Please read Why Max Heart rate is important to know before reading this.

‍

The notion of activity intensity is highly correlated to your Maximum Heart Rate (MHR), the fastest rate at which your heart can beat in one minute as it is based upon a percentage of your MHR. 

‍

‍

Circular divides intensity in three levels:

• Low-intensity activity → from 40% to 55% of your MHR
• Medium-intensity activity → from 55% to 75% of your MHR 
• High-intensity activity → from 75% to 90% of your MHR

Low-intensity activity

This the activity you do perform during your daily routine. When you are at a low-intensity level, you are able to breathe normally. Under normal conditions, low-intensity exercise will not make you sweat. Examples might include taking an easy walk, easy dancing, stretching or shopping.

Medium intensity activity

With a medium-intensity level, you breathe harder and deeper than at a sedentary level. After around 10 minutes of exercise, you should break into a sweat. Riding a bike on flat surfaces, brisk walking, jogging, endurance exercises and playing doubles tennis are examples of medium intensity activity.

High-intensity activity

At a vigorous level of exercise, your heart is working at maximum efficiency. Talking will be difficult at this level and you will breathe rapidly. You will break into a sweat after just a few minutes doing exercises like biking or hiking on hills, swimming laps, playing basketball, boxing or doing high-intensity aerobics like HIIT program.

Some research showed that if you get more than 12 minutes of 85 percent of your maximum heart rate in a workout you’ll keep burning 15% more calories even after you stop working out as afterburning during the next 24 hours.‍

‍

Knowing how we define physical activity intensity, we explain How Circular tracks your activity volume.