Comparison Garmin HRM Pro Plus vs Aqua M70C

— Pedometer. This category comprises devices primarily designed to count the number of steps taken by the user. Additional measurements in the design are directly related to step counting and may include movement speed, distance traveled, energy consumption, etc. Steps are typically counted based on accelerometer data, responding to the characteristic shaking during walking. Some pedometers use GPS modules instead of accelerometers, measuring distance traveled rather than individual steps. Another specific variety is designed for swimmers, measuring strokes instead of steps. Despite this difference, they share key features with traditional pedometers and are included in the same category.

— Heart rate monitor. Devices designed to track the user's heart rate and the corresponding calculations based on this data. They are not able to work with step counting — unlike pedometers and combination metres, see below. There are both devices with a built-in sensor, and with a remote one.

— Heart rate monitor/pedometer. Combined models integrate the functionalities of both heart rate monitors and pedometers, measuring both the number of steps and heart rate, along with related parameters. These devices offer versatility, but their development involves technical challenges that can impact measurement quality and overall cost. As a result, there are relatively few...models of this type available on the market.

— Pulse oximeter. These devices can measure both heart rate and blood oxygen saturation and typically resemble a characteristic "clothespin" attached to the finger. Using non-invasive methods, they determine blood oxygen levels without causing skin damage. While suitable for sports applications, they also find use in medical settings, serving as a means to monitor a patient's condition in the absence of more advanced medical equipment. However, due to the inconvenience of the finger "clothespin" during vigorous activity, these devices are more aligned with medical instruments in their intended use.

— Heart rate sensor. These models are external heart rate sensors meant for connection to other devices such as heart rate monitors, exercise equipment, or smartphones. They are not designed for stand-alone use. While these cardiac sensors have limited capabilities, this is not a drawback but a specific feature inherent in their application format. The expectation is that additional measurements will be conducted by an external device, and the sensor's role is to provide the necessary data for this purpose.

— Wrist. Worn on the wrist like a traditional watch, many models of these devices closely resemble electronic watches. This method of attachment is highly convenient, especially for heart rate monitors, as the device sits directly on the skin, allowing for easy integration of pulse sensors. However, for pedometers, wrist mounting has drawbacks due to various vibrations affecting accuracy. To compensate, devices require intricate accelerometer calibration or the use of a GPS module, both influencing the device's cost.

— Forearm. Placing the sensor on the forearm (parts of the arm from the elbow and above) is both easier and less inconvenient. However, the distance of the sensor from the heart can affect the accuracy of the measurement. Therefore, most of the cardio sensors are made exactly on the chest (see paragraph above).

— Chest. Secured on the chest with a specialized belt, this method positions the device close to the heart, ensuring highly accurate heart rate tracking. However, devices with this setup typically lack displays as checking them would be inconvenient. This configuration is exclusively employed in cardiac sensors (see "Type").

— Neck. Traditionally, these devices are attached to a cord or ribbon for wearing around the neck. While this is the standard method, many models offer versatility,...allowing them to be placed in a pocket. Some devices in this category are not designed for cord attachment at all and are somewhat loosely classified. Pedometers are commonly found in the "neck" device category.

— Shoes. Positioned on the upper part of shoes, typically where lacing is found in classic sneakers, this method is convenient for pedometers, ensuring accurate step tracking. However, it may not be compatible with all shoes, and using certain functions can be challenging, requiring bending over or removing the device to interact with the display. As a result, this option hasn't gained widespread popularity.

— Fastening with a clip. Featuring a universal clip or "clothespin" in its design, this allows the device to be easily attached to the edge of clothing, such as a belt, collar, or pocket. Common in classic pedometers (see "Type"), these devices don't require direct contact with the skin during operation. The clip attachment method is more versatile than mounting on shoes and, for some users, is even more convenient than wearing the device around the neck or on the wrist/shoulder.

There are models that have several purposes — usually, these are devices on wrist, supplemented with alternative options (for example, a clip).

— External. An external chest sensor is directly attached to the chest using a special belt, typically communicating wirelessly with the main unit. This communication can be through a universal interface like Wi-Fi or Bluetooth, a specialized one such as ANT +, or even a distinct natural frequency. This design ensures accurate measurements, allows flexibility in fastening the main unit of the heart rate monitor, and minimizes inconvenience. The sensors don't restrict movements much and have lenient requirements for dimensions and weight, contributing to cost-effectiveness. As a result, chest sensors are widely popular.

