Volume 4 Supplement 1

15th International Conference on Environmental Ergonomics (ICEE XV)

Open Access

Rapid habituation of the cold shock response

  • Clare M Eglin1Email author,
  • George Butt1,
  • Stephen Howden1,
  • Thomas Nash1 and
  • Joseph Costello1
Extreme Physiology & Medicine20154(Suppl 1):A38

https://doi.org/10.1186/2046-7648-4-S1-A38

Published: 14 September 2015

Introduction

Sudden immersion into cold water initiates a series of cardio-respiratory responses collectively known as the cold shock response (CSR) which may increase an individual's risk of drowning. The CSR is stimulated by a rapid fall in skin temperature and includes tachycardia, a reflex inspiratory gasp followed by uncontrollable hyperventilation. Repeated cold water immersions conducted over several days have been shown to reduce the magnitude of the CSR [1]. This study investigated whether an habituation could be achieved in a couple of hours; it was hypothesised that following this rapid habituation the CSR would be reduced on a subsequent cold water immersion.

Methods

Nine healthy males (mean [SD] age 21[2] years, height 179[7] cm, mass 76[13] kg) with no previous cold water exposure, undertook two head-out immersions into stirred water at 15 °C for 5 minutes wearing swimming trunks. These immersions were undertaken one week apart at the same time of day (IMM1 and IMM7). One or two days after IMM1, participants undertook five, 3-minute, head-out immersions into 15 °C water over a period of 55 to 120 min. In between each habituation immersion they rewarmed in a bath at 38 °C for 3 minutes and the next immersion occurred approximately 10 minutes later. Heart rate (fC), respiratory frequency (fR), tidal volume (VT) and inspiratory minute volume (VI) were measured prior to and during each immersion. Data for IMM1 and IMM7 were averaged over the following time periods: 0-30, 30-60, and 60-300 s and are presented as mean[sd].

Results

fC was reduced throughout IMM7 compared to IMM1 (0-30 s: 117[21] v 106[14] bpm; 30-60 s: 110[21] v 86[19] bpm; 60-300 s: 90[18] v 78[17] bpm; all P < 0.05). VI was attenuated in IMM7 compared to IMM1 over the first minute of immersion (0-30 s: 61.3[7.5] v 52.5[12.1] L.min-1; 30-60s: 50.8[13.5] v 40.5[13.6] L.min-1; P < 0.05) whereas fR was only reduced in the first 30 s from 37(11) to 29(9) breaths.min-1 (P < 0.05). The inspiratory gasp observed within the first 10 s of immersion was similar in IMM1 and IMM7 (2.44[0.62] v 2.71[0.64] L, p > 0.05) as was VT throughout the immersions.

Discussion

Repeated immersions conducted over a short time period (1-2 hours) on the same day resulted in a decrease in fC, fR and VI during the first 30 s of immersion. This may reduce the risk of drowning by attenuating ventilation and thus the risk of water aspiration as well as lowering fC and therefore cardiac strain on immersion. No reduction in either VT or the inspiratory gasp was observed, probably because fR decreased giving a longer duration for each inspiration. As previous studies [2] have indicated that fR is a better indicator of respiratory drive than VT during the CSR, the current findings suggest that respiratory drive was reduced following the rapid habituation protocol.

Conclusion

Rapid habituation to the CSR is possible and may provide a practical and inexpensive method of protection against drowning for individuals who are deployed at short notice to situations where they are at risk of accidental cold water immersion.

Authors’ Affiliations

(1)
Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth

References

  1. Tipton , et al: Temperature dependence of habituation of the initial responses to cold water immersion. Eur J Appl Physiol. 1998, 78: 253-57. 10.1007/s004210050416.View ArticleGoogle Scholar
  2. Tipton , et al: Human initial responses to immersion in cold water at three temperatures and after hyperventilation. J Appl Physiol. 1991, 70: 317-322.PubMedGoogle Scholar

Copyright

© Eglin et al.; 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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