A1 Journal article (refereed)
Reliability and Sensitivity of Nocturnal Heart Rate and Heart-Rate Variability in Monitoring Individual Responses to Training Load (2022)

Nuuttila, O.-P., Seipäjärvi, S., Kyröläinen, H., & Nummela, A. (2022). Reliability and Sensitivity of Nocturnal Heart Rate and Heart-Rate Variability in Monitoring Individual Responses to Training Load. International Journal of Sports Physiology and Performance, 17(8), 1296-1303. https://doi.org/10.1123/ijspp.2022-0145

JYU authors or editors

Nuuttila, Olli-Pekka
Seipäjärvi, Santtu
Kyröläinen, Heikki

Publication details

All authors or editors: Nuuttila, Olli-Pekka; Seipäjärvi, Santtu; Kyröläinen, Heikki; Nummela, Ari

Journal or series: International Journal of Sports Physiology and Performance

ISSN: 1555-0265

eISSN: 1555-0273

Publication year: 2022

Publication date: 06/07/2022

Volume: 17

Issue number: 8

Pages range: 1296-1303

Publisher: Human Kinetics

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1123/ijspp.2022-0145

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/82763

Abstract

Purpose: To assess the reliability of nocturnal heart rate (HR) and HR variability (HRV) and to analyze the sensitivity of these markers to maximal endurance exercise. Methods: Recreational runners recorded nocturnal HR and HRV on nights after 2 identical low-intensity training sessions (n = 15) and on nights before and after a 3000-m running test (n = 23). Average HR, the natural logarithm of the root mean square of successive differences (LnRMSSD), and the natural logarithm of the high-frequency power (LnHF) were analyzed from a full night (FULL), a 4-hour (4H) segment starting 30 minutes after going to sleep, and morning value (MOR) based on the endpoint of the linear fit through all 5-minute averages during the night. Differences between the nights were analyzed with a general linear model, and intraclass correlation coefficient (ICC) was used for internight reliability assessments. Results: All indices were similar between the nights followed by low-intensity training sessions. A very high ICC (P < .001) was observed in all analysis segments with a range of .97 to .98 for HR, .92 to .97 for LnRMSSD, and .91 to .96 for LnHF. HR increased (P < .001), whereas LnRMSSD (P < .01) and LnHF (P < .05) decreased after the 3000-m test compared with previous night only in 4H and FULL. Increments in HR (P < .01) and decrements in LnRMSSD (P < .05) were greater in 4H compared with FULL and MOR. Conclusions: Nocturnal HR and HRV indices are highly reliable. Demanding maximal exercise increases HR and decreases HRV most systematically in 4H and FULL segments.

Keywords: endurance training; pulse; recovery (return); autonomic nervous system; measuring methods; reliability (general)

Free keywords: endurance training; recovery; recovery monitoring; autonomic nervous system; parasympathetic nervous system

Fields of science: