Garmin Forerunner 645
GPS running watch with built-in heart rate monitor (Sandstone)
Our take on the Garmin Forerunner 645 by Crutchfield's Ken Nail
A serious training tool
If you're a serious runner, you want a serious tool on your wrist. There aren't many more capable than Garmin's Forerunner 645 running watch. It's built to record all the important metrics of your run while providing feedback that'll help you up your game. Forerunner also boasts battery life that'll cover the distance, whether you're doing a local 5K or stepping onto the trails for a 50K. You can track the data by selecting from a variety of data fields, or customize the display with Garmin's Face-it™ app, changing the background to any picture stored in your smartphone.
Garmin's smart notifications work with your smartphone to let you receive texts, emails, and alerts on the watch screen. And Forerunner 645 automatically uploads your workout to Garmin Connect, where you can share it with your friends through social media or many popular fitness-tracking apps. Garmin's Live Tracking feature lets your family friends track you in real time — a great safety and race day feature. Forerunner 645 works with Garmin Pay, too, so you can use your watch to buy that post-run snack.
Built-in heart rate monitoring
I've learned through hard experience that heart rate monitoring is an essential tool for getting the most out of a training cycle. There's really no better way to ensure that you push hard enough during your key workouts and that you back off enough on the intensity when you need recovery. Forerunner 645's wrist-based monitoring technology makes it easy to monitor your heart rate and hit your target zones, so you'll know when you need to dial it up and when you need to take it down a notch.
Forerunner 645 offers great tools and analytics for runners, recording data on cadence, ground contact time and vertical oscillation, along with all the usual pace and time metrics you're used to. And using the data it records with its heart rate monitor, it will estimate and track your VO2 max, predicting your performance and suggesting training paces.
If you're joining the growing ranks of the trail running community, Forerunner 645 has tools you'll appreciate. It'll measure your total ascent and descent in the mountains, and the altimeter will clue you in on how many more feet of vertical remain before the top of the mountain. Garmin's TracBack feature makes it easy to retrace your steps if you've taken a wrong turn, too.
Mix it up
Cross-training should be in every runner's training program, and Forerunner 645 is well-equipped for these sessions. When you're in the pool, this watch tracks your distance, pace, stroke count, and more. And quit worrying about keeping track of laps during those long pool sessions — it'll count those for you too. Riding your bike? Forerunner 645 will track your distance and pace like a champ.
- GPS/GLONASS multisport training watch with color illuminated display
- wrist-based heart rate measurement
- compatible with Garmin Connect, Strava, and popular training apps
- text and email smart notifications
- compatible with Garmin Pay
- 1.2" LCD display (240 x 240 pixels)
- built-in rechargeable lithium ion battery allows up to 7 days operation in Smartwatch mode; 14 hours in GPS mode
- time/date, alarm, timer, chimes, and vibration watch functions
- 5 ATM water rating
- GPS speed and distance, AutoLap, AutoPause, interval trainer, heart rate, calorie counter, and lap fitness functions
- VO2 max estimator
- recovery advisor
- race predictor
- records personal records
- swimming metrics and stroke recognition
- pool swimming lap counter
- point to point, breadcrumb, and TracBack GPS navigation
- elevation profiles and ascent/descent tracking
- altimeter, compass, and thermometer
Activity Tracking Features:
- step counter with auto goal setter
- move bar
- sleep monitoring
- 1.75"W x 1.75"H x .55"D
- weight: 1.45 oz
- warranty: 1 year
- Our 60-day money-back guarantee
What's in the Box:
- GPS sports watch with music (Sandstone band)
- 22" Clip-on USB data/charging cable (Type A USB)
- Quick Start Manual (English)
- Quick Start Manual (Spanish)
- Quick Start Manual (French)
- Important Safety and Product Information booklet
Garmin Forerunner 645 Reviews
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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", Depth 0.538"
- 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 major 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 camera.
Note: The Forerunner 645 is compatible with optional ANT+ devices, including the HRM-Swim, HRM-Run, and HRM-Tri.
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 the optional 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 other runners.
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.
Our Product Research Team
Why did you buy this?
My Polar M400 running watch is also my everyday watch so size and appearance are fairly important to me. That's why I selected the Garmin 645: It's a full featured running watch that looks great and has a 'thin' profile, relative to similar featured running watches. It reflects the direction that running watches should be headed by incorporating contemporary materials and styling with the latest technology. Looking forward to putting it through it's paces :) [ Mario Apr 19, 2018 ]