— Built-in. Built-in sensors refer to sensors installed directly in the main unit of the heart rate monitor, consistently in contact with the skin. This design is convenient as everything needed is housed in a single unit, reducing the risk of losing the sensor. They offer continuous heart rate monitoring, but the options for fastening are limited (see "Purpose"), typically restricted to the wrist due to the need for constant skin contact. Strict requirements for dimensions, weight, and the design's complexity impact the cost, and measurement accuracy is generally lower. Due to these factors, built-in sensors are not widely adopted.

— Finger sensor. A finger sensor reads heart rate data from the fingertip, typically the index finger. In...some wrist-mounted models, these sensors are integrated into the case, requiring touch for pulse measurement. Unlike built-in sensors, finger sensors don't provide continuous monitoring but offer higher accuracy. Another option is a clip-like "clothespin" attached to the fingertip, akin to sensors in medical equipment. While these allow constant pulse monitoring, they are less convenient for vigorous activity and are uncommon.

— Ear clip. Another type of "clothespin," in this case designed for attachment to the earlobe. These clips are smaller and less restrictive than finger clips, making them more suitable for active activities. However, achieving light and compact sensors with wireless connections is challenging, and additional wires can make the structure unwieldy. As a result, ear clips are uncommon, primarily found in neck-mounted models (see "Purpose").

The shape of the display provided in the design of the device. In this case, there are two main types of displays — round and rectangular. However, it is worth noting that such a division is very arbitrary, and the groups themselves are very extensive: for example, round displays are oval and egg-shaped, some of them resemble rectangles with extremely rounded corners; a classic rectangular display can be placed in a round case, etc. In addition, its shape practically does not affect the functionality of the display. Therefore, when choosing, you should focus not so much on the form as on the type of display (see below), the features of displaying various data on it and the general compliance with your aesthetic preferences.

The type of display provided in the design of the device.

— Monochrome. Monochrome displays in pedometers and heart rate monitors typically show one primary color, commonly classic black and white like electronic watches. Some variations use different main colors, such as blue or green, on dark or light backgrounds. While monochrome displays may not offer the richness and variety of information that color displays do, they are more cost-effective and widely prevalent across all price ranges, from budget to high-end devices.

— Coloured. Colour displays in heart rate monitors and pedometers can work with various primary colours, offering different functionalities and a range of displayed colors. However, these screens are generally simpler compared to other portable electronics like media players or smartwatches. While color screens provide more information and a visually appealing look, they come at a higher cost. The aesthetic value of color is often prioritized, even though there is rarely a practical need for a coloured display. As a result, this option is less common in heart rate monitors and pedometers.

— Is absent. The complete absence of a display indicates that the device is designed to be connected to an external device with a screen (smartphone, exercise machine, etc.). All heart sensors have this design, however, it is also found among other types of devices (see "Type") — for example, among pedo...meters mounted on shoes or on the shoulder (see "Purpose"), where it would be simply inconvenient to look at the built-in display.

The presence of backlight in the design of the display, which is equipped with the device.

Its own backlight allows you to see the image on the screen regardless of the ambient light — in other words, such a screen can be used even in complete darkness. Most often, it turns on for a short time, by pressing a special button — this allows you to minimize additional battery consumption. The exception is displays built on the basis of OLED matrices — in them each pixel is a separate luminous element, the image glows constantly, and energy savings are ensured by high efficiency and some design and software tricks.

Measurements and calculations that can be carried out with the device.

— Heart rate. Heart rate measurement in real-time is a crucial feature for devices with a heart rate monitor function and is primarily the main function for heart sensors and pulse oximeters. In fitness, heart rate is a key parameter, aligning with various training goals such as fat burning, maintaining shape, or cardiovascular strengthening. Many models can also detect critical situations like heart rhythm disturbances or excessive heart rate, providing user warnings. However, it's important to note that not all heart rate monitors or combined devices offer continuous monitoring; some models require touching the sensor for measurements. Therefore, for constant pulse data, ensure the selected device supports continuous monitoring.

— The level of oxygen in the blood. The pulse oximeter function measures blood oxygen saturation levels using a specialized sensor in a non-invasive manner, without puncturing or damaging the skin. It's important to acknowledge that the oxygen level sensor is not a certified medical device. However, it effectively responds to critical decreases in saturation, such as those experienced by climbers at high altitudes or individuals with specific respiratory conditions.

— Perfusion Index (PI). A parameter found exclusi...vely in pulse oximeters (see “Type”). Perfusion Index (PI) is a measure of blood flow in the finger being measured. The PI indicator is measured as a percentage and can vary from 0.3 to 20%. A value in the range of 4 – 7% is considered normal. If you deviate from this range, the saturation measurement results may be distorted.

