https://www.123articleonline.com/rss/author/403226/fourth-frontierArticles written by Fourth Frontier from 123ArticleOnline.comen-usCopyright (c) 123ArticleOnline.com All rights reserved. https://www.123articleonline.com/articles/1413056/the-importance-of-monitoring-heart-rate-variability-in-athletes Frontier X2 is the world's first and only smart heart monitor that provides real-time ECG. Improve your heart health with real-time feedback anytime, anywhere.