Blood Pressure Response to Cold Water Immersion Test

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IJBPAS, November, 2012, 1(10): 1483-1491ISSN: 22774998

1483IJBPAS, November, 2012, 1(10)

BLOOD PRESSURE RESPONSE TO COLD WATER IMMERSION TEST

MISHRA S*, MANJAREEKA M AND MISHRA J

Department of Physiology, Kalinga Institute of Medical Sciences, KIIT Campus-5, Patia,

Bhubaneswar, Khurda District, Odisha -751024

*Corresponding Author: E Mail- [email protected] : Mob.: +919583236596

ABSTRACTThe aim of this study was to evaluate baseline and cold stress test values and to determine the

changes in blood pressure and heart rate. Thus providing a comprehensive overview of the

human physiological responses to acute cold exposure . Measurements of blood pressure by

Sphygmomanometer was made in 20 healthy young adults before the test and at 1min, 3min and

5min after immersing the hand up to wrist in cold water maintained at 5C. The initial 60secs of

the test represented vascular reactivity to the cold stimulus, and the hemodynamics at 5mins of

hand immersion represented the degree of circulatory adaptation to this stimulus. The statistical

analysis was done by paired t-test. Most patients responded to the cold pressor test with

statistically significant increase in diastolic blood pressure than systolic blood pressure. There

was 12.10% rise in systolic blood pressure and 16.02% rise in diastolic blood pressure with

23.09 % rise in heart rate. Heart rate increased significantly (p < 0.05) after 1min of immersion,

and by the end of 5mins it reached pre normal values (p < 0.05). The response to cold immersion

can be used to assess vascular disorders and predict hypertension in later life.

Keywords: Cold Pressor Test, Heart Rate, Sympathetic Activity, Hypertension,

Autonomic Function TestINTRODUCTION

Hines and Brown described an ice water

immersion test (cold pressor test, CPT or cold

immersion test) in 1932, to determine

individual vascular reactivity [1, 2] . They

observed that there were marked changes in

blood pressure when a person immersed an


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Mishra S et al Research Article


extremity in ice water. These studies showed

that there was sustained increase in blood

pressure (measured by indirect methods),

systolic rise of up to 20mmHg and diastolic

rise of up to 15mm Hg and this is considered

as normal response to the test [1] . Hines

applied this test nearly 5000 times in 1856

persons, in both normotensives (1015

persons) and hypertensives (841 persons) and

noted an average variation in response of 10

percent on repeated testing [2] . The cold

pressor response is considered a neurogenicreflex and indicates the pivotal role of

autonomic nervous system in regulation of

cardiovascular functioning in normal

individuals and also in several cardiac

diseases. Many studies have shown abnormal

response to cold pressor test in patients with

hypertension and used it as a predictor of

future cardiovascular dysfunction [3] .

The responses to cold immersion test in

normotensive subjects are increase in blood

pressure, heart rate, total vascular resistance,

muscle sympathetic nerve activity [4, 5, 6] ,

galvanic skin resistance and decrease in

forearm blood flow [7] . These changes are

mediated by sudden increase in peripheral

resistance due to vasoconstriction, the

underlying mechanism being autonomic

neural pathways [8] . The cold immersion test

is non-invasive and can be used as bedside

assessment of autonomic function in patients

with cardiovascular disease and evaluation of

vascular reactivity in healthy subjects.

The originally proposed cold immersion test

of Hines and Brown required immersing hand

up to the wrist in ice cold water at 5 degree

Centigrade for 5 minutes. Many studies have

been done using the above basic principle, but

making slight changes in the procedure. No

significant variation is seen by changing the

area exposed to cold water like immersing the

hand up to wrist, up to themetacarpophalangeal area, feet, fingers, face,

etc. Some studies showed that immersion up

to the metacarpophalangeal was better than

the method immersed up to the wrist as the

former had less pain but the results were

similar in both the study [9] . Same responses

were seen after changing the temperature of

cold water and the duration of exposure [10] .

Studies done in cold climates (winter) and

cold areas fell in alignment with the normal

results except for the fact that there was better

cold adaptation in the colder areas and during

winter than relatively warm areas [11] .

