So if you demand medical-level accuracy either buy a chest strap or check your pulse using your fingers (! Wrist-based optical heart-rate monitors like that found on the Fitbit Charge 2 might not be as accurate but will certainly give you an indication of how your exercise is pushing your heart, and that's fine for most casual athletes.
The Charge 2 can also measure your Cardio Fitness Level, which gives a score as an estimation of your VO2 Max (the maximum amount of oxygen your body can use when you’re working out at your hardest).
And like the Alta, the main body is metal so it's tougher but sadly not waterproof (it is water resistant, so fine in the rain or a particularly sweaty gym session or run).
The heart is a muscle, so the more aerobic exercise you do, the stronger it becomes.
The fitter you are, the lower your resting heart rate will be.
This might sound a lot (and don't forget to check out the prices shown at the end of this review for the best available now) to pay for a tracker, but, believe me, you will quickly save that money back through walking more and catching buses, taxis and trains less, or just leaving the car back at home.
I worked out that I saved the price of my first activity tracker within about two and a half months.
Check out the best online prices at the top and bottom of this review or click here to view today's best prices on Amazon track Steps, Distance, Calories Burned, Active Minutes and Hourly Activity, plus Sleep Duration and quality. Pushing yourself to take the stairs rather than the lift or escalator, or running uphill rather than on the flat is a great way to increase your heart rate and burn more calories.
allows users to track workout intensity and calorie burn, and see the results via interactive charts and graphs on the app and Fitbit dashboard.
A quick-glance gauge allows you to adjust your intensity on the fly for a precision workout.
Heart-rate monitoring works well with the new Experts now believe that 60-80 beats per minute (bpm) is a healthy level.
The optimum Cardio zone is at 70-84 percent of maximum heart rate, and is the medium- to high-intensity exercise zone.
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.
Your heart rate can change as you get older, but it can also indicate a change to your health.