Is heart rate variability actually a reliable index of training? Evidence from the COVID-19 pandemic lockdown.

PURPOSE: The COVID-19 crisis also affected elite sport severely, as elite athletes either stopped or drastically reduced their training regimen due to the lack of competitions and the mandatory lockdown. The aim of this study was to test whether heart rate variability was a reliable index of training load, which was dramatically altered due to the mandatory lockdown that occurred as a consequence of the COVID-19. METHODS: Training (volume and intensity) and heart rate variability of sixteen professional male (n = 8; body mass index = 22.2 ± 2.0) and female cyclists (n = 8; body mass index = 20.3 ± 1.1) before (4 weeks), during (7 weeks), and after (4 weeks) the mandatory lockdown were monitored. RESULTS: Individual analyses showed that the mandatory lockdown caused reliable reductions in training volume in 13 subjects (-96 to -7 % reductions in minutes), that were followed by an increase after the lockdown in all subjects (5 to 270%). In contrast, changes in training intensity were not homogenous across individuals. Crucially, changes in heart rate variability neither follow training load nor intensity at the individual level. CONCLUSIONS: Heart rate variability did not seem to be a reliable proxy of training load and/or intensity as many previous reports have suggested, even if training conditions changed dramatically overnight.

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No evidence of association between HRV and training load in a pool of professional athletes before, during, and after the first COVID-19 lockdown.

10.31236/osf.io/crm6q ◽

2021 ◽

Author(s):

Alejandro Javaloyes ◽

Daniele Marinazzo ◽

Daniel Sanabria ◽

Manuel Moya-Ramón ◽

José Ramón Lillo-Bevia ◽

...

Keyword(s):

Body Mass Index ◽

Heart Rate ◽

Heart Rate Variability ◽

Body Mass ◽

Mixed Model ◽

Elite Athletes ◽

Training Load ◽

Training Volume ◽

Specific Effects ◽

And Training

PURPOSE: The COVID-19 crisis also affected elite sport severely, as elite athletes either stopped or drastically reduced their training regimen due to the lack of competitions and the mandatory lockdown. The aim of this study was to test whether heart rate variability was a reliable index of training load, which was dramatically altered due to the mandatory lockdown that occurred as a consequence of the COVID-19. METHODS: Training (volume and intensity) and heart rate variability of sixteen professional male (n = 8; body mass index = 22.2 ± 2.0) and female cyclists (n = 8; body mass index = 20.3 ± 1.1) before (4 weeks), during (7 weeks), and after (4 weeks) the mandatory lockdown in Spain were monitored. RESULTS: Individual analyses showed that the mandatory lockdown caused reliable reductions in training volume in 13 subjects (-96 to -7 % reductions in minutes), that were followed by an increase after the lockdown in all subjects (5 to 270%). In contrast, changes in training load were not homogenous across individuals. Moreover, such changes were not matched by comparable variations in heart rate variability. A mixed model of the heart rate variability as a function of training volume and intensity revealed no significant modulation by these two variables, and subject specific effects on the slope. CONCLUSIONS: In this study, we did not find evidence of association between heart rate variability and training load and/or intensity as many previous reports have suggested, even if training conditions changed dramatically overnight.

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Effects of Metformin Added to Insulin in Adolescents with Type 1 Diabetes: An Exploratory Crossover Randomized Trial

Journal of Diabetes Research ◽

10.1155/2020/7419345 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Daizhi Yang ◽

Jinhua Yan ◽

Hongrong Deng ◽

Xubin Yang ◽

Sihui Luo ◽

...

Keyword(s):

Body Mass Index ◽

Heart Rate ◽

Heart Rate Variability ◽

Type 1 Diabetes ◽

Insulin Sensitivity ◽

Body Mass ◽

Autonomic Function ◽

Insulin Dose ◽

Glucose Variability

Background. To comprehensively assess the effects of metformin added to insulin on metabolic control, insulin sensitivity, and cardiovascular autonomic function in adolescents with type 1 diabetes. Materials and Methods. This was an exploratory, crossover, randomized trial conducted in adolescents with type 1 diabetes aged 12-18 years old. Participants were randomly received metformin (≤1000 mg/d) added to insulin for 24 weeks followed by insulin monotherapy for a subsequent 24 weeks or vice versa. Blood pressure, body mass index, insulin dose, estimated insulin sensitivity, glycated hemoglobin A1c (HbA1c), and lipid profiles were measured, with a 72-hour continuous glucose monitoring and 24-hour Holter monitoring performed at baseline, 24, and 50 weeks for the assessments of glucose variability and heart rate variability. Results. Seventeen patients with mean ± SD age 14.4 ± 2.3 years , body mass index 18.17 ± 1.81 kg / m 2 , median (IQR) diabetes duration 4.50 (3.58, 6.92) years, and HbA1c 9.0% (8.5%, 9.4%) were enrolled. The between-group difference in HbA1c of 0.28% (95% CI -0.39 to 0.95%) was not significant ( P = 0.40 ). Changes in body mass index, insulin dose, blood pressure, lipid profiles, and estimated insulin sensitivity were similar for metformin add-on vs. insulin monotherapy. Glucose variability also did not differ. Compared with insulin monotherapy, metformin add-on significantly increased multiple heart rate variability parameters. Conclusions. Metformin added to insulin did not improve metabolic control or glucose variability in lean/normal-weight adolescents with type 1 diabetes. However, metformin added to insulin significantly increased heart rate variability, suggesting that metformin might improve cardiovascular autonomic function in this population.

