Fitbit released two new activity trackers in early 2015. The Fitbit Charge HR and Fitbit Surge both feature heart-rate monitors plus a bunch of other fitness and activity-tracking features. See all Activity Tracker Reviews.
The Fitbit Charge HR is a more advanced version of the Fitbit Charge, which was released in November 2014. The Fitbit Surge features even more features for the performance-obsessed fitness fanatics. As such the Charge HR should appeal to someone wanting more advanced activity-tracking stats than a Fitbit Flex or Charge user – particularly heart-rate monitoring – but not to the level and price as the more sports-oriented Surge.
The Fitbit Charge HR also has some extra benefits, such as a watch-type buckle that is far more secure than the clasp on the Flex and Charge.
It features all the functions of the Charge and adds some compelling new monitors that will make many Charge buyers stop to consider paying the xtra £20 for the Charge HR’s extras.
Like the Charge the Charge HR is an activity-tracker wristband that displays fitness stats right there on your wrist – unlike many of its rivals, such as the Jawbone Up24, which don’t have such a real-time stats display on the band itself.
While the Charge costs £99.99, the Fitbit Charge HR is priced at £119.99. Spending that extra £20 is tempting because of the extra features the HR offers.
Bear in mind that no Fitbit tracker integrates with Apple Health, so your fitness data from the Fitbit app can't be imported into the Health app. However. this is no major problem since the Fitbit app presents the data nicely and lets you compete with friends.
Pictured from left: Fitbit Charge (Black), Fitbit Charge HR (Plum), and Fitbit Surge (Black).
Fitbit Charge HR vs Fitbit Charge: it’s all about heart rate
All Fitbits have a MEMS 3-axis accelerometer that measures motion patterns to determine your steps taken, distance travelled, active minutes, and calories burned. The Charge and Charge HR both include a clock so you can ditch the watch if you like, but many wear the fitness band alongside their wristwatch. For a full breakdown and comparison of all the Fitbits see our feature “Which Fitbit is Best”.
The Fitbit Charge and Charge HR also feature an altimeter (unlike the Apple Watch) that measures floors climbed, to push you to climb those stairs instead of taking the lift, or to take the uphill route to work rather than the easier flat. Every 10ft elevation you walk or climb is counted as one flight of stairs.
The Charge HR isn’t the multi-sports powerhouse that is the Fitbit Surge, but – as with the Charge – you can use it to log workouts and – via the app – see a monthly exercise plan. Fitbit sees it as for “Active” users, compared to the Charge that’s aimed at “Everyday” users. You might also be interested in Fitbit's Aria scales that sync with your account, and measure weight, body fat percentage and BMI; read our Fitbit Aria scales review.
Using Mobile Run both can track run, walk and hike stats and map routes using your iPhone’s GPS; the Surge has its own built-in GPS. These functions are not quite there on Android yet, unfortunately.
This is great for recording Average Pace and Split Paces. It also offers music controls so you can use it to select and shuffle songs on your iPhone. You can view runs from the past four weeks. You tap specific runs for an expanded view, where you can view steps, calories, and active minutes taken during your MobileRun.
Both wristbands also measure the duration and quality of your sleep, which is an often-forgotten aspect of leading a fit and healthy lifestyle. Sleep detection is now automatic. In the past you had to tap or push a button as you drifted off to the land of nod – which meant that this action was occasionally missed. This is another area where the Fitbits beat the battery-shy Apple Watch.
Both trackers feature a vibrating alarm to wake you – but not your partner – at the times you set beforehand.
If your phone is nearby you can set the Fitbit Charge and HR to show incoming call notifications using Caller ID. The top-of-the-range Fitbit Surge goes further yet, with built-in text notifications, music control and GPS tracking, so you don’t even need your phone nearby.
Fitbit Charge HR review: heart rate tracking
So far, so similar for the two Charges. What does the Fitbit Charge HR offer that’s missing from the Charge?
The Charge HR is designed for more active users than the Charge – gym regulars (but not nuts), joggers and the more dedicated keep fit people, rather than the moderate exerciser who’ll be happy with the Charge or entry-level Fitbit Flex.
The main difference between Charge and Charge HR, as pointed out rather obviously in the name, is the Charge HR’s heart-rate monitoring (shared by the Surge), which delivers continuous heart rate, and lets you see how you’re doing on the wristband as well as on the smartphone app. Unlike other heart-rate monitors it doesn’t require a device to be strapped to your chest. It’s all done on the wrist, which means you’ll get a more complete picture of your heart rate as it is on all day and night.
Charge HR features Fitbit’s proprietary PurePulse optical heart-rate technology, which uses safe LED lights on the underside of the wristband to detect blood volume and capillary-size changes under pressure.
