However, one of the most commonly tracked metrics \u2014 calories burned \u2014 may not be completely accurate, especially for one group of people.<\/p>\n
![\"A](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/09\/checking-results-side-view-beautiful-142031294.jpg\")
Smartwatches are often used to track fitness information, but the tiny wrist computers may not be entirely accurate. Friends Stock \u2013 stock.adobe.com<\/p>\n
A study<\/a> from Florida International University\u2019s Medical Photonics Laboratory tracked 58 men and women of various ages and body weights who simultaneously wore smartwatches from Apple, Garmin, Samsung and Fitbit.<\/p>\n Participants alternated between two minutes of fast pedaling and five minutes of rest on a recumbent bicycle for 10 minutes, while researchers monitored their energy expenditure with a metabolic analyzer face mask.<\/p>\n Researchers then compared how many calories recorded by the watches with measurements from the masks, which are considered the most reliable way to measure calorie expenditure.<\/p>\n All four watches recorded substantial errors in calorie tracking, ranging from 15% to 25% compared with the lab measurements. The smartwatch estimates were least accurate in participants with body fat percentage above 35%.<\/p>\n Three of the brands overestimated how many calories the wearers burned, with Apple having the smallest average error, while Garmin and Samsung produced larger overestimates.<\/p>\n While Fitbit\u2019s measurement errors weren\u2019t consistently positive or negative compared with the lab readings, a different problem arose.<\/p>\n That wearable produced several implausible estimates, including multiple measurements that exceeded 450% of the metabolic system\u2019s readings.<\/p>\n Despite the errors across all four smartwatches, the researchers weren\u2019t surprised by the findings, as previous studies<\/a> have found similar inaccuracies.<\/p>\n What stood out most was the strong relationship between calorie-tracking error and body fat percentage.<\/p>\n As the body fat percentage of each wearer increased, the watches\u2019 measurements of calories burned became more inaccurate, ranging from 50% to 100% or more.<\/p>\n For example, if the metabolic analyzer measured an energy expenditure of 100 calories, a watch with a 50% overestimate would display 150 calories burned. A 100% overestimate would double the calories.<\/p>\n Researchers aren\u2019t entirely sure why body fat played such a role in calorie measurement, but they have a theory based on how the watches and their calorie-burning estimation algorithms were developed.<\/p>\n These types of watches use accelerometers<\/a> to measure movement and light-based sensors to estimate heart rate.<\/p>\n The data from these sensors is combined with age, sex, height and weight and fed into an algorithm that estimates how much energy a person expended.<\/p>\n The watches\u2019 caloric algorithms were made using data from leaner people, so increased soft-tissue motion at the wrist, combined with limited ranges for calorie data, may be more likely to produce errors.<\/p>\n The researchers also emphasized that while 50 calories may not seem like much, these differences can add up over time, resulting in thousands of calorie being miscounted.<\/p>\n Instead of tossing your smartwatch, exercise scientist and study author Jason Kostrna suggests treating the calorie tracker as an estimate rather than an exact measurement.<\/p>\n \u201cIf your goal is to lose weight, I would be conservative about using that number to determine how much to eat or to evaluate the success of a workout,\u201d Kostrna wrote in an article for The Conversation<\/a>.<\/p>\n A companion study<\/a> from Kostrna also found that heart rate measurements<\/a> from watches were accurate and that wearables may provide useful information for other metrics, like distance and pace while walking, running or biking.<\/p>\n","protected":false},"excerpt":{"rendered":"Sleek smartwatches are all the rage these days. Nearly 4 in 10 US adults wear them to track…\n","protected":false},"author":2,"featured_media":632792,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[46455,1348,499,203,103,61,60,5065,1855,80,239021],"class_list":["post-632791","post","type-post","status-publish","format-standard","has-post-thumbnail","category-gadgets","tag-calories","tag-exercise","tag-fitness","tag-gadgets","tag-health","tag-ie","tag-ireland","tag-smartwatches","tag-study-says","tag-technology","tag-trackers"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/632791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=632791"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/632791\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/632792"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=632791"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=632791"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=632791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"A](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/09\/142031300.jpg\")
Four brands of smartwatches were inaccurate in estimating calories burned, especially in those with high body fat. adrian_ilie825 \u2013 stock.adobe.com<\/p>\n