Key result
Daily heart rate variability assessment showed a significant negative relationship with saliva T:C ratio (β = -0.218; 95% CI -0.391 to -0.044; p < 0.05) and 95% sensitivity for detecting changes.
Why the study?
The study was designed to determine the relationship between resting HRV and the testosterone to cortisol (T:C) ratio, and to evaluate the diagnostic ability of HRV to assess changes in T:C ratio during high-intensity functional training.
Does daily HRV assessment correlate with changes in testosterone-to-cortisol ratio in recreationally-active adults undergoing a 9-week high-intensity functional training intervention?
Observational (n=8)
Does daily HRV assessment correlate with changes in testosterone-to-cortisol ratio in recreationally-active adults undergoing a 9-week high-intensity functional training intervention?
Effect estimate: β = -0.218 (95% CI -0.391 to -0.044)
p-value: p=< 0.05
Daily HRV assessment demonstrates excellent sensitivity but poor specificity for detecting meaningful changes in testosterone-to-cortisol ratio during high-intensity functional training.
Should not yet change practice for monitoring training stress; leaves open validation of HRV as T:C surrogate in athletes.
International Journal of Exercise Science 14(3): 260-273, 2021. The study purpose was to determine the relationship of resting heart rate variability (HRV) and testosterone to cortisol (T:C) ratio, along with the diagnostic ability of HRV to assess changes in T:C ratio during a 9-week high-intensity functional training intervention. Eight recreationally-active men (n = 4, age 24.25 ± 1.75 yrs, height 181.25 ± 3.86 cm, weight 79.68 ± 11.66 kg) and women (n = 4, age 26 ± 3.6 yrs, height 164.25 ± 3.3, weight 73.4 ± 8.42) completed daily HRV measurements (HRVdaily) using photoplethysmography via a commercially-available smartphone application along with weekly saliva samples. Saliva samples were analyzed for concentrations of testosterone (T) and cortisol (C) via enzyme-linked immunosorbent assays. Upon study completion 72 data points were available, due to participant compliance and inadequate saliva sample, 67 matched pairs of HRV and T:C ratio were analyzed. A statistically significant negative relationship (n = 67, r = -.315, p < 0.05) was found between HRVdaily and saliva T:C ratio concentrations within aggregate data. Individual participant relationships showed considerable variability (r = - 0.101 – 0.665, p = 0.103 to 0.829 The model which best explained the data resulted in AIC = 130.247 with factors HRVdaily (β = -0.218, 95%CI = -0.391, -0.044, t = -2.46, p < 0.05), Sex (β = 0.450, 95%CI = -0.214, 1.114, t = 1.113, p = 0.242), and Group (β = -0.394, 95%CI = -1.089, 0.302, t = -1.11, p = 0.311). Diagnostically, HRVdaily demonstrates excellent sensitivity (95%), but poor specificity (5%) for detecting meaningful changes in T:C ratio. Assessment of HRVdaily may be a clinically valid proxy measure for monitoring hormonal changes throughout a training intervention.
No takes yet. Share an insight, caveat, or question.
DeBlauw et al. (2021) conducted an observational in Healthy recreationally-active adults (n=8). Daily heart rate variability (HRV) assessment was evaluated on Relationship between daily HRV and saliva testosterone-to-cortisol (T:C) ratio concentrations (β = -0.218, 95% CI -0.391 to -0.044, p=< 0.05). Daily heart rate variability assessment showed a significant negative relationship with saliva T:C ratio (β = -0.218; 95% CI -0.391 to -0.044; p < 0.05) and 95% sensitivity for detecting changes.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: