Garmin Forerunner 645: Tune up your training!

The Garmin Forerunner 645 has all the highest accuracy distance tracking sensors in the market, a great wrist heart rate monitor and amazing running dynamics available. Paired with a Garmin HRM run you can measure your ground contact time, ground contact time balance, stride length, vertical ratio, cadence and vertical oscillation. You get everything you need to improve your times and to keep track of your training thanks to the recovery time option too. The Forerunner 645 has about everything that a running watch needs and it is not the priciest of the bunch. 

Sport Applications:
Even thought the Forerunner 645 fits into the category of “running” watches, this smart watch can do almost about anything on any sport. I sometimes use it for my soccer training sessions, sprinting sessions and even while playing tennis. In all 3 the watch is very good to register distances and instant velocities. I even used it for skiing in the snow once and it worked like a charm. Tried using the “indoor track” option when playing futsal at a closed stadium and the data was pretty convincing (not sure how accurate because I could not compare it to anything else though). Use it for gym sessions too, but I would definitely recommend to pair it up to a chest HRM when at the gym because the wrist heart rate will most definitely be mistaken with all the different hand movements. The strength tracker with sets and repetitions is very accurate when it comes to arm-involving exercises or anything that moves your wrist while performing. Unfortunately, this feature I dont use usually because I focus on my training instead of looking at the recorded repetitions my watch records. Nevertheless, it is there for you to use if you are not good at counting your own reps :P. 


(Click on the photo for a thorough explanation of these!)

Advanced Running Dynamics: 

All those running dynamics can be more than anyone needs, but they are great to spot any issues on your running technique and biomechanics. For example, when using these dynamics, I noticed that I was spending about 3% more time on my left leg than my right, probably because a previous surgery on my right ankle. After spotting this stat, I focused on trying to even-out that contact time and now I stay much close to 50-50 while running. Also, as a sprinter, I have always been a bit of a freak for contact time. I love seeing this dynamic, even for my short sprints of 100 meters which it seems to measure really well and can give you a good idea on where you can improve your technique for future personal records!

Everyday Use (battery life, waterproof, smart watch features):

I use the watch every day all day long! It looks good and is very comfortable to wear. It takes about an hour or less to charge and the battery life is pretty decent. When I am not training, it lasts more than a week and during training periods with GPS and music off it can be on for about 14 hours (with music on and GPS on it lasts 5 hours). So no need to worry about charging the watch every day if you exercise 2 or 3 hours a day which is great for amateur athletes. The watch is resistant to 5 ATM of water pressure, which means that you can swim comfortably anywhere just not made for diving. It works really well for swimming, giving you the strokes per minute, swolf and stroke length. Unfortunately, like all the wrist based HRM it will not be reliable underwater, but for everything else it works just fine. As a more sport based smart watch, it does not have that many widgets non-sport related. Spotify or music app is great for using bluetooth headphones though, works really well and very easy to use. You can see your message notifications but cannot respond to them. There is a cool feature “find my phone” which I thought I was never going to use, but I find myself using it about once a day hahaha. The weather widget is very helpful and will show you everything you need if you have recently paired it with your phone. But best of all, the smart watch features would be the garmin pay. I never have to worry again about bringing my wallet anywhere. No need to take some cash with you when getting going on a long run. With this watch if finding my wallet was hard enough before, now I do not see it for weeks because I do not really need it.

5 reasons to buy:
1.) Has every other sport to track while still being a top running watch
2.) Great detail running dynamics like contact time and contact balance when paired with the Garmin HRM run.
3.) Good price when compared to other similar smart watches
4.) Stylish Smart Watch even for casual-wear
5.) Great GPS accuracy and quick connection

3 Reasons not to buy:
1.) Has no Oxy-Meter
2.) Has no Garmin’s Body Battery
3.) Might have TOO much if you are a novice runner


If you’re looking for an intermediate priced smart watch to tune up your training, the Garmin Forerunner 645 is a great choice! Starting at a $399 retail price, this watch has everything any runner needs, and more.

On the other hand, I was a bit dissapointed not to get the new wrist heart rate Oxy-meter. PLEASE GARMIN I would really love an HRV tracking the wearables all day! I know you have some applications that help track the HRM but only when you activate them and have to stand still for 5 min like a “sick statistics freak” (which I am) but this should be automatic! Or give me a quick reminder every time I wake up to measure it?! Or why not measure it all the time? If you’re already measuring heart rate all day?

General Stats: (Taken from


Corning® Gorilla® Glass 3


stainless steel

QUICK RELEASE BANDS yes (20 mm, Industry standard)



42.5 x 42.5 x 13.5 mm

Fits wrists with a circumference of 127-204 mm

DISPLAY SIZE 1.2″ (30.4 mm) diameter
DISPLAY RESOLUTION 240 x 240 pixels
DISPLAY TYPE sunlight-visible, transflective memory-in-pixel (MIP)

41.8 g

BATTERY LIFE Smartwatch Mode: Up to 7 days
GPS mode: Up to 14 hours
MEMORY/HISTORY 200 hours of activity data

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