The research undertaken follows the basic

methodology of the standard Hines and

Browns cold immersion test in healthy,

normotensive individuals and aims at tracing

the effect of cold immersion test and


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determining if the autonomic response is

generalized or localized.

MATERIALS AND METHODS

This study was taken up in the Department of

Physiology, Kalinga Institute of Medical

Sciences, Bhubaneswar, Odisha from August

2011 to November 2011. The study was

conducted during this period when the

weather conditions were neither too hot nor

too cold; as the test results could be affected

due to cold adaptation in winter climate, and

in hot climate there would be increasedsensitivity to cold water. Subjects included in

the study were students from MBBS

curriculum of the same institute. After the

ethical permission, written informed consent

was taken from each subject on being

explained the purpose and procedure of the

test. 20 medical students (10 males and 10

females) with mean age group of 18.450.67

years, mean height of 161.17.7cms and

mean weight of 59.310.86 kg were taken for

this cross sectional study. Young age group

was preferred to avoid any vascular diseases

or hypertension.

Subjects having history of neurological

dysfunction, any systemic disease, sweating

disorder, hypertension, cold intolerance and

history of smoking or alcohol consumption

were excluded from the study. The subjects

were asked not to take any tranquilizers or

other drugs which could affect the

cardiovascular functioning of the subject at

least a week before the study. Any person

having a history or physical findings

suggestive of cardiovascular or renal disease

were excluded from the study. The subjects

were asked to come in the morning hours

after taking light breakfast and refrain from

caffeine intake 12 hours prior to the test.

Subjects were made to relax physically and

mentally for at least 15 minutes before the

initiation of the procedure. Indirect method of blood pressure recording

was preferred. Elkos Sphygmomanometer

was connected to both the arms and blood

pressure was recorded simultaneously. Heart

rate was calculated from 12- lead Holter

electrocardiogram. Heart rate and blood

pressure were recorded just before start of the

experiment. Blood pressure was recorded

three times before documenting the baseline

reading. The respiratory rate of the subject

was monitored throughout the experiment to

maintain at normal levels. The conventional

method of cold immersion test was followed

in which the left hand up to the wrist was

immersed in cold water of 5 degree centigrade

for 1 minute. An ice bucket with a

thermometer monitored the temperature of the

water at 5 degrees for maintaining uniformity.

Blood pressure and heart rate were recorded


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after removing the hand from cold water at

the end of 1 minute, and then at end of

3minutes and 5minutes. Blood pressure was

monitored in both the left (immersed) arm and

the right (non-immersed) arm to see if the

effect was localized or generalized. The

Systolic Blood Pressure (SBP), Diastolic

Blood Pressure (DBP) and Heart Rate (HR)

were compared and statistical analysis was

done by using Graph Pad Prism 5 software. p

value 0.05).

The response to cold immersion is

generalized as seen from Table 3, 4 and

Figure 3 .

The increase in blood pressure was recorded

in both the arms i.e. in the immersed left hand

and also in the non-immersed right hand when

compared at 1 minute and 5 minutes.

Table 1: Comparison of Various Parameters Before Cold Pressor Test (CPT) and at 1 Minute of Cold

Immersion

Mean SD

before CPT

Mean SD

at 1min

p value Percentage

rise (%)

SBP 119.1511.51 135.5611.32 0.0001* 12.10

DBP 79.959.38 92.7611.29 0.0004* 16.02

HR 82.9512.06 102.1112.83 0.0001* 23.09

* Statistically Significant


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Figure 1: Comparison of Various Parameters Before Cold Pressor Test (CPT) and at 1 Minute of Cold

Immersion

Table 2: Comparison of Various Parameters at 1 Minute and at 5 Minutes of Cold Pressor Test (CPT)

Mean SD at 1min Mean SD at 5min p value

Systolic BP 135.5611.32 122.7911.98 0.0013*

Diastolic BP 92.7611.29 81.5410.93 0.0028*

Heart Rate 102.1112.83 88.7311.02 0.0011*

*Statistically Significant

Table 3: Comparison of Blood Pressure of Immersed Arm (left arm) With Non-Immersed Arm (Right

