Abstract
Background
Frailty is often experienced by older adults, which can lead to long-term health problems. We aimed to examine associations with improvements in nutritional status, sarcopenia (age-related loss of skeletal muscle mass and strength), and frailty in four groups with different oral exercise frequencies.
Methods
We conducted a prospective, parallel multi-arm randomized controlled trial (Japan Registry of Clinical Trials (jRCT) 1062210063) to test the effects of oral exercise on frailty in older adults. Each intervention consisted of a standardized oral exercise protocol including neck exercises, lip exercises, and tongue movements, designed to improve oral function and reduce frailty. The primary outcome was the change in the number of frailty criteria from baseline to follow-up. Individuals aged ≥60 years were screened for frailty status using standardized criteria at the Department of Preventive Dentistry at Okayama University Hospital between October 2022 and December 2023. Those identified as pre-frailty or frailty were eligible and enrolled in the study. After screening 60 individuals, 58 eligible participants were randomly assigned using block randomization to one of four oral exercise frequency groups: 3 times/day & everyday, 3 times/day & 3 days/week, once/day & everyday, and once/day & 3 days/week. A two-way repeated measures analysis of variance was used to evaluate the impact of the four frequencies of oral exercise methods on frailty in older adults. Outcome assessors were blinded; participants were not.
Results
Here we show the results of the 58 participants. Group sizes are: 3 times/day & everyday (n = 14), 3 times/day & 3 days/week (n = 15), once/day & everyday (n = 14), once/day & 3 days/week (n = 15). The trial is completed as planned, and all randomized participants are analyzed. The main effect of time is significant for the number of frailty criteria (F = 14.803, p < 0.001, partial eta squared = 0.215). The mean changes from baseline to follow-up are −0.357 (95% Confidence Interval −0.787 to 0.073) in the 3 times/day & everyday group, −0.600 (95% Confidence Interval −1.255 to 0.055) in the 3 times/day & 3 days/week group, −0.571 (95% Confidence Interval −1.379 to 0.236) in the once/day & everyday group, and −0.600 (95% Confidence Interval −1.008 to −0.192) in the once/day & 3 days/week group. The main effect of time is also significant for the number of oral hypofunction criteria (F = 16.456, p < 0.001, partial eta squared = 0.234). No important adverse events or side effects related to the intervention were observed.
Conclusions
After conducting oral exercises for 3 months on older adults with pre-frailty or frailty, improvements in frailty are observed. Overall, these exercises could be a simple, low-cost way to support healthy aging in the community.
Plain language summary
Older adults often experience frailty, which can lead to health problems and reduced independence. This study tested whether simple oral exercises, such as moving the tongue and cheeks, can help improve frailty. We randomly assigned 58 older adults with frailty to four groups that performed oral exercises at different frequencies for three months. We found that frailty scores improved in all groups, and the most practical and effective schedule was three times a day, three days a week. These exercises are easy to do at home and may help older adults maintain better health and quality of life. This approach could be a simple, low-cost way to support healthy aging in the community.
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Data availability
Due to the study protocol approved by the ethics committee, which specifies that participant data will not be reused for secondary purposes, anonymized individual-level data cannot be shared beyond what is presented in this article. All aggregated results are included in the figures and tables within the manuscript, and the numerical source data underlying the tables are provided in Supplementary Data 1. The study protocol is publicly available at the Japan Registry of Clinical Trials (jRCT1062210063).
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Acknowledgements
This work was supported by a KAKEN Grant-in-Aid from the Japan Society for the Promotion of Science (21K10208). This research did not receive any other specific grants from funding agencies in commercial or not-for-profit sectors. The authors thank FORTE Science Communications (https://www.forte-science.co.jp/) for English language editing.
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N.T.: Conceptualization, Methodology, Data curation, Formal analysis, Writing—original draft, Visualization, Project administration, Funding acquisition. N.S.: Data curation, Investigation, Writing—review and editing, Visualization. S.I.: Data curation, Investigation, Writing—review and editing. M.M.: Conceptualization, Methodology, Formal analysis, Writing—review and editing. D.E.: Conceptualization, Methodology, Formal analysis, Writing—review and editing. All authors read and approved the final manuscript.
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Communications Medicine thanks Erich J. Greene, Tao Chen and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. A peer review file is available.
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Takeuchi, N., Sawada, N., Inada, S. et al. Effects of an oral exercise intervention on pre-frailty or frailty in older people: a randomized clinical trial. Commun Med (2026). https://doi.org/10.1038/s43856-025-01361-0
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DOI: https://doi.org/10.1038/s43856-025-01361-0
