THE

ICE W

ATER

CHALL

ENGE &

THE

BRAIN

AN

DR

EW

JO

NE

S

INTRODUCTION

In recent months a new craze has travelled the world involving dumping a large volume of iced water over an individual’s head

The purpose of this presentation is to show the connection between the brain and the response people have to sudden temperature changes.

THERMOREGULATION

Thermoregulation managed by hypothalamus as part of homeostasis

The hypothalamus stimulates vasoconstriction or vasodilation in response to temperature changes

CHANGES IN TEMPERATURE

When a change in temperature is detected, the hypothalamus prompts either vasodilation or vasoconstriction.

Vasodilation occurs when there is an increase in temperature to send blood the skin to cool off before returning to the essential organs (i.e. brain, heart, lungs) to prevent over heating.

Vasoconstriction occurs when a decrease in temperature is detected to prevent a cooling off and keeping the warm blood around the essential organs.

SUDDEN CHANGES IN TEMPERATURE

The body does not like sudden changes in temperature.

Typically, this can be seen when people faint on entering very hot rooms. The body attempts to adapt to the new temperature quickly and vasodilates quickly. The rapid vasodilation causes a sudden drop in blood pressure and the person faints.

In contrast, sudden chilling causes vasoconstriction. Pain can occur in the peripheries due to the sudden vasoconstriction and exposure to the cold temperatures.

ICE WATER CHALLENGE

The Ice Water Challenge originated as the Cold Water Challenge in America. Participants were challenged to dive into cold water or get doused in ice water and nominate their friends in support of their charity of choice.

Social media caused the craze to reach New Zealand and the Child Cancer Foundation has promoted it as form of fundraising activity

RESPONSE TO ICE CHALLENGE

After people’s breath is taken away from the shock they pant to try and regain their breath. At the same time the blood vessels vasoconstrict and the skin goes pale.

Once the challenge is finished, the participants begin to shiver and their skin goes red as the blood vessels vasodilate and draw warm blood back to the surface to reheat the surface.

If more than one person has done the challenge, they then huddle!

APPLICATION OF LEARNING

Having completed the Understanding the Brain MOOC, I have a greater understanding of homeostasis and in this case, thermoregulation.

Based on this knowledge I have been able to look at the Ice Water Challenge with a new perspective. The ice water challenge does not change the ‘set point’ of thermoregulation due to its short duration but does result in rapid vasoconstriction and vasodilation to protect the vital organs, including the brain.

Exposure to icy water for a far longer time (like being falling off a boat in the Southern Ocean) would result in a change in the set point and significant hypothermia.