Scott smith

SCOTT P J. SMITH. COLD WATER IMMERSION COPARISON WITH HEART RATE

The physiological responses in cold water immersion comparing the wetsuit and dry suit Scott P J. Smith Department of Falmouth marine school, 2nd year foundation marine sports science Mail address, 248 Longfield Falmouth Cornwall TR11 4ST Email scott.smith272@live.cornwall.ac.uk. Tel, 01326210488

This research was done at Falmouth Marine school in the top shed

Cold water immersion Comparison with heart rate

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ABSTRACT The purpose of this study is to see if there is a significant difference between the heart rate in cold water immersion when comparing a wetsuit and a dry suit, The 5 subjects were submerged into a cold water tank with wetsuits while there heart rate will be recorded for 10min, then again in the dry suit, However there was no significant difference between the heart rate’s results as it was greater than the 0.05 critical analysis, The discussion also found that there could have been more variables in the experiment to make the results more accurate and to have a different outcome than the (p>0.805) mean result.

INTRODUCTION There are many wetsuits and dry suits available out there on the market and one of the most important things on the water is to avoid hypothermia at all costs, unfortunately sometimes you may not have a choice, so this reports purpose is to see whether a wet-suit or a dry suit would be more beneficial to prevent the heart rate from dropping and an individual from going into hypothermia in cold water shock, This reports experiment will use 5 subjects and subject them to cold water immersion once in a wetsuit and once in a dry suit and record there heart rate and see if there is a significant difference on an average over the 5 subjects, this was done in 10min period each while there heart rate is recorded every 20 sec. The anticipated outcome of this report is to see if there is a significant difference between the physiological heart rate when immerged in cold water while wearing a dry suit compared to a wetsuit.

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To check the relevance of this report a literature review was undertaken, while doing this the following papers were found to further understand the problem within the report. In S. Vybiral et al (7) report there were 7 men that were cold water adapted and 6 that were not the report aim was to see if there was any significant differences between the thermoregulatory responses of the two groups and the significance of any changes in the body’s temperature and the mechanisms in the body that trigger the heat loss. Which we can relate to this reports hypothesis as it is looking to see if there is a significant difference between heart rate which will be affected by loss of heat through the wet suit or the dry suit. John W. Castellani (4) report also tested difference to body core temperature while immersed in cold water but with a difference of exercises included throughout thee submergence.

In P.Tikuisis et al (6) report they tested the thermoregulatory responses against woman in comparison to men in cold water immersion. P.Tikuisis et al (6) stated that there” hypothesis was, woman and men exhibit similar changes in body cooling and metabolism during cold exposure when subject responses are corrected for body fat, they also said that in woman a higher percentage of metabolism during cold water immersion would be due to fat than was previously observed for men”. This relates to this report as this report includes both male and female subjects that are going into cold water immersion. David W. DeGroot et al (2) was to test cold water stress with old and young subjects with a mix of male and female which in comparison with the reports testing’s it can relate to the female and the males that are young and the difference between them in cold water immersion.

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Michael J. Tipton (5) report was to test to see if cold water immersion was more central or peripheral which is a vital part of this reports experiment as certain parts of the body were not covered that were submerged. This was also talked about by François Haman (3) but he also tested the factors from shivering to stop the decrease in body temperature. Michael M. Toner (1) report was to see if having different parts of the body in the water would change the thermal and metabolic rate they tested them shoulder level which will be relate to this reports experiment.

METHOD SUBJECTS There are 5 asymptomatic colleagues. 20 +- 2 year’s female/male participated in this experiment, they are all sports enthusiast and are physically active the information on each subject can be shown in table 1. They were all given a consented form to sign before they participated for this Information.

