produced. If lactic acid is produced, your heart rate is increasing. In other words, you are in an oxygen deficiency state. There is not enough oxygen for the exercise intensity. If your heart rate increases and you are not receiving the necessary amount of oxygen, lactic acid will build up and fatigue will build up.

Additionally, if you're just walking up a gentle slope, your heart rate is unlikely to suddenly rise. However, this is not the case when climbing a mountain. Naturally, you'll encounter more diverse terrain than in a marathon, with slopes varying in both direction, climbing over rocky areas, and varying ups and downs, so your heart rate is more likely to fluctuate. Excessive fluctuations in your heart rate can also be a negative factor in terms of fatigue

If you want to climb without getting tired, it should be easier to walk over time and keep your heart rate from rising and falling as much as possible . Your body can't handle a constantly rising heart rate, so even if it rises for a moment, let it drop again and return to a steady state. If you can maintain a steady state for a long time, I think you'll be able to climb without too much difficulty. Keeping your heart rate as low as possible will ultimately reduce fatigue. In that sense, if you feel short of breath, check your heart rate, and if it's high, slow down your climbing pace a little or take a break. By taking measures like this, I think anyone can move forward without straining themselves.

Because mountains have many ups and downs, your heart rate tends to fluctuate greatly

To improve your endurance, climb in heart rate zones 3-4

For example, if a beginner marathon runner's goal is to complete the entire race, there is no need for strenuous training. They would be instructed to slowly increase the distance they run without increasing their heart rate. However, if they want to improve their finishing time, they will need to get used to running at a faster pace. This means they will need to train to increase their heart rate and improve their endurance. When it comes to building endurance, it is effective to exercise at 70-90% of your maximum heart rate, in a heart rate zone around 3 or 4. The important thing to remember is that pushing yourself to the limit does not necessarily mean you will have better endurance.

As you continue training, your heart rate will become less likely to rise, even with the same exercise load. This means you can increase your speed. Also, even if a training person's heart rate suddenly increases, it will drop back down after about a minute of rest, but someone who is not exercising will remain out of breath and their heart rate will not drop easily

If you walk at 70-80% of your maximum heart rate, your heart rate will gradually increase less even with the same exercise, and you will develop endurance

Maximum oxygen intake is also important for a body that doesn't tire easily

Another indicator of endurance is that people who can walk fast even when climbing a mountain with lots of ups and downs likely have a high maximal oxygen uptake (VO2 max (V with a dot)). Maximum oxygen uptake is the maximum amount of oxygen the body can take in. If maximum oxygen uptake increases, the body is less likely to experience oxygen deficiency, meaning you are less likely to get tired and you will be able to tolerate more intense exercise. For the same exercise, your stamina will last longer, and for the same distance, your speed will increase. To improve maximum oxygen uptake, it is effective to consciously raise and lower your heart rate . Alternating periods of exertion and rest will stimulate oxygen uptake rather than continuing to apply a constant load. This is what is known as "interval training."

It's impossible to climb a mountain above your level in one go. You need to take it step by step so that oxygen can be delivered to your entire body. This is why cardiopulmonary function, such as the heart and lungs, is important. It's better to climb the mountain slowly and for long periods of time so that oxygen can be delivered to the extremities of your body. The higher the mountain you go, the more important your maximum oxygen intake becomes. How much oxygen can you utilize in a thin atmosphere? The higher you climb, the more important it becomes

An effective way to improve your maximum oxygen intake is to increase your heart rate

Next page: Trying out heart rate mountain climbing with the WSD-F21HR