cold water immersion

Question 1

4 stages of cold water immersion

Answer 1

• initial immersion responses or “cold shock”
• short term immersion or swimming failure
• hypothermia (body core temperature of 35C or below)
• post rescue collapse or circus-rescue collapse

Question 2

physiological factors of stage 1

Answer 2

strong efferent signals from skin receptors to brain, large inspiratory gasp followed by big increase in ventilation, large increase in heart and BP, small muscle spasms tetany and drowning

Question 3

duration of stage 2 and recommendation for survival

Answer 3

first 2-3 minutes, float first and kick for your life (tred water)

Question 4

skilled versus less skilled swimmers in cold shock

Answer 4

universal feature that occurs regardless of skill, PETCO2 and swim duration influenced by water temperature, initial drop in brain blood flow but after increased by 30% above resting level despite increase in hyperventilation-induce hypercapnia, experience could cope with respiratory ctrl in cold water better

Question 5

training cold-water response

Answer 5

no effect on brain blood flow but decrease breathing response reduced and improved, suggested ice cold water inhaled in lungs rapidly cools heart and brain and acts as a protective mechanism to prevent drowning

Question 6

stage 2 short term immersion or swimming failure

Answer 6

rapid muscle and nerve cooling , about 5-30 minutes, swimming failure common , angle of attack increases, drag increases, stroke rate increases and stroke length decreases

Question 7

stage 3 hypothermia

Answer 7

sometime after 30 minutes, deep body temperature falls until unconscious, drowning through incapacitation or cardiac arrest

Question 8

rate of body core cooling depends on

Answer 8

water temperature and sea state, clothing, body fat, amount of body immersed in water, behaviour, shivering thermogenesis

Question 9

stage 4 post rescue collapse

Answer 9

basic cause of death due to a collapse of blood pressure, risk of ‘after drop’ via inappropriate reheating, better to lay horizontal as increase blood to brain and heart, an exercise enhancement of after drop could predicate post rescue collapse

Question 10

what water temperature provokes physiological reaction of cold shock

Answer 10

15C or below

Question 11

submersion of head/face in water -paradoxical response

Answer 11

stimulation of the trigeminal nerve reflecting response and prolonged breath hold + bradycardia (decreased HR- parasympathetic)

Question 12

autonomic conflict

Answer 12

occurs when both divisions of the autonomic nervous system are coactivated - sympathetic activation due to exercise/performance stimuli and parasympathetic activation due to to face/head immersion, water in nasopharynx and extended breath hold