Shortening the heart rate variability analysis window to 2 minutes is reliable for RMSSD, but a full 4-minute window is required for accurate measurement of low-frequency and total power.
Observational (n=3)
No
Does a shortened recording window provide reliable HRV measurements compared to a standard 4-minute window in elite athletes?
HRV analysis windows can be shortened to 2 minutes for RMSSD, but 4 minutes are required for reliable low-frequency and total power measurements in athletes.
Heart rate variability (HRV) is non-invasive and commonly used for monitoring responses to training loads, fitness, or overreaching in athletes. Yet, the recording duration for a series of RR-intervals varies from 1 to 15 min in the literature. The aim of the present work was to assess the minimum record duration to obtain reliable HRV results. RR-intervals from 159 orthostatic tests (7 min supine, SU, followed by 6 min standing, ST) were analyzed. Reference windows were 4 min in SU (min 3-7) and 4 min in ST (min 9-13). Those windows were subsequently divided and the analyses were repeated on eight different fractioned windows: the first min (0-1), the second min (1-2), the third min (2-3), the fourth min (3-4), the first 2 min (0-2), the last 2 min (2-4), the first 3 min (0-3), and the last 3 min (1-4). Correlation and Bland & Altman statistical analyses were systematically performed. The analysis window could be shortened to 0-2 instead of 0-4 for RMSSD only, whereas the 4-min window was necessary for LF and total power. Since there is a need for 1 min of baseline to obtain a steady signal prior the analysis window, we conclude that studies relying on RMSSD may shorten the windows to 3 min (= 1+2) in SU or seated position only and to 6 min (= 1+2 min SU plus 1+2 min ST) if there is an orthostatic test. Studies relying on time- and frequency-domain parameters need a minimum of 5 min (= 1+4) min SU or seated position only but require 10 min (= 1+4 min SU plus 1+4 min ST) for the orthostatic test.
Bourdillon et al. (Thu,) conducted a observational in Elite athletes (n=3). Shortened HRV recording windows (1-3 minutes) vs. Standard 4-minute recording window was evaluated on Reliability of HRV parameters (RMSSD, LF, HF, total power) in shortened windows vs 4-min reference window. Shortening the heart rate variability analysis window to 2 minutes is reliable for RMSSD, but a full 4-minute window is required for accurate measurement of low-frequency and total power.