Comparison Garmin Forerunner 235 vs Garmin Forerunner 225

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 material from which the transparent cover of the display is made.

— Plastic. Inexpensive, moreover, quite durable and impact-resistant material: even with a strong impact, the plastic is more likely to crack than crumble into fragments. At the same time, scratches easily appear on such a surface, and over time it inevitably becomes cloudy. Because of this, plastic is found predominantly in inexpensive wearable gadgets.

— Glass. In this case, it can mean both classic silicate glass (the same as, for example, in windows), and some original types of impact-resistant glass that are not related to Gorilla Glass(see below). Regular glass costs more than plastic, but not by much, and it looks better and stays clear longer due to its scratch resistance. The main disadvantages of this material are fragility and a tendency to crumble into sharp fragments upon impact. Impact-resistant glass types are devoid of this drawback to one degree or another, but they are also more expensive. According to the price category of the gadget, you can quite accurately determine what kind of glass it uses — ordinary or shock-resistant.

— Sapphire. The coating made of synthetic sapphire is used exclusively in premium-class gadgets — this is due to the complexity of its production and, accordingly, the high cost. On the practical s...ide, sapphire is extremely scratch resistant (it is only possible to scratch such glass with a diamond or special tools), but at the same time it is fragile and easily breaks from impact.

— Gorilla glass. A family of shock-resistant glass types created by Corning and widely used in modern electronics, including wearable gadgets. In addition to strength, Gorilla Glass is also distinguished by good scratch resistance, while being relatively inexpensive (by the standards of such a coating), which has led to their popularity. However, the specific properties of such glass depend on its version; Here are the options that are relevant for modern wearable devices:

• Gorilla Glass v3. The oldest current version was released in 2013. Nevertheless, even such a coating is noticeably superior to traditional glass (not to mention plastic) in terms of transparency and scratch resistance.
• Gorilla Glass v4. Version released in 2014. A key feature was that the development of this coating focused on impact resistance (whereas previous generations focused mainly on scratch resistance). As a result, the glass turned out to be twice as strong as in version 3, despite the fact that its thickness was only 0.4 mm.
• Gorilla Glass SR+. The first version of Gorilla Glass, designed specifically for smartwatches and other miniature wearable gadgets; presented in 2016. According to the creators, the scratch resistance of such coatings approaches those of sapphire glass while maintaining the main advantages of Gorilla Glass — high strength and transparency. In general, for this material, superiority over "alternative options" is claimed by 70% in terms of strength specs and by 25% in terms of optical properties.
• Gorilla Glass DX. Another type of glass, specially designed for wearable devices. It was released in 2018 at the same time as the DX+ version (see below). Of the key improvements in Gorilla Glass DX, in particular, increased anti-reflective properties and an increase in the contrast level of the visible image by 50% are announced; the latter, among other things, allows you to reduce the actual brightness and, accordingly, the power consumption of screens without compromising image quality, which is especially important for miniature wearable devices. And this material differs from the DX+ type coating, on the one hand, by lower scratch resistance, and, on the other hand, by higher anti-reflective specs.
• Gorilla Glass DX+. Almost the same as the original version of DX, related to the same specialization — wearable wearable gadgets and other miniature devices. At the same time, DX + has a higher scratch resistance, but has slightly worse anti-reflective specs. Otherwise, these types of coverage are almost identical.

The presence of a slot for memory cards in the design of the gadget.

Such a slot allows you to expand the total amount of memory by supplementing the built-in storage (see above) with a replaceable card. And in some models, the built-in drive may not be available to the user at all (only basic firmware files are stored there), and the memory card is the only option for user storage.

The advantage of replaceable memory cards over built-in storage is that it is much cheaper in terms of gigabytes of volume; at the same time, cards are issued in different volumes, which allows you to choose the option that is optimal in terms of price and capacity. In addition, removable media can be used to exchange data with another device (smartphone, laptop, etc.) — although that wearable gadgets usually use miniature microSD cards, and devices like laptops use full-sized SD cards. Also note that these same microSD cards are presented on the market in several generations, and the compatibility of watches with a particular card needs to be specified separately.

The time that the gadget can work on one battery charge (or the supplied battery) in normal use.

Normal mode, as a rule, means working with a relatively low load. At this time, the display can display some data, and basic functions can also work (counting steps, periodically checking heart rate, etc.), but in any case, power consumption is low. Therefore, the operating time in normal mode can be quite impressive, up to several weeks, or even months. However, when choosing, it doesn’t hurt to also pay attention to the stated time in active mode (see below) — especially if a long operating time is critical, or you plan to use the gadget intensively. The actual autonomy of the device will most likely be somewhere in between these two values, depending on the actual load. If only the time in normal mode is indicated for the gadget, you should choose with a certain reserve.

The time that the gadget is able to work on one charge of the battery in the active mode of use.

