Smartphone-Derived Heart-Rate Variability and Training Load in a Women's Soccer Team

Int J Sports Physiol Perform. 2015 Nov;10(8):994-1000. doi: 10.1123/ijspp.2014-0556. Epub 2015 Mar 10.


Purpose: This study evaluated the 7-d mean and coefficient of variation (CV) of supine and standing ultrashort log-transformed root mean square of successive R-R intervals multiplied by 20 (lnRMSSDx20) obtained with a smartphone application (app) in response to varying weekly training load (TL). In addition, the authors aimed to determine if these values could be accurately assessed in as few as 5 or 3 d/wk.

Methods: Nine women from a college soccer team performed daily heart-rate-variability measures with an app in supine and standing positions over 3 wk of moderate, high, and low TL. The mean and CV over 7, 5, and 3 d were compared within and between weeks.

Results: The 5- and 3-d measures within each week provided very good to nearly perfect intraclass correlations (ICCs .74-.99) with typical errors ranging from 0.64 to 5.65 when compared with the 7-d criteria. The 7, 5, and 3-d supine CV and the 7-day standing CV were moderately lower during the low-load than the high-load week (P .003-.045, effect sizes 0.86-0.92), with no significant changes occurring in the other measures.

Conclusion: This study supports the use of the mean and CV of lnRMSSD measured across at least 5 d for reflecting weekly values. The supine lnRMSSDx20 CV as measured across 7, 5, and 3 d was the most sensitive marker to the changes in TL in the 3-wk period.

MeSH terms

  • Female
  • Heart Rate / physiology*
  • Humans
  • Monitoring, Ambulatory / methods*
  • Perception / physiology
  • Physical Education and Training*
  • Physical Exertion / physiology
  • Posture
  • Smartphone*
  • Soccer / physiology*
  • Supine Position
  • Young Adult