— Number of steps. Step count measures the number of individual steps taken by the user, aiding in achieving recommended activity levels for a healthy lifestyle, fitness, or physical therapy. The function calculates steps taken in various ways, such as recording results for multiple sessions or days, displaying total and average numbers, remembering target values, and signaling their achievement. It's important to note that not all devices with a pedometer function (refer to "Type") support step count measurements. Some devices, designed for professional sports where movement speed is crucial, may prioritize other metrics over step count.

— Distance travelled. The function measures the total distance covered by the user. Basic models calculate distance in real-time, while more advanced ones can summarize results and work with target values. There are two main measurement methods: classic pedometers determine distance by multiplying the number of steps by the set step length (refer to "Individual settings"), while models with GPS use satellite navigation data (see "Features"). The first method has a larger error, but it's often not critical. The second method is more accurate but is costlier and may not work well in areas with weak satellite signals, such as dense urban areas or indoors.

— Movement speed. Measurement of the current movement speed. Like the distance traveled, this indicator can be calculated in two ways — by the number of steps or by data from the GPS module; see above for details on both methods. The simplest measurement option provides measuring the speed only at the current time, however, additional features may be provided — for example, building a schedule for a workout.

— Energy expenditure (calories). The function measures the amount of energy expended during a workout, commonly referred to as "burned calories". Monitoring energy consumption is crucial in weight management training programs as it helps track metabolism. However, it's essential to note that modern heart rate monitors and pedometers do not directly determine actual energy consumption. Instead, they estimate the number of calories based on factors such as heart rate, movement speed, number of steps, user's personal characteristics (refer to "Individual settings"), and other indirect parameters. Despite being approximate, these calculations are generally accurate enough for practical application.

— The amount of burning fat. The function calculates the amount of burned fat during a workout, typically measured in weight units such as grams. Similar to energy consumption, the device doesn't directly measure the actual fat burned but estimates it from various auxiliary data. The accuracy of these measurements is relatively low, and this parameter is not a primary focus in fitness. However, tracking the amount of fat eliminated can serve as additional motivation for users.

— Average/maximum heart rate. Calculation of the average and maximum value of the heart rate for a certain period of time (usually for one training session). These calculations are based on general information about the heart rate; about its meaning, see above.

— Activity time. The function measures the total duration of the user's physical activity, specifically recording only the time during which the device sensors detect the activity. Breaks in sessions are excluded from the recorded time. For instance, if you walked 1000 steps in 20 minutes with a 3-minute break, the recorded activity time would be 17 minutes. This feature distinguishes it from a regular stopwatch (refer to "Features") and enables accurate tracking of the duration and intensity of training loads.

Data transfer standards supported by the device.

— Wi-Fi. Originally designed for computer networks and internet access, Wi-Fi is now commonly used for direct communication between devices, notably in fitness devices. While internet connectivity is possible, it's typically for specific tasks like firmware updates or saving data to network storage. The prevalent Wi-Fi version, 802.11n, theoretically offers a communication range of up to 100m indoors and 200m in open areas (though real-world figures are more modest). Newer generations boast even greater ranges. Wi-Fi modules are essential in various portable electronics like smartphones and tablets, but it tends to be less power-efficient compared to Bluetooth and ANT+.

— Bluetooth. Developed as a universal standard for direct device-to-device connectivity, Bluetooth technology comes in several compatible versions. The latest version, Bluetooth 4.0, offers a connection range of up to 100m and incorporates a low-energy communication standard, making it more energy-efficient than Wi-Fi. This efficiency is especially beneficial for compact electronics like heart rate monitors and pedometers with limited space for a sizable battery. However, Bluetooth modules are somewhat less common than Wi-Fi, with certain tablets and laptops lacking support. This is a consideration when selecting a model with this data transfer method.

— ANT+. Designed specific...ally for sports equipment and remote control applications, ANT+ is a low-power wireless transmission technology. It facilitates connections between heart rate monitors or pedometers and various devices, including exercise machines, smartphones, and tablets. For devices with USB On-The-Go support, communication is possible through a special adapter. Higher-priced models may have built-in ANT+ support, eliminating the need for additional equipment.

The degree of water protection provided for in the design of the device.

The specified underwater depth for device functionality is often given, but it's important to note that these values are somewhat arbitrary and don't accurately reflect real-world water resistance. The assessments only consider static pressure, neglecting dynamic pressure created by movement, including immersion.

Effectively, genuine water resistance can only be claimed at a minimum of 30m. Even then, such capabilities only withstand minor exposure like rain. Brief water exposure, like swimming, might be permitted at 50m (not universally). For depths of 2 — 3m, 100m is necessary, and serious diving requires a minimum of 200m (or 300m for depths exceeding 20m).