Your Fitbit device recognizes and awards active minutes when the activity you're doing is more strenuous than regular walking, which includes everything from a brisk walk to a cardio workout or run.
How do I earn active minutes?
Fitbit devices calculate active minutes using metabolic equivalents (METs). METs help measure the energy expenditure of various activities. Because they do so in a comparable way among persons of different weights, METs are widely used as indicators for exercise intensity. For example, a MET of 1 indicates a body at rest. Fitbit devices estimate your MET value in any given minute by calculating the intensity of your activity.
You earn active minutes for activities at or above about 3 METs. To stay in line with the Center for Disease Control's (CDC’s) “10 minutes at a time is fine” concept, minutes are only awarded after 10 minutes of continuous moderate-to-intense activity. You can view the CDC’s recommendations on the CDC website.
If the same activity gives you active minutes one day and fewer active minutes the next day, remember that the intensity of exercise is key. Often what seems like the exact same amount of effort over the same distance in fact differs slightly enough to change your active minutes total.
Do I earn active minutes if I manually log an exercise or activity?
For most manually logged activities, Fitbit uses a standard MET score and your (optional) calorie burn to calculate active minutes. High calorie burn activities award more active minutes. Since custom activities don't have a MET score associated, you'll only get active minutes for them if you also log a high calorie burn.
How do I achieve my active minute goal?
By default, you are given a starting goal of 30 active minutes a day based on the CDC recommendation of 20-30 minutes of daily moderate-to-intense activity. You can always change your active minutes goal to meet your personal needs. For information on how to change your goals, see How do I track my health and fitness goals with Fitbit?
Fitbit devices that track your heart rate do a better job of recognizing active minutes for non-step-based activities, such as weight lifting, strenuous yoga, and rowing. If your device doesn't have a heart rate sensor, your active minutes will be lower for non-step based activities.
The more calories you burn the higher your MET value, so therefore the more calories you burn the higher your total active minutes. Assuming you're active for at least 10 minutes at a time, green spikes on your calorie graph typically indicate that you’re earning active minutes.