Subject Letter A B C D E

Male/female

M M M M F Mean Table 1 of subjects

Age

20 20 19 22 21 20

Height (ft., inches) 6 5, 8 6, 2 6, 3 5, 3 5, 9

Weight (stone) 10 18 14 13,5 9 12.9

Resting heart Rate for drysuit 73 70 65 83 69 72

Resting heart rate for wetsuit 70 111 98 68 69 83

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EXPERIMENTAL PROCEDURES EXPLAINED The subjects were asked for any medical/physiological conditions that will affect any data collected. The subjects were asked to lie down in the supine position for one minute while there heart rate is monitored and recorded. The subjects were then measured for height by an industrial tape measure of 3 meters in length then they were weighed and they then filled out a form with their age. The subject was then asked to put the heart monitor on, and to make sure it was around the pectoncis major and was recording an accurate heart rate. The tank full of water which is 4ft width, 16length, 4height and half-filled and the amount of water in the tank is 3624.96liters, the subject was then asked to get into their dry suit and to climb into the tank full of water at 16 degrees as soon as they sat down and the water was just below the neck line, the stopwatch then started and every 20 sec there heart rate was recorded, up to 10min, at the end of the 10min, the subject was helped out if the tank and warmed up, when the heart rate returned to the normal resting heart rate of that subject, he/she was then asked to climb into a dry-wetsuit and to re-enter the tank were they sat down and submerged themselves up to the neck line again, were the heart rate was recorded every 20secs up to 10min, at the end of the 10min period they were helped back out of the tank and got themselves warmed up and back into their normal clothes while returning the heart rate monitor this was then repeated another 4 time’s with the other subjects. The wetsuit was 5,4,3mm thick and the dry suit was a Surface Sports front zip edition and was used on all subjects.

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STATISTICAL ANALYSIS The test chosen was the paired t-test as it was a comparison with continuous data that had two means and was the same set of data which was (dependent), the normality of the test is not an issue due to the fact there are over 20 comparison of mean data, there is no unusual data which can have a strong effect on the end results so it’s very accurate, this is the reason for using the paired t-test for this report , the test used an alpha of (P > 0.05) and was considered for the comparison of the two different pieces of data. The difference of the power is between 3.0928 and 4.5334 if this is the case then there is only a 60% chance that the means are differed by 3.0928 and a 90% chance that it is differed by 4.5334 for the power to be below 3.9168 at 80% chance this report would have to increase in the amount of samples used.

RESULTS Figures (3,4,5,6,7) shows the raw data of each individual in comparison with the wetsuit and the dry suit heart rate without it being averaged, figure (8,9) shows the raw date with the wetsuit and the dry suit that hasn’t been averaged or compared to each other at each 30sec interval, the heart rate was recorded at the end each individuals heart rate interval they were added up the divided by 5 which gave the mean, this was done for the full 10mins of the experiment for wetsuit and dry suit, the mean results for each of the two statistics where calculated by the paired t-test, the test statistical came to (p>0.805) which is greater than the 0.05 critical value, which means that null hypothesis was rejected as you can see from figure 1, as you can see from figure 2 there is not enough samples of data to conclude the power results,

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there would have to be a few more samples of date to see if there would be any significant change.

Figure 1 screen shot of Minitab results

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Figure 2 screen shot of Minitab results DISCUSSION There have been a number of studies in cold water immersion but not that many in testing the heart rate while wearing wetsuits and dry suits and comparing them, however the studies in body temperature can relate to many studies like (1,2,3,4,5,6,7). In study (7) they concluded that there was a significant difference in their results as the heart rate rapidly increased then decreased which is the opposite of this reports conclusion as you can see from figure 1 there is no significant difference, figure 2 showed the power to be insignificant due to the lack of samples to make a significant difference this was also the case for study (5). However this report experiment were undertaking straight after each other which could of influenced the final statistical results as from (1,2,4,5,6) were done over a period of 2-4 days in doing this there