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Physical activity, body mass index and heart rate variability-based stress and recovery in 16 275 Finnish employees: a cross-sectional study

BMC Public Health ◽

10.1186/s12889-016-3391-4 ◽

2016 ◽

Vol 16 (1) ◽

Cited By ~ 12

Author(s):

Tiina Föhr ◽

Julia Pietilä ◽

Elina Helander ◽

Tero Myllymäki ◽

Harri Lindholm ◽

...

Keyword(s):

Physical Activity ◽

Body Mass Index ◽

Heart Rate ◽

Heart Rate Variability ◽

Body Mass ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional

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Body mass index is related to autonomic nervous system activity as measured by heart rate variability

European Journal of Clinical Nutrition ◽

10.1038/ejcn.2009.35 ◽

2009 ◽

Vol 63 (10) ◽

pp. 1263-1265 ◽

Cited By ~ 67

Author(s):

A Molfino ◽

A Fiorentini ◽

L Tubani ◽

M Martuscelli ◽

F Rossi Fanelli ◽

...

Keyword(s):

Body Mass Index ◽

Heart Rate ◽

Heart Rate Variability ◽

Nervous System ◽

Autonomic Nervous System ◽

Body Mass ◽

Autonomic Nervous System Activity ◽

System Activity ◽

Autonomic Nervous ◽

Nervous System Activity

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Heart rate variability estimates ventilatory threshold regardless body mass index in young people

Science & Sports ◽

10.1016/j.scispo.2017.06.005 ◽

2018 ◽

Vol 33 (1) ◽

pp. 39-46 ◽

Cited By ~ 1

Author(s):

M.G. Queiroz ◽

G. Arsa ◽

D.A. Rezende ◽

L.C.J.L. Sousa ◽

F.R. Oliveira ◽

...

Keyword(s):

Body Mass Index ◽

Heart Rate ◽

Heart Rate Variability ◽

Young People ◽

Body Mass ◽

Ventilatory Threshold

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Training-Load-Guided vs Standardized Endurance Training in Recreational Runners

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2016-0093 ◽

2017 ◽

Vol 12 (3) ◽

pp. 295-303 ◽

Cited By ~ 5

Author(s):

Moritz Schumann ◽

Javier Botella ◽

Laura Karavirta ◽

Keijo Häkkinen

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Oxygen Consumption ◽

Endurance Training ◽

Maximal Oxygen Consumption ◽

Endurance Performance ◽

Training Load ◽

Training Volume ◽

Treadmill Test ◽

Recreational Runners

Purpose:To compare the effects of a standardized endurance-training program with individualized endurance training modified based on the cumulative training load provided by the Polar training-load feature.Methods:After 12 wk of similar training, 24 recreationally endurance-trained men were matched to a training-load-guided (TL, n = 10) or standardized (ST, n = 14) group and continued training for 12 wk. In TL, training sessions were individually chosen daily based on an estimated cumulative training load, whereas in ST the training was standardized with 4–6 sessions/wk. Endurance performance (shortest 1000-m running time during an incremental field test of 6 × 1000 m) and heart-rate variability (HRV) were measured every 4 wk, and maximal oxygen consumption (VO2max) was measured during an incremental treadmill test every 12 wk.Results:During weeks 1–12, similar changes in VO2max and 1000-m time were observed in TL (+7% ± 4%, P = .004 and –6% ± 4%, P = .069) and ST (+5% ± 7%, P = .019 and –8% ± 5%, P < .001). During wk 13–24, VO2max statistically increased in ST only (3% ± 4%, P = .034). The 1000-m time decreased in TL during wk 13–24 (–9% ± 5%, P = .011), but in ST only during wk 13–20 (–3% ± 2%, P = .003). The overall changes in VO2max and 1000-m time during wk 0–24 were similar in TL (+7% ± 4%, P = .001 and –9% ± 5%, P = .011) and ST (+10% ± 7%, P < .001 and –13% ± 5%, P < .001). No between-groups differences in total training volume and frequency were observed. HRV remained statistically unaltered in both groups.Conclusions:The main finding was that training performed according to the cumulative training load led to improvements in endurance performance similar to those with standardized endurance training in recreational endurance runners.

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