If you ride a recumbent bike, the armband may believe you are doing something else like sitting. You can try moving your arms more during the ride. Although it’s not typical, the exerspy can misjudge biking (on any type of bike).
Tips for using exerspy while biking
When riding a road bike, check that the armband is worn in its normal position, on the upper left arm, with the armband closer to the shoulder than the elbow, at the back of the arm.
When riding an exercise bike, also called a stationary bike, some people may feel they deserve more calories than the armband gives them credit for. This might be because of the exercise bike's geometry and handle bar style. In this case, when riding the exercise bike, try this:
- Wear the armband lower on the arm, closer to the elbow than the shoulder, and
- Rotate the armband a little to the outside of your arm. (With your arm hanging at your side, palms facing your legs - not sitting on the bike or holding the handle bars - the armband would be in line with your wrist watch.
- When you have finished riding the bike, pull the armband back to its normal position.
More info
Keep in mind that generally if the armband underestimates a certain type of exercise, it will have a minor effect on one’s entire week. For instance, if the armband underestimates a stationary bike by 5 cals/min and you ride it for 30 minutes 5 days/week it would underestimate your weekly total by 750 calories or a little over 100 calories/day, which as you know would be fairly minor error in the weekly picture.
The moral of the story is to always follow the deficit number, and make your adjustments to that number. That way you never have to worry about pinpointing energy expenditure or food logging accuracy--simply eat less to lose by reducing something you were eating previously and/or move more by using whatever calorie burn number the armband showed you averaged last week and increasing it by whatever calories necessary to stay on goal.
You can also use the off-body feature to input those calories burned and there is an option for various types of stationary biking. This way you don't have to miss out on recording that information.