Comparison Apple Watch 6 Aluminum 40 mm vs Apple Watch SE 40 mm

Types of sports and medical data collected by the gadget (plus some features of a similar purpose, such as sleep tracking, smart alarms, stress levels and women's calendar). Note that the features from this list can be found not only in specialized fitness trackers (see "Type"), but also in more traditional devices like smartwatches. Here are the most popular options:

— Pulse rate. Heart rate is one of the most important physiological parameters of a person. So that sports training is as effective as possible, the heart rate must be in a certain range (the specific value depends on the purpose of the training and the personal data of the user). And for some illnesses and treatments, a faster or slower heart rate can be an important signal, including a warning of danger.

— Pressure (tonometer). A sensor that measures the user's blood pressure. Note that the accuracy of such a sensor is usually quite low, the measurement error can be 10% or even more; so it will not replace a full-fledged medical tonometer. On the other hand, a gadget with this feature is quite capable of detecting a critical increase or decrease in pressure, which will allow you to take the necessary measures in a timely manner.

— ECG. A sen...sor that allows you to get detailed data about the work of the user's heart. Note that such a sensor is not a full-fledged electrocardiograph — in fact, it is an advanced type of heart rate monitor that can track the features of the heart rhythm. However, even this is enough to detect some dangerous phenomena — for example, atrial fibrillation, which at first is imperceptible to a person — and take appropriate measures in time.

— The blood oxygen. A sensor (the so-called pulse oximeter) that determines the saturation of the blood with oxygen (saturation); at the same time, the measurement is carried out by a non-invasive method — without punctures and other damage to the skin. Like most medical sensors in wearable gadgets, it is not accurate and is not a full-fledged medical device, but it is quite capable of responding to a critical decrease in the level of oxygen in the blood. It is believed that the presence of a pulse oximeter is relevant primarily for certain diseases, when saturation may decrease due to the disease itself or the characteristics of the treatment being taken. However, this feature can also be useful for quite healthy users who often travel at high altitudes — primarily climbers and aeronauts.

— Body temperature. The presence of a sensor for measuring temperature allows you to take measurements without the use of thermometers. Naturally, errors can occur, so a slight deviation from the norm may not be determined, but the device will easily fix a significant increase in temperature.

— T° of the environment. Even though smartwatches are worn on the body, the built-in sensors in them are usually designed to measure the ambient temperature. This information can be useful both for a general assessment of the surrounding conditions, and for specific purposes — in particular, weather forecasting. It is not uncommon for watches with this feature to also have a barometer (see "Navigation").

— Number of steps. The traditional pedometer is a feature for counting the number of steps taken by the user. These measurements usually use data from the accelerometer, and the results are quite accurate: most modern accelerometers are well calibrated and are quite capable of distinguishing tremors during steps from hand waves and other extraneous movements. The exception is trips in land transport: many wearable gadgets perceive shaking as steps, which should be taken into account when evaluating the results.

— Distance travelled. Measurement of the total distance traveled by the user. For this, either data from a pedometer or a GPS module are usually used (see "Navigation"); each option has its own merits. So, the pedometer is cheaper, it can be used even in rooms without windows, where the signal from satellites does not reach, and on simulators like treadmills, where the user does not move relative to the ground. GPS, in turn, gives higher accuracy, especially over long distances, and is not prone to false positives in vehicles. In some advanced gadgets, these methods can be combined — this is not cheap, but it allows you to combine the advantages of both options and achieve maximum accuracy.

— Movement speed. Determining the speed of the user's movement. As with distance travelled, measurement can be done in a variety of ways; see above for more details. Also note here that many gadgets with this feature are able not only to determine the current speed, but also to constantly record its value and display various indicators: the maximum achieved speed, the average value for training, etc.

— Energy spent (calories). Measurement of the number of calories burned by the user in the process of movement. These data are rather approximate, as they are calculated by indirect parameters (speed and range of movement, personal specs of a person, etc.). However, even this accuracy is quite enough to determine the overall effectiveness of training.

— The amount of fat burned. Measuring the amount of fat burned per workout. As in the case of calories (see above), the result of such measurements is quite approximate. However, in fact, absolute accuracy is not required, and fat loss data can be a powerful motivator.

— Activity time. A measurement of the total time during which the user is actively moving. In many models, such metering may provide additional options, such as fixing several periods of activity with breaks between them and determining the ratio between the time of movement and the time of rest.

— Smart alarm. An alarm clock that monitors the user's sleep phases and gives a signal to wake up at the optimal time for this. Human sleep consists of alternating phases, and waking up in the unfortunate phase creates a feeling of lethargy and fatigue, even if there was enough time to sleep. A smart alarm clock avoids such situations; its work is based on tracking the pulse, breathing rate and other parameters that differ depending on the phase of sleep. Note that the deviation of the signal from the set time can be up to half an hour, but this is usually a deviation towards an earlier rise. As a result, the risk of being late with a smart alarm clock is close to zero, and the lack of sleep time is compensated by the optimal moment of awakening.

— Sleep tracking. Sleep quality assessment is based on data from on-board sensors of fitness trackers or smartwatches. In particular, the heart rate monitor controls the number of contractions of the heart muscle, the accelerometer controls the user's movements. A blood oxygen sensor, if available on the wearable, improves the accuracy of sleep quality data collection. According to the readings of the sensors, the moments of entering and exiting the deep sleep phase are recorded. It is during this period that the restoration of the nervous system and the accumulation of energy for the coming day take place. In deep sleep, a person can completely reboot and gain strength, while in REM sleep, brain activity practically does not differ from the state of wakefulness. The sleep quality analysis feature helps you determine the best time to go to sleep and provides personalized recommendations to improve your night's sleep.

