{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T14:09:29Z","timestamp":1788962969903,"version":"build-2803163510"},"reference-count":34,"publisher":"JMIR Publications Inc.","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JMIR Mhealth Uhealth"],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>During flight, G force compels blood to stay in leg muscles and reduces blood flow to the heart. Cardiovascular responses activated by the autonomic nerve system and strengthened by anti-G straining maneuvers can alleviate the challenges faced during G loading. To our knowledge, no definite cardiac information measured using a mobile health device exists for analyzing G tolerance. However, our previous study developed the cardiac force index (CFI) for analyzing the G tolerance of military aircrew.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>This study used the CFI to verify participants\u2019 cardiac performance when walking and obtained a formula for predicting an individual\u2019s G tolerance during centrifuge training.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Participants from an air force aircrew undertook high-G training from January 2020 to December 2022. Their heart rate (HR) in beats per minute and activity level per second were recorded using the wearable BioHarness 3.0 device. The CFI was computed using the following formula: weight \u00d7 activity \/ HR during resting or walking. Relaxed G tolerance (RGT) and straining G tolerance (SGT) were assessed at a slowly increasing rate of G loading (0.1 G\/s) during training. Other demographic factors were included in the multivariate regression to generate a model for predicting G tolerance from the CFI.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 213 eligible trainees from a military aircrew were recruited. The average age was 25.61 (SD 3.66) years, and 13.1% (28\/213) of the participants were women. The mean resting CFI and walking CFI (WCFI) were 0.016 (SD 0.001) and 0.141 (SD 0.037) kg \u00d7 G\/beats per minute, respectively. The models for predicting RGT and SGT were as follows: RGT = 0.066 \u00d7 age + 0.043 \u00d7 (WCFI \u00d7 100) \u2013 0.037 \u00d7 height + 0.015 \u00d7 systolic blood pressure \u2013 0.010 \u00d7 HR + 7.724 and SGT = 0.103 \u00d7 (WCFI \u00d7 100) \u2212 0.069 \u00d7 height + 0.018 \u00d7 systolic blood pressure + 15.899. Thus, the WCFI is a positive factor for predicting the RGT and SGT before centrifuge training.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The WCFI is a vital component of the formula for estimating G tolerance prior to training. The WCFI can be used to monitor physiological conditions against G stress.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.2196\/48812","type":"journal-article","created":{"date-parts":[[2023,7,26]],"date-time":"2023-07-26T10:31:38Z","timestamp":1690367498000},"page":"e48812","source":"Crossref","is-referenced-by-count":8,"title":["G Tolerance Prediction Model Using Mobile Device\u2013Measured Cardiac Force Index for Military Aircrew: Observational Study"],"prefix":"10.2196","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8423-7168","authenticated-orcid":false,"given":"Ming-Hao","family":"Kuo","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6813-2419","authenticated-orcid":false,"given":"You-Jin","family":"Lin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-1375-3772","authenticated-orcid":false,"given":"Wun-Wei","family":"Huang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5199-3526","authenticated-orcid":false,"given":"Kwo-Tsao","family":"Chiang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2723-9372","authenticated-orcid":false,"given":"Min-Yu","family":"Tu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8563-1378","authenticated-orcid":false,"given":"Chi-Ming","family":"Chu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7524-3010","authenticated-orcid":false,"given":"Chung-Yu","family":"Lai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1010","published-online":{"date-parts":[[2023,7,26]]},"reference":[{"issue":"5","key":"ref1","first-page":"496","volume":"76","author":"Rickards, CA","year":"2005","journal-title":"Aviat Space Environ Med"},{"issue":"7","key":"ref2","first-page":"709","volume":"70","author":"Yilmaz, U","year":"1999","journal-title":"Aviat Space Environ Med"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.7205\/milmed-d-11-00003"},{"key":"ref4","first-page":"122","author":"Burton, R","year":"2002","journal-title":"Fundamentals of Aerospace Medicine. 3rd ed"},{"key":"ref5","first-page":"39","author":"Newman, DG","year":"2016","journal-title":"High G Flight: Physiological Effects and Countermeasures. 1st ed"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.3357\/asem.3200.2012"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-020-78687-3"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.3357\/AMHP.5323.2019"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph17218061"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.3357\/AMHP.4032.2015"},{"issue":"2","key":"ref11","first-page":"128","volume":"62","author":"Webb, JT","year":"1991","journal-title":"Aviat Space Environ Med"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.3390\/ijerph18168832"},{"key":"ref13","unstructured":"ChuCMethod for detecting cardiac status, method for monitoring cardiac status during exercise, and apparatus for monitoring cardiac status. 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