Overview: The Garmin Forerunner 645 GPS Running Watch
provides advanced running dynamics, and performance monitoring tools to help you
make the most of your workout. It also adds the convenience of Garmin Pay to let
you wirelessly pay for purchases with your watch. The watch's dimensions are:
- Watch: Width 1.723", Height 1.718",
- Watch Band: Width 0.785", Length 9.5" (including buckle)
-- fits wrists between 5" and 8" in circumference.
- Weight: 1.47 ounces
Garmin Pay: The Garmin Forerunner 645 features the Garmin
Pay contactless payment solution. Garmin Pay lets you pay for purchases quickly
without your wallet or phone. It works almost anywhere you can make contactless
payments. All you have to do is enter your passcode, select the credit card you
want to use from your virtual wallet, and hold your wrist near the card reader.
Your card number is not stored on your device, or passed to merchants when you
pay, so it's private and secure. Garmin Pay works with many major credit and
debit cards from
banks, including Visa and MasterCard.
GPS Receiver: The Forerunner 645 features a high-sensitivity GPS receiver
to accurately pinpoint and track your location while you're running, hiking,
skiing, biking, or swimming. It keeps track of your
personal records, and lets you know when you have set new ones. The Forerunner
645 provides constant feedback, including the distance traveled, elapsed time,
pace, lap time, and speed. The built-in barometer, altimeter, and electronic
compass let you keep your bearings when your activities take you off the beaten
path. With Garmin's Elevate heart rate technology, you can
continuously monitor your heart rate. After your run, you can upload your results to the
Garmin Connect online community.
Elevate: On the back of the Forerunner 645 is
an optical sensor with Garmin's Elevate heart rate technology that shines light onto your
skin and measures the amount of light returned. The sensor detects slight
changes on your skin as your heart pumps blood and determines your heart rate
using a sophisticated algorithm. The back of the watch has a light seal to block
out ambient light for accurate results. You can broadcast your heart rate data
to other Garmin devices, such as an Edge cycling computer or a VIRB action
Note: The Forerunner 645 is compatible with optional ANT+
devices, including the
Heart Rate Zones: Heart Rate Zones are used by many athletes
to indicate the level of activity, and to measure their cardiovascular strength.
You can let the Forerunner 645 set your heart rate zones based on your user
profile, or manually enter heart rate values and ranges for each zone. The heart
rate zones are expressed as a percentage of your maximum heart rate, and are
expressed in color codes on the device's display: Poor 0-40% (Red), Fair 40%
(Orange), Good 60% (Green), Excellent 80% (Blue), and Superior 95% (Purple).
Running Dynamics: The Forerunner device, when paired with
Running Dynamics Pod, HRM-Run or HRM-Tri accessory, can help analyze your running form. The
accelerometer in the accessories can measure torso movement and
calculate the following running metrics: Cadence (number of steps per minute),
Vertical Oscillation (your bounce when running), Ground Contact Time (amount of
time you spend on the ground while running), Ground Contact Time Balance
(left-right balance of your ground contact time), and Stride Length (measured
from one footfall to the next). You can view your running metrics as a color
gauge on the display, showing you how your running data compares to those of
Water Resistant: The Forerunner 645 has a 5 ATM water
rating, which means it can withstand pressures equivalent to a depth of 50
meters (164 feet). Not only can you run in the rain and wet weather, you can
even swim while wearing the device (see note below). The device also has a wide operating
temperature range of -4° to 140°F.
Note: To record your heart rate while swimming, you must
use the optional HRM-Tri or
HRM-Swim heart rate monitors.
Swimming Metrics: You can analyze your swimming workout
using the Forerunner and the chest-worn HRM-Swim. The device offers preloaded
swim profiles for open water and pool swimming, and metrics for both (distance,
pace, stroke count/rate, calories, etc.). The unit can calculate your SWOLF, or
swim efficiency score, which is the sum of the time for one pool length and the
number of strokes for that length.
Color LCD: The Forerunner 645 features a 1.2" diameter
color LCD screen with a resolution of 240 x 240 pixels. The display has a
backlight timer that can be set to 8, 15, 30, or 60 seconds, or Stays On. The
backlight can be turned on manually, or with the touch of a key or when you
receive an alert.
High-Sensitivity GPS Receiver: The Forerunner 645
features a high-sensitivity GPS receiver with GLONASS, which locates your
position quickly and keeps it locked onto positioning satellites, even near tall
buildings or under tree cover. You can turn off GLONASS to save battery power if
your GPS signal is strong.
Accelerometer: The built-in accelerometer can accurately
calculate your speed and distance when running indoors or on a treadmill, when
the GPS can't be used. The accelerometer is self-calibrating, and the speed and
distance accuracy improves after a few outdoor runs using GPS.
Rechargeable Battery: The Forerunner 645 has a built-in
Lithium-Ion rechargeable battery. A 22" data/charging cable is
provided for charging the battery and uploading your training data. Charging a
fully depleted battery takes approximately two hours. Typical
battery life varies according to the mode you're in:
- Watch Mode: Up to 7 days with activity tracking,
smartphone notifications, and wrist-based heart rate.
- Activity Mode: Up to 14 hours in GPS mode and
wrist-based heart rate.
Bluetooth Connected Features: The Garmin Forerunner 645
features Bluetooth Smart wireless technology that allows you to pair the watch
to your smartphone or mobile device through the Garmin Connect Mobile app. When
connected via Bluetooth, you can do the following: Phone notifications, LiveTrack, GroupTrack, software updates, workout and course downloads, Connect
IQ, social media interactions, weather updates, audio prompts,
Find My Phone, and Find My Watch.
Locating A Lost Phone/Watch: The Forerunner 645 can help you
locate your phone if it is still paired and currently within range. As you
search, the Find My Phone widget will display the Bluetooth signal strength and
sound an audible alert to help you find your phone. Similarly, you can find your
lost Forerunner using your phone when they are paired and within range.
Wi-Fi Features: In addition to Bluetooth, you can connect
the Forerunner 645 to the internet via Wi-Fi. While connected, you can perform
software updates, upload activity data to your Garmin Connect account, and
search for and select workout and training plans to send to your device.
Connect IQ: Through Garmin's Connect IQ site, you can
customize your Forerunner with watch faces, data fields, widgets, and apps. You
can download Connect IQ features to your device when paired with your smartphone
(Bluetooth) or connected to your computer (USB cable).
History: The Forerunner 645 has a small amount of memory for saving activity data. Your history displays the date, time of day, distance,
run time, calories, average pace or speed, and heart rate zone data. When the memory is full, your oldest data
is overwritten. History is not recorded while the timer is stopped or paused.
Watch Functions: When you're not working out, the Forerunner
645 can be used as a basic watch, displaying the time and date, along with an alarm,
timer, and a stopwatch.
The time is automatically set by the GPS receiver (or manually, if desired), and
can be displayed in 12-hour or 24-hour format. The FaceIt watch face creator in
the Garmin Connect community can be used to customize your device.