Dataset Information

Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers.

ABSTRACT: Introduction:Diving close to the Arctic circle means diving in cold water regardless of the time of year. The human body reacts to cold through autonomous nervous system (ANS)-mediated thermoregulatory mechanisms. Diving also induces ANS responses as a result of the diving reflex. Materials and Methods:In order to study ANS responses during diving in Arctic water temperatures, we retrospectively analyzed repeated 5-min heart rate variability (HRV) measures and the mean body temperature from dives at regular intervals using naval diving equipment measurement tests in 0°C water. Three divers performed seven dives without physical activity (81-91 min), and two divers performed four dives with physical activity after 10 min of diving (0-10 min HRV recordings were included in the study). Results:Our study showed a significant increase in parasympathetic activity (PNS) at the beginning of the dives, after which PNS activity decreased significantly (measure 5-10 min). Subsequent measurements (15-20 min and onward) showed a significant increase in PNS activity over time. Conclusion:Our results suggest that the first PNS responses of the human diving reflex decrease quickly. Adverse effects of PNS activity should be considered on long and cold dives. To avoid concurrent sympathetic (SNS) and PNS activity at the beginning of dives, which in turn may increase the risk of arrhythmia in cold water, we suggest a short adaptation phase before physical activity. Moreover, we suggest it is prudent to give special attention to cardiovascular risk factors during pre-dive examinations for cold water divers.

SUBMITTER: Lundell RV

PROVIDER: S-EPMC7005786 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers.

Lundell Richard V RV Räisänen-Sokolowski Anne K AK Wuorimaa Tomi K TK Ojanen Tommi T Parkkola Kai I KI

Frontiers in physiology 20200131

<h4>Introduction</h4>Diving close to the Arctic circle means diving in cold water regardless of the time of year. The human body reacts to cold through autonomous nervous system (ANS)-mediated thermoregulatory mechanisms. Diving also induces ANS responses as a result of the diving reflex.<h4>Materials and methods</h4>In order to study ANS responses during diving in Arctic water temperatures, we retrospectively analyzed repeated 5-min heart rate variability (HRV) measures and the mean body temper ...[more]

PMID: 32082177

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Project description:IntroductionStrict lockdown rules were imposed to the French population from 17 March to 11 May 2020, which may result in limited possibilities of physical activity, modified psychological and health states. This report is focused on HRV parameters kinetics before, during and after this lockdown period.Methods95 participants were included in this study (27 women, 68 men, 37 ± 11 years, 176 ± 8 cm, 71 ± 12 kg), who underwent regular orthostatic tests (a 5-minute supine followed by a 5-minute standing recording of heart rate (HR)) on a regular basis before (BSL), during (CFN) and after (RCV) the lockdown. HR, power in low- and high-frequency bands (LF, HF, respectively) and root mean square of the successive differences (RMSSD) were computed for each orthostatic test, and for each position. Subjective well-being was assessed on a 0-10 visual analogic scale (VAS). The participants were split in two groups, those who reported an improved well-being (WB+, increase >2 in VAS score) and those who did not (WB-) during CFN.ResultsOut of the 95 participants, 19 were classified WB+ and 76 WB-. There was an increase in HR and a decrease in RMSSD when measured supine in CFN and RCV, compared to BSL in WB-, whilst opposite results were found in WB+ (i.e. decrease in HR and increase in RMSSD in CFN and RCV; increase in LF and HF in RCV). When pooling data of the three phases, there were significant correlations between VAS and HR, RMSSD, HF, respectively, in the supine position; the higher the VAS score (i.e., subjective well-being), the higher the RMSSD and HF and the lower the HR. In standing position, HRV parameters were not modified during CFN but RMSSD was correlated to VAS.ConclusionOur results suggest that the strict COVID-19 lockdown likely had opposite effects on French population as 20% of participants improved parasympathetic activation (RMSSD, HF) and rated positively this period, whilst 80% showed altered responses and deteriorated well-being. The changes in HRV parameters during and after the lockdown period were in line with subjective well-being responses. The observed recordings may reflect a large variety of responses (anxiety, anticipatory stress, change on physical activity…) beyond the scope of the present study. However, these results confirmed the usefulness of HRV as a non-invasive means for monitoring well-being and health in this population.

Project description:PurposeInterstitial cystitis/bladder pain syndrome and myofascial pelvic pain are frequently comorbid chronic pelvic pain disorders. Differences in bladder function between interstitial cystitis/bladder pain syndrome and myofascial pelvic pain suggest that efferent autonomic function may differentiate these syndromes. Heart rate variability, defined as the difference in duration of successive heartbeats, serves as an index of autonomic function by measuring its ability to modify heart rate in response to neurophysiological changes. High frequency heart rate variability was used as a reflection of more rapid vagally mediated (parasympathetic) changes. Low frequency heart rate variability signified slower fluctuations related to the baroreflex and sympathetic outflow.Materials and methodsHeart rate variability was derived by autoregressive frequency analysis of the continuous electrocardiogram recording of heart rate with the subject supine for 10 minutes, tilted 70 degrees with the head up for 30 minutes and supine again for 10 minutes. This institutional review board approved study included 105 female subjects, including 32 who were healthy, and 26 with interstitial cystitis/bladder pain syndrome, 12 with myofascial pelvic pain and 35 with interstitial cystitis/bladder pain syndrome plus myofascial pelvic pain.ResultsIn all positions healthy controls had higher high frequency heart rate variability than women with interstitial cystitis/bladder pain syndrome and interstitial cystitis/bladder pain syndrome plus myofascial pelvic pain. Subjects with myofascial pelvic pain were similar to controls with greater high frequency heart rate variability at baseline (supine 1) and in upright positions than subjects with interstitial cystitis/bladder pain syndrome. Differences in low frequency heart rate variability were less evident while low-to-high frequency ratio differences appeared to be driven by the high frequency heart rate variability component.ConclusionsSubjects with interstitial cystitis/bladder pain syndrome had diminished vagal activity and a shift toward sympathetic nervous system dominance. Overall these data support the hypothesis that changes in autonomic function occur in interstitial cystitis/bladder pain syndrome but not in myofascial pelvic pain. These changes may result from interstitial cystitis/bladder pain syndrome or contribute to its pathophysiology through abnormal self-regulatory function.

Dataset Information

Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers.

Publications

Diving in the Arctic: Cold Water Immersion's Effects on Heart Rate Variability in Navy Divers.

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