Fitness Trackers, Heart Rate Monitors, and GPS Devices
Monitoring Your Heart Rate
Each time your heart contracts, it pumps blood into your arteries. You can measure your heart rate the number of heart contractions per minute by using a heart rate monitor or counting your pulse beats. Modern heart rate monitors are inexpensive and accurate. Several companies make heart rate monitor apps that are used with smart phones to measure heart rate, distances, route maps, running or cycling speed, and calories burned. Counting your pulse is the traditional method of measuring heart rate. Each contraction of the heart produces a surge of blood that causes a pulse you can feel by holding your fingers against an artery. Heart rate is a good way to monitor exercise intensity during a workout. (Intensity is described in more detail in the next section.)
The two most common sites for monitoring heart rate are the carotid artery in the neck and the radial artery in the wrist (Figure 3.4). To take your pulse, press your index and middle fingers gently on the correct site. You may have to shift position several times to find the best place to feel your pulse. Don’t use your thumb to check your pulse; it has a pulse of its own that can confuse your count. (Use your middle and ring finger if you have a strong pulse in your index finger.) Be careful not to push too hard, particularly immune system The physiological processes that protect us from diseases such as colds, bacterial infections, and even cancer.
When feeling for the carotid pulse under the angle of the jaw, use very light pressure.
WELLNESS IN THE DIGITAL AGE
Technology has transformed the market for trackers and monitors. It is difficult to keep up with the latest exercise monitors designed as stand-alone units, smart phone apps, and GPS accessories. A heart rate monitor is an electronic device that checks the user’s pulse, either continuously or on demand. These devices make it easy to monitor your heart rate before, during, and after exercise. Some include global positioning system (GPS) receivers that help you track the distance you walk, run, or bike. Wearable fitness trackers, made by Adidas, Nike, Fitbit, Withings, and BodyMedia, among others, measure distance and steps covered, calories burned, and exercise intensity.
High-tech monitors such as the Nike Fuelband and Nike+Sensor and Adidas miCoach track daily activities including running and walking and sports like basketball. They track steps taken, distance covered, and calories burned. Fitness trackers allow you to keep track of your progress, compete against other people, and meet challenges.
Wearable Heart Rate Monitors
Most consumer-grade heart rate monitors have two pieces a strap that wraps around the user’s chest and a wrist strap. The chest strap contains one or more small electrodes, which detect changes in the heart’s electrical voltage. A transmitter in the chest strap sends the data to a receiver in the wrist strap. A small computer in the wrist strap calculates the wearer’s heart rate and displays it on a small screen.
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In a few low-cost monitors, the chest and wrist straps are connected by a wire, but the most popular monitors use wireless technology to transmit data to the heart rate monitor display. In advanced wireless monitors, data are encoded so they cannot be read by other monitors that may be nearby, as is often the case in a crowded gym. A one-piece (or “strapless”) heart rate monitor does not include a chest strap; the wrist-worn device contains sensors that detect a pulse in the wearer’s hand.
Monitors in Gym Equipment
Many pieces of workout equipment including newer-model treadmills, stationary bikes, and elliptical trainers feature built-in heart rate monitors. The monitor is usually mounted into the device’s handles. To check your heart rate at any time while working out, simply grip the handles in the appropriate place; within a few seconds, your current heart rate will appear on the device’s console.
Heart rate monitors can do more than just check your pulse. For example, most monitors can tell you the following kinds of information:
• Highest and lowest heart rate during a session
• Average heart rate
• Target heart rate range, based on your age, weight, and other factors
• Time spent within the target range
• Number of calories burned during a session
Some monitors can upload their data to a computer, so information can be stored and analyzed. The analytical software can help you track your progress over a period of time or a number of workouts. Monitors with GPS provide an accurate estimate of distance traveled during a workout or over an entire day.
Heart rate monitors are useful if very close tracking of heart rate is important in your program. They offer several advantages:
• They are accurate, and they reduce the risk of mistakes when checking your own pulse. (Note: Chest-strap monitors are considered more accurate than strapless models. If you use a monitor built into gym equipment, its accuracy will depend on how well the device is maintained.)
• They are easy to use, although a sophisticated, multifunction monitor may take some time to master.
• They do the monitoring for you, so you don’t have to worry about checking your own pulse.
When shopping for a heart rate, fitness tracker, or exercise GPS monitor, do your homework. Quality, reliability, and warranties vary. Ask personal trainers in your area for their recommendations, and look for product reviews in consumer magazines or online.
when taking your pulse in the carotid artery (strong pressure on this artery may cause a reflex that slows the heart rate).
Heart rates are usually assessed in beats per minute (bpm). But counting your pulse for an entire minute isn’t practical when you’re exercising. And because heart rate slows rapidly when you stop exercising, a full minute’s
worth of counting can give inaccurate results. It’s best to do a shorter count 10 seconds and then multiply the result by 6 to get your heart rate in beats per minute. (You can also use a heart rate monitor to check your pulse. See the box “Fitness Trackers, Heart Rate Monitors, and GPS Devices” for more information.)
Interpreting Your Score
Once you’ve completed one or more of the assessment tests, use the table under “Rating Your Cardiovascular Fitness” in Lab 3.1 to determine your current level of cardiorespiratory fitness. As you interpret your score, remember that field tests of cardiorespiratory fitness are not precise scientific measurements and have up to a 10-15% margin of error.
You can use the assessment tests to monitor the progress of your fitness program by retesting yourself from time to time. Always compare scores for the same test: Your scores on different tests may vary considerably because of differences in skill and motivation and quirks in the tests themselves.