{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,28]],"date-time":"2026-02-28T08:46:38Z","timestamp":1772268398465,"version":"3.50.1"},"reference-count":43,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T00:00:00Z","timestamp":1666656000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Program of Physiology, Faculty of Science"},{"name":"Graduate School Dissertation Funding for Thesis"},{"name":"Revenue Budget Fund from Prince of Songkla University"},{"name":"Educational Institutions Scholarship for Outstanding GPA"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Kratom is a psychoactive plant used to enhance productivity among laborers in Southeast Asian countries. Previous findings from\n                      <jats:italic>in vitro<\/jats:italic>\n                      research of mitragynine, a major component of kratom, suggested a possible risk of heart function abnormality. However, the cardiac autonomic function in long-term kratom users with chewing forms has never been studied. This study aimed to investigate heart rate variability (HRV) indices of cardiac autonomic function in long-term kratom chewers (LKC), compared to the control levels, and also to examine the correlation between HRV indices and relevant kratom use factors.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Method<\/jats:title>\n                    <jats:p>\n                      A total number of 50 participants consisted of LKC (\n                      <jats:italic>n<\/jats:italic>\n                      = 31) who regularly chewed fresh kratom leaves for at least 2 years and demographically matched control subjects (\n                      <jats:italic>n<\/jats:italic>\n                      = 19). Resting electrocardiogram (ECG) signals were recorded from subjects for 3 min to analyze the ultrashort HRV in the frequency domain. The normalized low frequency (LFn) and high frequency (HFn) were chosen to be the HRV indices to evaluate cardiac autonomic function. The comparison of HRV indices between groups and the correlation between HRV indices and duration and quantity of kratom use was further conducted in statistical analysis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The LKC significantly increased LFn together with enhanced HFn compared to the control group tested, indicating that LKC changed cardiac autonomic function with parasympathetic dominance. Furthermore, no significant correlation between the HRV indices and the duration and quantity of kratom use was found, suggesting that the HRV indices were not relevant to these factors. The present study provided scientific-based evidence of cardiac autonomic modulation in long-term kratom chewers. LFn and HFn may be promising cardiac autonomic indicators for monitoring health outcomes in LKC.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.7717\/peerj.14280","type":"journal-article","created":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T03:26:01Z","timestamp":1666668361000},"page":"e14280","source":"Crossref","is-referenced-by-count":5,"title":["Exploring of cardiac autonomic activity with heart rate variability in long-term kratom (\n                    <i>Mitragyna speciosa<\/i>\n                    Korth.) users: a preliminary study"],"prefix":"10.7717","volume":"10","author":[{"given":"Wanumaidah","family":"Saengmolee","sequence":"first","affiliation":[{"name":"Biosignal Research Center for Health, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand"},{"name":"Physiological Program, Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand"},{"name":"Bio-Inspired Robotics and Neural Engineering (BRAIN) Laboratory, School of Information Science and Technology (IST), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dania","family":"Cheaha","sequence":"additional","affiliation":[{"name":"Biosignal Research Center for Health, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand"},{"name":"Biology Program, Division of Biological Science, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nusaib","family":"Sa-ih","sequence":"additional","affiliation":[{"name":"Biosignal Research Center for Health, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, Thailand"},{"name":"Physiological Program, Division of Health and Applied Sciences, Faculty of Science, Prince of Songkla University, Hatyai, Songkhla, 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