Arm) at 1 Minute of Cold Immersion

1min Mean SD in left

arm

Mean SD in right

arm

p-value

Systolic BP 135.5611.32 133.4411.76 0.5648**

Diastolic BP 92.7611.29 90.5911.48 0.5412**

** Not Statistically Significant

Table 4: Comparison of Blood Pressure of Immersed Arm (Left Arm) With Non-Immersed Arm (Right Arm)

at 5 Minutes of Cold Immersion5min Mean SD in

left arm

Mean SD in right

arm

p-value

Systolic BP 122.7911.98 121.0111.45 0.6337**

Diastolic BP 81.5410.93 80.1411.11 0.6901**

**Not Statistically Significant

SBP DBP

119.15

79.95

135.56

92.76

122.79

81.54

B L O O D P R E S

S U R E

BP CHANGES IN CPT

before 1min 5min


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Figure 2: Heart Rate Changes In CPT

Figure 3: Changes in SBP and DBP

DISCUSSION

In the present study, the cardiovascular

response pattern of cold immersion test wascomprehensively assessed. Significant rise of

blood pressure and heart rates were seen in

healthy subjects, which is within the normal

limits as cited by Hines and Brown. The rise

in blood pressure above 20/20mm Hg is

considered as hyper-reactivity [12] , seen

mostly in hypertensive patients or subjects prone for hypertension in later life as

supported by some research works.

Stimulation of peripheral cold receptors have

Before 1min 5min

82.95

102.11

88.73

H E A R T R A T E

HEART RATE CHANGES IN CPT

SBP 1min SBP 5min DBP 1min DBP 5min

135.56122.79

92.7681.54

133.44121.01

90.5980.14 Left

Right


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been shown to strongly activate the

sympathetic nervous system [6, 13] .

Thus by knowing the autonomic function

status of an individual we can assess the

extent to which the cardiovascular function is

compromised, as the signs and symptoms of

autonomic dysfunction are late in progression.

Cardiovascular autonomic neuropathy possess

a higher risk of sudden cardiac death. Early

detection and correction of autonomic

imbalance restores longevity and preserves

the quality of life.Cold adaptation occurs generally involving a

gradual diminution in the Pressure response,

and the circulatory mechanisms responsible

for it, to continued (cold) stimulation [12] .

Some studies point towards a weak but

statistically significantly correlation between

the rating of perceived pain and the increase

in blood pressure during 1-min immersion of

hand in cold water. Pain induced by several

methods can stimulate muscle sympathetic

nerve activity, as in the case of cold pressor

test it may be stimulated by painful sensation

due to ice water. The hypothesis that pain or

noxious stimuli plays a role in resetting

baroreflex during the cold pressor test needs

further investigation [14] .

Our second goal was to determine if the

response to cold immersion test was a

generalised or localised response by

comparing the blood pressure changes in both

arms. As there was no significant increase in

blood pressure in the non-immersed hand,it

reflects that the response is not localized

rather a generalized one. Tests to determine

the type of response seen in cold immersion

test have been scantily documented. However

increased sympathetic reactivity to peripheral

cold receptors can be considered as the

probable mechanism for such a response seen

here.

Some studies have recorded a constantincrease in heart rate throughout the

procedure [11, 15] , but studies conducted by

some [6, 14, 16] showed marked increase in

heart rate follwed by slow decrease.

CONCLUSION

The pathway of regulation of cold pressor test

response cannot be determined by this test

and needs advanced research.There is a

controversial hypothesis that increased

cardiac output is mainly due to constantly

raised heart rate. This calls for further studies.

REFERENCES

[1] Hines EA Jr and Brown GE, The cold

pressor test for measuring the

reactibility of the blood pressure: data

concerning 571 normal and hypertensive

subjects, Am. Heart J., 11, 1936, 1-9.

[2] Wood DL, Sheps SG, Elveback LR,

Schirger A, Cold pressor test as a


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M, Repeatability of heart rate

variability during simple cardiovascular

reflex tests on healthy subjects,

Archives of Medical Research, 32,

2001, 21-26.

[16] Sendowski I, Savourey G, Launay JC,

Besnard Y, Cottet-Emard JM,

Pequignot JM and Bittel J, Sympathetic

stimulation induced by hand cooling

alters cold-induced vasodilatation in

humans, Eur. J. Appl. Physiol., 81,

2000, 303-309.

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Blood Pressure Response to Cold Water Immersion Test