Monitoring or data collection such as heart rate and body composition has become a trend, and various gadgets are available in the market. It is very useful since you get to quantify your progress. For heartrate monitors, you can adjust your intensity level according to your heartrate, HRV (heartrate variability), sleep and so forth. However, majority of population seems not able to maximize the benefit of data tracking and not sure what devices to use for accuracy of the data.
Before going into devices, let’s discuss why tracking heart rate and body composition is useful and what are some factors that have impact on it.
Heartrate
Heartrate is monitoring how many time the heart is beating within one minute. While resting and laying down you may see your heartrate being anywhere between 60-100 beat per minute (bpm). When aerobic capacity and recovery rate is high, you may also see the resting heartrate as low as 40s.
When I see heartrate numbers, I think of how much heart is working to send the blood throughout the body. For individual who has resting heartrate of 70-100bpm, means their heart must work at that rate to pump the blood to their entire body. For individual who has lower resting heartrate (40-60bpm), their heart is conditioned to provide blood with less work. Of course, just by looking at heartrate cannot paint the full picture; however, you can make pretty good, educated guess on what those numbers mean.
Heartrate can be influenced by aerobic capacity (VO2max), stress, sleep, caffeine, illness, alcohol, frequency and intensity of training and so on. Especially with resting heartrate, you can tell about your condition. When under heavy stress the resting heartrate can be higher than normal and because of that it may affect your training sessions.
Body Composition
Body composition refers to your height, weight, body fat, muscle mass, visceral fat and so forth. By monitoring your body composition, you can observe how the body is transforming according to your nutrition, exercise and recovery. It is not absolute, however, looking at these numbers may help you plan your training sessions based on what goal you are wanting to accomplish.
Heart Rate and Devices
Originally, we’ve monitored heartrate during exercise by checking the pulse by using wrist or neck pulse. Now with technology we can use watch, phone, straps to monitor heartrate throughout the day and while exercising.
The most accurate device or close to EKG level of heartrate monitoring device is heartrate chest strap. Although it is somewhat uncomfortable at first, but it picks up the heartrate signal (R wave) more accurately than any other device. Chest strap does need to sync with either phone app or smart watch to keep tracking the data. Good chest strap should have good skin contact and does not move around while exercising, which can interferes with the signal.
The use of PPG (photoplethysmography or optical sensor) we see on watches have been around for about 5-6 years. What its measure is blood volume changes at the surface of skin and not electric signal from the heart. This can become an issue because every time the device moves the reading of the heartrate may vary.
More accurate device type next to the chest strap is forearm strap. Reason is they have a better skin contact and even while moving around the LED sensor does not move. Watch on the other hand, it slides and even when strapped tightly as the wrist move the skin and bone moves which can make the reading less accurate do to introducing noise to the signal. If you wear a watch to track heartrate, you may have come across the issue of reading the heart rate to being low while you are exercising hard and at rest when you are relaxed you see your heartrate being high.
Therefore, if you want to track your heartrate or other measurements more accurately, I suggest investigating heart rate chest strap or forearm strap which they can sync with your phone and smart watches. Personally, I track with heartrate chest strap. When I'm doing outdoor training, I will use my watch to track my pace while tracking my heartrate through heartrate strap.
Why Track Heartrate While Exercising?
Monitoring heartrate while exercising to me is like checking the speedometer while driving the car. Depending on your objective you can vary how much effort you should be putting into your exercise.
What I also want to monitor is my recovery after each set, especially if I’m doing zone 3,4 training. I want to see how much heartrate I can recover in one minute. Regardless of what effort I put in, I want to see my heartrate drop below 130 within a minute, that’s usually 30-35 beats drop from my working heartrate. By having tracking device, I have better understanding of my performance not just from how much I can lift but also how much I can recover.
By having an option to monitor heartrate, I can avoid guess work. Unlike when I used to play competitive soccer where I have practiced and trained for 12-14 hours a week, I only have 4-6 hours of training hours in a week because of work and family. To take a benefit of each and every hour, I don't have time for overtraining or undertraining which can lead to poor results, which I have experienced. Even with monitoring heartrate there may be some error in programming, however, I can minimize the error far greater than just guessing.
There are so many high end devices (>$500) out in the market that claim the accuracy of the data but how it is reading the data need to be understood before purchasing.
Body Composition and Device
There are several type of devices that can track your body composition. Device price can range from $20 to over $10k. These tools uses device called bioelectrical impedance analysis (BIA) device. BIA device calculate body composition by running a small electrical current. Depending on tissues (fat, muscle, bone, etc) water content varies. BIA reads and calculate this difference in electrical conductivity. You can find this BIA device on smart scales and hand held body fat analyzers. Little side note. Muscles and body water can has lower resistance (or high conductivity) towards electric current compared with body fat.
BIA device has 3 different pattern, hand-to-hand, foot-to-foot, and hand-to-foot. Hand-to-hand BIA machine can be very useful since it is generally smaller device. The measurement is done through upper body. Foot-to-foot BIA machine can be seen in smart scale with four electrodes. Low level of current passed through lower body to measure and calculate body fat. Hand-to-foot BIA device use electrodes on foot plate as well as electrodes at the grip, which allows to monitor the entire body.
When using BIA machines, it is important to follow protocols as much as possible just like when you go for blood panel with you doctor. Things like caffeine and alcohol usage should be avoided 24 hours prior to measurement. These chemicals can lower the body water and will have interference to the measurement. Eating and exercise also need to be done 3 hours prior to the measurements. When monitoring body composition, it is ideal to measure on daily basis for at least 14 days. What this will do is to help you understand your body trends along with understanding of the device that you are using to monitor your body composition.
It is also important to keep in mind that these machines does have marginal error and can fluctuate easily with simple thing like drinking water. So use the data as guide, not as definite tool to make judgement on your exercise or nutrition. What is more important is how your clothes fit, decrease in waist and hip circumference, increase in resistance for your exercises, and how you see in the mirror. Using sophisticated devices are great since it quantify your progress, however, I do see an issue in dwelling over the number though there are progress that is happening elsewhere.
My Input On Device
Collecting data can be fun. With collection of data, you can see the pattern of how you are doing with your plan.
There are new devices that can monitor so many different variables that can help you understand how your exercise and nutrition is going and what adjustment you'll need to make to advance to the next level. Technology is advancing to the point we can monitor pretty much any thing from our sleep, heartrate, heartrate variability(HRV), body fat, muscle mass and so on. What device you should invest on is based on what do you want to monitor.
Certain devices does require proper understanding. For example, monitoring your heartrate during your training is great but do you understand what it means? What change should you look for? Before you purchase any device, study the device and metrics that you are wanting to monitor. Some devices are expensive so you don't want to waste your money on unknow.
Kota Shimada
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