When your heart beats, your capillaries expand and contract based on blood volume changes. PurePulse LED lights on the Charge HR – and Fitbit Surge – reflect onto the skin to detect blood volume changes.
Fitbit says that the LED lights are safe for skin and are on the visible spectrum, similar to the domestic house lights. They are very low power so will not burn the skin, and are programmed to shut down if your device freezes or doesn’t see the right signal.
PurePulse allows users to track workout intensity and calorie burn with algorithms that provide insight through interactive charts and graphs on the app and Fitbit dashboard.
The heart-rate icon on the Charge HR display tells you if you're in one of three heart-rate zones. These zones can help you optimize your workout by targeting different training intensities, and are calculated based on a percentage of your estimated maximum heart rate.
Fitbit calculates your max heart rate with the common formula of 220 minus your age. When you’re “out of zone” – that is below 50 percent of your maximum heart rate – your heart rate may still be elevated but not enough to be considered exercise.
During low- to medium-intensity Fitbit classes this as the Fat Burn zone, measured at 50-69 percent of maximum heart rate. This is called the Fat Burn zone because a higher percentage of calories are burned from fat, but the total calorie burn rate is lower.
The optimum Cardio zone is at 70-84 percent of maximum heart rate, and is the medium- to high-intensity exercise zone. Fitbit describes this zone as when you are “pushing yourself but not straining”.
The Peak heart-rate zone is the high-intensity exercise zone for short intense sessions that improve performance and speed – it is greater than 85 percent of your maximum heart rate.
Instead of using the three default zones you can create a custom heart-rate zone on your computer’s Fitbit dashboard.
When you pair your Charge HR with the app you'll notice a new resting BPM field (new, that is, if you're upgrading from an older Fitbit). This will be populated once you've slept while wearing the wristband. Resting heart rate is traditionally measured just before waking up and certainly before you start moving around.
The Fitbit Charge HR (and Surge) go one better than most current activity trackers as they measure your heart rate - including your resting rate - throughout the day. The app graphs your resting heart rate so you can see how it changes from day to day, week to week and month to month. You can also examine your daily heart rate graph and see how long you spent in the three zones.
If you track workouts by pressing and holding the Charge HR's button to start and stop the stop watch, you'll also get workout summaries showing your heart rate and time spent in each zone for that activity. (Currently there are no on-device summaries beyond the stopwatch time, but Fitbit has just announced (1st March 2015) that a forthcoming firmware update which will include a full workout summary on-screen. This is what a cardio workout looks like in the iOS app:
Crucially, when compared to trackers with no heart rate monitor and those which only measure heart rate on demand, the Charge HR gives you a much more accurate calorie burn figure. Knowing your heart rate means the Charge HR knows the intensity of the exercise - a value missing in the equation when there's no heart rate data.
Also on the horizon is the Microsoft Band. Here's what we think of the Microsoft Band compared to the Charge HR.
Fitbit Charge HR vs Fitbit Charge: specs
The designs of the two wristbands are very similar. Comparing the two next to each other shows that the lesser-functioned Charge, strangely, is very slightly wider than the HR.
The Charge – not having to worry about tracking heart rate – boasts a much longer battery life of 7-10 days, compared to the HR’s 5+ days. When we have tested the Charge HR for longer we’ll update this review with our own battery test results.
Both are water resistant up to one Atmosphere, which theoretically means they can be submerged to 10 metres, but in reality it means each will withstand not much more than splashes and a quick dousing. Neither should be worn in the shower or when swimming. The Surge is more water resistant (five Atmosphere) than these two.
Fitbit Charge HR vs Fitbit Charge: design
While the two Charges look similar we much prefer the HR’s watch-like strap and buckle, which feel less likely to slip off. Fitbit has improved the Charge’s clasp, following complaints about the previous model Fitbit Force’s looser clasp, but the buckle is a real bonus for the HR. I’d go as far to say that it alone is worth the extra £20!
The Charge HR is available in four colours (see below): Black, Blue, Plum, and Tangerine.
The Charge (below) comes in Black, Blue, Slate and Burgundy.
Fitbit likes to think of the Charge for everyday users who want to get fitter and see how they are doing in real time on the wristband and also via the excellent free app and graphics-heavy desktop dashboard. The Charge HR user is more active and will get more data from the heart-rate monitoring – especially when used with the Peak, Cardio and Fat Burn Zones.
We think that the casual Charge user might very well be tempted by the heart-rate tracking, too, and as it’s only an extra £20 the only thing stopping the upgrade is the wait till next year. You also get the more secure watch-like buckle with the Charge HR.
We love the Surge for its GPS and more sports-based features but the Fitbit Charge HR is a welcome, minimal step below for the rest of us.
