Abstract
Abstract
Purpose
This study aimed to quantify sleeping heart rate (HR) and HR variability (HRV) alongside circulating tumor necrosis factor alpha (TNFα) concentrations during 12-week Basic Military Training (BMT). We hypothesised that, despite a high allostatic load, BMT would increase cardiorespiratory fitness and HRV, while lowering both sleeping HR and TNFα in young healthy recruits.
Methods
Sixty-three recruits (18–43 years) undertook ≥ 2 overnight cardiac frequency recordings in weeks 1, 8 and 12 of BMT with 4 h of beat-to-beat HR collected between 00:00 and 06:00 h on each night. Beat-to-beat data were used to derive HR and HRV metrics which were analysed as weekly averages (totalling 8 h). A fasted morning blood sample was collected in the equivalent weeks for the measurement of circulating TNFα concentrations and predicted VO2max was assessed in weeks 2 and 8.
Results
Predicted VO2max was significantly increased at week 8 (+ 3.3 ± 2.6 mL kg−1 min−1; p < 0.001). Sleeping HR (wk1, 63 ± 7 b min−1) was progressively reduced throughout BMT (wk8, 58 ± 6; wk12, 55 ± 6 b min−1; p < 0.01). Sleeping HRV reflected by the root mean square of successive differences (RMSSD; wk1, 86 ± 50 ms) was progressively increased (wk8, 98 ± 50; wk12, 106 ± 52 ms; p < 0.01). Fasted circulating TNFα (wk1, 9.1 ± 2.8 pg/mL) remained unchanged at wk8 (8.9 ± 2.5 pg/mL; p = 0.79) but were significantly reduced at wk12 (8.0 ± 2.4 pg/mL; p < 0.01).
Conclusion
Increased predicted VO2max, HRV and reduced HR during overnight sleep are reflective of typical cardiorespiratory endurance training responses. These results indicate that recruits are achieving cardiovascular health benefits despite the high allostatic load associated with the 12-week BMT.
Funder
Defence Science and Technology Group
The University of Wollongong
Publisher
Springer Science and Business Media LLC
Subject
Physiology (medical),Public Health, Environmental and Occupational Health,Orthopedics and Sports Medicine,General Medicine,Public Health, Environmental and Occupational Health,Physiology
Cited by
3 articles.
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