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could have been more variables, but with this report those would be taking out of account but the initial response of getting in and out of the tank almost straight away can affect the way the heart rate response which is proved in (3,5), so straight away this reports experiment could of used more subjects and been done over two days to have a more accurate power reading through doing the paired t test, however the data was correct as there was no unusual data to skew the results as shown in figure 2, the standard deviation is 95% accurate that there is a difference of 3.1072 dry suit and 2.4405 wetsuit this can be seen under figure 1. This can be closely related to other studies like (1,2,4,5,6) which had a similar outcome for the standard deviation, this can be affected by the temperature of the water in this report it was 16 degrees in a tank with no wind chill factor, which in study (3) proved that the wind chilled factor was a big part in hypothermia. In study (7) the water was 10 degrees which did show a statistical difference in cold water immersion which could of changed the results, in study (6) it showed that the difference between men and woman was not that much when the body fat is taking into account but there is with metabolism in fact it is almost doubled in woman, if this is the case then this report experiment should of taking into the account of body fat to make the results more conclusive, study (2) showed that age difference in cold water immersion was not an important factor, as there statistical results showed no difference between the groups, as a result from this study, it can be verified that this reports experiment did not have to take age in consideration even though there was only a space of 4 years between the group. Study (1) should that when the body was submerged into cold water it had a significant difference in body temperature but the knee, and hips did not. So with this reports experiment one of the variables that did not matter were the fact that the subjects wore no shoes during the cold

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water immersion and it would not affect the (p-0.805) this was also supported by study (4).

Study (3) showed that shivering is the body’s response from cold water to keep the blood moving so the important organs can carry doing there job, this is another variable to this reports test, but as this reports test was only done for 10min there was no shivering to take place so this can be ruled out of this experiment, also in (3) study the report also mentioned that what they eat previously did have an effect on their metabolic rate which helped with the body’s heat lose, however this report subjects were not monitored for their intake on food or liquid so this is a variable that could of changed the statics analysis of this report. This report could have been more accurate but it would mean putting subject’s health at risk or even death which is against ethical protocol, this report could have looked at real life situations and compare them with the results, the problem that lies with this theory is not everyone in that situation takes there heart rate in till they are rescued.

PRACTICAL APPLICATIONS There are many different wetsuits and dry suits out there on the market and as far as the results go from this report, it is more down to personal choice and what you would be more comfortable in, but as this test was only undertaken in 16 degrees of water and for 10min, it might be advisable to look for future studies that may provide more accurate information for a longer period of time of cold water immersion with the differences between wetsuits and dry suits and which one may be more suitable for prevention of hypothermia.

REFERENCES

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(1)DAE T. LEE, MICHAEL M. TONER, WILLIAM D. MCARDLE, IOANNIS S. VRABAS, AND KENT B. PANDOLF Thermal and metabolic responses to cold-water immersion at knee, hip, and shoulder levels. J Appl Physiol 82:1523-1530, 1997 (2)David W. DeGroot, 1George Havenith, 2 and W. Larry Kenney Responses to mild cold stress are predicted by different individual characteristics in young and older subjects J Appl Physiol 101: 1607–1615, 2006 (3)Francois. Haman Shivering in the cold: from mechanisms of fuel selection to survival J Appl Physiol 100: 1702–1708, 2006 (4)John W. Castellani, Catherine O’Brien, Peter Tikuisis, 3Ingrid V. Sils, and Xiaojiang Xu2.

Evaluation of two cold thermoregulatory models for prediction of core temperature during exercise in cold water. J Appl Physiol 103: 2034–2041, 2007 (5)Michael J. Tipton, Clare M. Eglin and Frank St C. Golden Habituation of the initial responses to cold water immersion in humans: a central or peripheral mechanism Journal of Physiology (1998), 512.2, pp.621—628 (6)P. TIKUISIS, I. JACOBS, D. MOROZ, A. L. VALLERAND, AND L. MARTINEAU. Comparison of thermoregulatory responses between men and women immersed in cold water. J Appl Physiol 89:1403-1411, 2000 (7)S. Vybiral, I. Lesna, L. Jansky and V. Zeman Thermoregulation in winter swimmers and physiological significance of human catecholamine thermogenesis. Exp. Physiol 85.3: 321-326, 2012

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ACKNOWLEDGEMENTS Thanks to the marine school for letting me use the Tank and to all my subjects who participated in the experiment, also to the marine school library staff for their support and help, also to Channy who has supported me throughout this project and offered me help all the way through.