{"doi":"10.1093/gerona/glae120","title":"Need to Revise Classification of Physical Activity Intensity in Older Adults? The Use of Estimated METs, Measured METs, and <i>VO</i>2 Reserve","abstract":"BACKGROUND: Multiples of resting metabolic rate (RMR) are often used to classify physical activity intensity, a concept known as the metabolic equivalent of task (MET). However, the METs metrics may misclassify physical activity intensity in older adults because of age-related changes in RMR and maximal aerobic capacity (V˙O2max). This study aimed to (i) compare classifications of activity intensity by estimated (METsestimated) and measured (METsmeasured) METs and (ii) compare physical activity classified by absolute (METsmeasured) versus relative intensity (%V˙O2Reserve) in older adults. METHODS: Ninety-eight adults aged 75-90 years participated in the study. RMR and V˙O2 during sitting, standing, daily activities, and 6-minute walking test were measured. V˙O2Reserve was defined as the difference between V˙O2max and RMR. Moderate and vigorous intensity was classified as 3 and 6 METs and 40% and 60% of V˙O2Reserve, respectively. Paired t tests and a confusion matrix were used to investigate aims 1 and 2, respectively. RESULTS: METsmeasured was 24% lower than the standard 1 MET of 3.5 mL O2·min-1·kg-1. METsestimated underestimated the intensity during daily and walking activities when compared to METsmeasured. Nevertheless, when comparing METsmeasured to percentages of V˙O2Reserve, a mismatch was shown for moderate intensity in 47%-67% of the participants during daily activities and 21% of the participants during self-selected gait speed. CONCLUSIONS: Applying METsestimated for older adults leads to potential underestimation of physical activity intensity, suggesting that current classification metrics should be revised for older adults. V˙O2Reserve is a candidate metric for establishing precise physical activity intensity cut points for older adults. Clinical Trials Registration Number: NCT04821713.","journal":"The Journals of Gerontology Series A","year":2024,"id":435211,"datarank":0.5433731632394784,"base_score":2.5649493574615367,"endowment":2.5649493574615367,"self_citation_contribution":0.38474240361923057,"citation_network_contribution":0.15863075962024778,"self_endowment_contribution":0.38474240361923057,"citer_contribution":0.15863075962024778,"corpus_percentile":null,"corpus_rank":null,"citation_count":12,"citer_count":10,"citers_with_citation_signal":6,"citers_with_endowment":6,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9505,"is_data_producer":true,"deposit_databanks":{"ClinicalTrials.gov":["NCT04821713"]},"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1081814,"name":"Mark A. Tully","orcid":"0000-0001-9710-4014","position":1,"is_corresponding":false},{"id":1120953,"name":"Li‐Tang Tsai","orcid":"0000-0001-6571-3376","position":2,"is_corresponding":false},{"id":558940,"name":"Kasper Degn Gejl","orcid":"0000-0001-9350-7879","position":3,"is_corresponding":false},{"id":558939,"name":"Niels Ørtenblad","orcid":"0000-0001-9060-4139","position":4,"is_corresponding":false},{"id":1242379,"name":"Kurt Jensen","orcid":"0000-0001-9014-2093","position":5,"is_corresponding":false},{"id":6534,"name":"Annemarie Koster","orcid":"0000-0003-1583-7391","position":6,"is_corresponding":false},{"id":19240,"name":"Marjolein Visser","orcid":"0000-0002-5136-298X","position":7,"is_corresponding":false},{"id":270849,"name":"Marianne Andersen","orcid":"0000-0002-4603-9504","position":8,"is_corresponding":false},{"id":341574,"name":"Paolo Caserotti","orcid":"0000-0002-0476-5786","position":9,"is_corresponding":false},{"id":1242858,"name":"Mathias Skjødt","orcid":null,"position":0,"is_corresponding":true}],"reference_count":49,"raw_metadata":null,"created_at":"2026-07-19T02:00:03.406367Z","pmid":"38703071","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}