A recent scientific study has revealed that the calorie burn estimates provided by smartwatches can be inaccurate, with some devices overestimating or underestimating the number of calories burned by as much as 25%. This means that if a watch says you burned 300 calories during a workout, the actual number could be as low as 225 or as high as 375. These discrepancies could affect how people track their fitness progress or manage their diets. The study compared several popular smartwatch brands, including Apple, Fitbit, Samsung, and Garmin. Among these, Apple's devices were found to be the most accurate in estimating calorie burn. However, even the most accurate devices still had some level of error, which the researchers say could impact the reliability of fitness tracking for users. Fitness trackers use a combination of sensors, such as accelerometers and heart rate monitors, to estimate how many calories a person burns during physical activity. These sensors measure movement and heart rate, and then use algorithms to estimate calorie expenditure. However, the study found that the algorithms used by different manufacturers can yield widely varying results. The researchers suggest that users should be cautious when relying solely on smartwatch estimates for fitness tracking. They recommend using these devices as a general guide rather than an exact measure. For more accurate tracking, combining smartwatch data with other methods, such as food logging or professional fitness assessments, may be more effective.