— The level of stress. The level of stress of the body allows you to evaluate the metric that determines the variability of the heartbeat — the difference in time between successive contractions of the heart muscle. Respiration rate, maximum oxygen consumption and excess oxygen consumption after exercise are also taken into account. The stress level score gives a clear picture of the user's experience during the day, however, the value of this parameter is in determining the most optimal body regimen for training. A high heart rate variability usually indicates you are in good shape for playing sports, while a low one can indicate fatigue, dehydration, or feeling unwell. All this directly affects the ability to train effectively. There are no clear units for measuring the level of stress — in smartwatches, the parameter is usually shown as a scale from 0 to 100, often indicating the number of hours the body is under stress and the time it takes to recover to a normal state.

— Women's calendar. The tool for tracking the menstrual cycle keeps abreast of the events of the expected dates of the menstrual period, allows you to determine the most favorable days for conception, helps to notice alarming symptoms in time and prevent many diseases in case of cycle disorders. Based on your total cycle length, the device calculates a predicted date for your next period. The women's calendar records cycle dates, fertility windows, and the day of ovulation. By adding your own notes to it, you can track fluctuations in sleep, appetite, fitness, mood changes and predict well-being for a particular day.

In addition to those described above, more specific types of measurements can be found in modern wearable gadgets.

The model name of the processor (CPU) installed in the watch. Knowing this name, you can find detailed data on a particular CPU and evaluate its level and general capabilities. This is especially important due of the fact that these capabilities depend not only on the basic specs (number of cores, clock frequency), but also on specific design nuances.

— Built-in player. The presence of a player in the smartwatch allows you to use the gadget to listen to music. There is no need to connect to the phone for this. The songs will play directly from the watch. Therefore, these devices must necessarily have an impressive (as for a watch) amount of storage and be able to connect to headphones (for connection with headphones).

— Light sensor. A sensor that monitors the brightness of ambient light. One of the most popular ways to use this feature is to auto-adjust the brightness of the display: in bright light, it increases so that the image remains visible, and at dusk it decreases, which reduces eye strain and energy consumption. In addition, other more specific features may be provided — for example, turning on the screen when pulling back the sleeve of clothing.

— WiFi. A technology originally used to access the Internet via wireless access points, but more recently also used for direct communication between two devices (such a connection has several advantages over traditional Bluetooth). In wearable gadgets, the first option is most often provided, although the second is also found. However, the specific uses of Wi-Fi may be different depending on the device: accessing websites and various Internet services, remote communication with smart home systems, remote control of digital cameras and other electr...onics, transmission of the GPS- coordinates via Internet (in children's beacons), etc.

— NFC. Wireless communication technology over short distances (up to 10 cm). The methods of its application, including in wearable devices, may be different. One of the more popular options is using contactless payment (see below); however, the presence of such a function does not hurt to verify separately. Another common feature is the simplification of Bluetooth connection with a smartphone or tablet that also has NFC: instead of manual configuration, it is enough to bring one device to another — and they will automatically establish a connection, all that remains is to confirm it. Other ways of interaction may also be possible, for example, launching a “sports” application on a smartphone when bringing a fitness tracker to it. And theoretically, more specific options for using NFC are also allowed — for example, as a travel pass, ID, etc. Actually, in many models of wearable gadgets, the set of these methods is limited only by installed applications.

— Contactless payment. The possibility of using a wearable gadget for contactless payment. This feature is found only in models with NFC (see above); it actually turns the device into an analogue of a credit card with a chip and allows you to pay without taking the card out of your wallet — just bring your hand with the gadget to the terminal reader. This provides not only additional convenience, but also security. So, bringing the watch to the terminal is definitely easier than reaching into your pocket or purse for a credit card — especially if your hands are busy shopping. And instead of a traditional card, from which an attacker can copy basic details such as a number, CVV code and expiration date (for example, by “peeping” them with the built-in camera), a gadget is used that transmits this data in encrypted form and does not display it explicitly anywhere.
To use contactless payment, usually, you need to synchronize your gadget with your smartphone and set up such payment in the Google Pay or Apple Pay system. But to make payments, a smartphone is no longer required — many wearable devices are able to perform this feature completely autonomously (although this possibility still needs to be specified separately).

— Accelerometer. A sensor that determines the direction of gravity, as well as the accelerations acting on the device. This allows you to track two parameters at once: the current position in space and various physical influences (like tapping or shaking). Most often, the accelerometer is responsible for two main features: automatic rotation of the image on the screen, as well as the operation of the pedometer (in fact, the presence of such a sensor is almost guaranteed to mean the presence of a pedometer, see "Possible measurements"). However, there are other ways to use this sensor — for example, rejecting an incoming call when shaking the watch, turning on the screen when tapping on it, etc.

— Gyroscope. A device that allows you to track the turns of the gadget in one direction or another. Typically used in conjunction with an accelerometer. The gyroscope improves the accuracy of positioning in space (which has a positive effect on the quality of the pedometer and other similar functions), and also provides additional options for managing gestures. However, the specific applications of this sensor are highly dependent on the model.

— Camera. The watch/bracelet has its own built-in camera; its location and purpose differs from model to model. In some devices, the lens is located on the front panel, above the screen, and the matter is limited only to video communication and taking selfies, while others allow you to shoot “classic” photos or videos. At the same time, it is worth noting that anyway, the specs of such cameras are usually very limited — for example, the resolution rarely exceeds 2 megapixels, and autofocus is provided only in the most advanced models.

— Flashlight. Built-in flashlight — usually in the form of a small LED mounted directly in the case. Usually, it has a relatively modest brightness, but it can still be useful for simple tasks like lighting your path at night, lighting in a garage or basement, etc.