Abstract
The purpose of this study was to assess the differences in cardiac autonomic modulation
during maximal static (SA) and dynamic (DA) underwater apneas. Arterial oxygen saturation
(SpO2), heart rate (HR) and HR variability (SD1 from Poincaré plot and short-term fractal-like
scaling exponent, α1) were analyzed at the immersed baseline (3 min) and initial, mid- and end-phases (each 30 s) of SA and DA in nine elite breath-hold divers. DA and SA lasted 78±8 and 225±20 s (mean±SEM), respectively, and resulted in similar decrements in end-stage SpO2 (78±3 and 75±3%, p=0.352). During DA, initial increase in HR (from 80±5 to 122±5 bpm, p<0.001) was followed by gradual decrease towards the baseline at mid-apnea and end-apnea
phase (101±6 and 80±8 bpm, respectively). During SA, HR decreased at mid-apnea (from 78±4 to 66±3 bpm, p=0.004) but did not decrease further at end-apnea phase (66±4 bpm). Decreased SD1 was observed at the initial phase of DA (from 28±5 to 10±4 ms, p=0.005) being lower compared with SA (24±4 ms, p=0.005). At the end of DA and SA, SD1 tended to increase above the baseline (62±16 and 66±10 ms, p=0.128 and p=0.093, respectively, p=0.602 DA vs. SA). α1 tended to be higher at the end of DA compared with SA (1.17±0.10 vs. 0.79±0.10, p=0.059). We concluded that apnea blunts the effects of exercise on cardiac vagal activity
at the end of DA. However, higher HR during DA compared with SA indicates larger cardiac
sympathetic activity during DA, as suggested also by slightly higher α1.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Autonomic Neuroscience: Basic and ClinicalAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- The “diving bradycardia” in exercising man.Acta Physiol. Scand. 1968; 73: 527-535
- “Diving reflex” in man: its relation to isometric and dynamic exercise.J. Appl. Physiol. 1972; 33: 27-31
- Cardiovascular changes during underwater static and dynamic breath-hold dives in trained divers.J. Appl. Physiol. 2011; 111: 673-678
- The human respiratory gate.J. Physiol. 2003; 548: 339-352
- Angiography of the inferior vena cava of the harbor seal during simulated diving.Am. J. Physiol. 1971; 220: 1155-1157
- Sinus arrhythmia in man: influence of tidal volume and oesophageal pressure.Scand. J. Clin. Lab. Invest. 1975; 35: 487-496
- Early and late effects of exercise and athletic training on neural mechanisms controlling heart rate.Cardiovasc. Res. 1993; 27: 482-488
- Relationship of heart rate variability to parasympathetic effect.Circulation. 2001; 103: 1977-1983
- Seventy years of the Bainbridge reflex.Acta Physiol. Scand. 1987; 130: 177-185
- Cardiovascular regulation during apnea in elite divers.Hypertension. 2009; 53: 719-724
- Ultra-short-term heart rate variability for early risk stratification following acute ST-elevation myocardial infarction.Cardiology. 2009; 114: 275-283
- Saturation of high-frequency oscillations of R–R intervals in healthy subjects and patients after acute myocardial infarction during ambulatory conditions.Am. J. Physiol. Heart Circ. Physiol. 2004; 287: H1921-H1927
- Embedded data logging platform for research in diving physiology.in: Proceedings of the 7th International Workshop on Intelligent Solutions in Embedded Systems. 7. 2009: 43-48
- Static apnea effect on heart rate and its variability in elite breath-hold divers.Aviat. Space Environ. Med. 2008; 79: 99-104
- Hypoxia augments apnea-induced peripheral vasoconstriction in humans.J. Appl. Physiol. 2001; 90: 1516-1522
- Sympathetic–parasympathetic interactions in the heart.Circ. Res. 1971; 29: 437-445
- Differing sympathetic and vagal effects on atrial fibrillation in dogs: role of refractoriness heterogeneity.Am. J. Physiol. 1997; 273: H805-H816
- Cardiovascular responses to active and passive cycling movements.Med. Sci. Sports Exerc. 1994; 26: 709-714
- Restoration of hemodynamics in apnea struggle phase in association with involuntary breathing movements.Respir. Physiol. Neurobiol. 2008; 161: 174-181
- Effect of metabolic products of muscular contraction on discharge of group III and IV afferents.J. Appl. Physiol. 1988; 64: 2306-2313
- Reflex control of the circulation during exercise: chemoreflexes and mechanoreflexes.J. Appl. Physiol. 1990; 69: 407-418
- Respiratory sinus arrhythmia in dogs. Effects of phasic afferents and chemostimulation.J. Clin. Invest. 1991; 87: 1621-1627
- An underwater blood pressure measuring device.Diving and Hyperb. Med. 2008; 38: 128-134
- Modification of the ‘dividing bradycardia’ by hypoxia or exercise.Respir. Physiol. 1984; 56: 245-251
- Diving bradycardia during rest and exercise and its relation to physical fitness.J. Appl. Physiol. 1970; 28: 614-621
- Heart rate variability. Standards of measurement, physiological interpretation, and clinical use.Eur. Heart J. 1996; 17: 354-381
- Quantitative beat-to-beat analysis of heart rate dynamics during exercise.Am. J. Physiol. 1996; 271: H244-H252
- Physiological background of the loss of fractal heart rate dynamics.Circulation. 2005; 112: 314-319
- Sympatho-vagal interaction in the recovery phase of exercise.Clin. Physiol. Funct. Imaging. 2011; 31: 272-281
Article info
Publication history
Published online: June 11, 2012
Accepted:
May 17,
2012
Received in revised form:
March 28,
2012
Received:
December 21,
2011
Identification
Copyright
© 2012 Elsevier B.V. Published by Elsevier Inc. All rights reserved.