For watch-phones (see “Type”), this usually means a talk mode, for other gadgets, an intensive work mode when numerous features and sensors are used and there is a constant exchange of data with a smartphone/tablet. However, the specific understanding of the "active mode" for different manufacturers may vary: some indicate the time at maximum performance (that is, in fact, guaranteed battery life), others — in some kind of "average mode". However, anyway, this is a fairly clear parameter that describes the battery life of a particular model quite well (and is much closer to real indicators than the time in normal mode mentioned above).

Note that for models with a GPS sensor (see "Navigation"), the specifications may additionally specify the time of active operation using such a sensor. See "Operating time (GPS)" for details.

Swivel ring around the round dial of the smartwatch. Bezel exists for a decorative and protective purpose, and in many models it has additional markings and provides a number of special control options. By rotating it, you can navigate through the menu of the smartwatch, and it also simplifies interaction with the touch screen of the wearable device. On the bezel, special marks are often applied for the operation of the watch dial in the timer or stopwatch mode. The specific implementation of the features assigned to the ring depends on the specific model of smartwatch.

— Metallic. The metal bezel has high mechanical strength. Usually it is made of stainless steel.

— Plastic. A low cost version of the bezel, which is found in smartwatch models with plastic cases.

Body colours in which the gadget is available. Note that in this case "stainless steel" is only the name of the shade, the body material itself may be different (for example, aluminium).

The colour of the strap that the gadget comes with. If several options are indicated in this paragraph, this, usually, means that the user can pick the colour of his choice. Other options may be envisaged — for example, the presence of several straps in the kit, or the possibility of such a set at the request of the user — but they are much less common.

The type of clasp used on a gadget's strap or bracelet.

The most common types of clasps today are the classic buckle, folding clip, folding lock, magnet, snap fastener, and Hook-and-loop. If several options are indicated in the specs at once, it means that the gadget is supplied or can be supplied with different strap options using different types of fasteners. Here is a detailed description of each type:

– Classic (with buckle). Clasp resembling a belt buckle; originally used in traditional wristwatches, but nowadays it has become widespread in smart gadgets. On one half of such a fastener there is a U-shaped or similar frame with a special pin, on the second — a row of holes. When fastening, the second half is threaded through the frame, and the pin is fixed in one of the holes. At the same time, by choosing a particular hole, you can adjust the size of the strap. In addition, the advantages of the classics are reliability, neat appearance and compatibility with many strap materials (with the exception of metal bracelets).

— Clip (unfolding). An option for metal bracelets. The most widespread type of clip, consisting of two curved plates connected by an axis. When unfastened, they open like a book, increasing the overall length of the bracelet and allowing you to easily r...emove the watch from your hand, and when fastened, they fold close to each other and are fixed, securing the bracelet on your wrist. Another, less popular variety is the “butterfly”, which has two flaps that, when opened, rise like wings. In general, the clips are very easy to use, but difficult to set up. They fasten and unfasten with literally one click, but it’s impossible to reconfigure the size of a bracelet with a clip “on the go” — you have to disconnect and reconnect special latches, which requires an additional tool and some skill.

— Magnetic. A fastener in which a strong permanent magnet plays the role of a latch. Such devices are simple and convenient both in use and in adjustment: for fastening and unfastening, it is enough to “stick” or “unstick” a magnet, and size adjustment is carried out right at the time of fastening — by tightening the strap to the desired length. The main disadvantage of such a clasp is that it can only be used with metal bracelets made of magnetic alloys — for example, steel.

— With lock. A clasp that resembles the buckle described above, but has a slightly different principle of operation. On one side of the strap with such a clasp there is a latch pin, on the other side there is a loop of a D-shaped or other shape, as well as a number of holes. When fastening, the side with the pin is threaded into the loop and then fixed in one of the holes; By choosing one or another hole, you can adjust the length of the strap. This design is especially suitable for rubber straps, it is simpler and at the same time more reliable than the buckle, which can also be used with such straps.

— Hook-and-loop. Classic hook-and-loop closure, used exclusively with fabric straps. Like magnetic clasps (see above), such clasps allow you to very accurately adjust the length of the strap right in the process of fastening. Among the disadvantages of Hook-and-loop, in addition to restrictions on the materials of the strap, it is worth noting the tendency to reduce reliability as it wears out. Therefore, nowadays, this type of fastener is quite rare, and is almost never used as the only one available — usually Hook-and-loop is supplemented with another option, for example, a latch.

— Folding lock. Clasp in the form of a detachable lock, the halves of which are on different halves of the bracelet. It is used with finely woven metal bracelets, the so-called "Milanese" ones; at the same time, one half is fixed motionless, and the second can move along its part of the bracelet — in this way the length is adjusted. A tool may be required for adjustment, but the procedure itself is simple — much easier than with clips. And the low prevalence of folding locks is mainly due to the fact that Milanese bracelets are rarely found in smart wearable gadgets.