Danger! – Fifth Sense
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GeorgeMost of us are probably aware that smell is the primary sense for many animals.  Take a dog, for example; its sense of smell is supposedly around a thousand times more powerful than our own, which is why we use them for tasks like finding drugs in airport luggage, or searching for survivors in the ruins created by an earthquake.  Dogs, moving around on all fours with their noses close to the ground, rely on their sense of smell to find food, warn them of danger, and therefore survive.

The human sense of smell, by contrast, has become of lesser importance since we evolved from walking on all fours; our noses moved away from the ground and our eyes moved to a higher vantage point, so gradually our eyesight became more important than our sense of smell.  Think about navigation, for example; we use visual stimuli such as maps and signs to find our way around, and have done so for many hundreds of years.  We don’t use smell to find our way around like dogs do.  Whilst the world in which we live presents many difficulties for someone deprived of their ability to see, not possessing a sense of smell doesn’t really cause much of a problem.

Or does it?  Our sense of smell, and taste, still provides us with a very important early-warning system when it comes to objects or situations that may cause us harm.  Food that has gone bad can sometimes look ok to the naked eye, but the smell it gives off tells us not to eat it.  There is a reason why we find the smells of decaying food, raw sewage, and ammonia repulsive – it is our bodies telling us to avoid these things as they will cause us damage.

The power of our olfactory system to warn us of possible danger may be greater than we think; the following story comes from a friend of ours, Lynn, who noticed a marked increase in her sensitivity to smells when she was in a vulnerable situation:

“There were two separate occasions when I really noticed a difference in the strength of my sense of smell to usual.  The first was in hospital, after I’d had an operation.  The smell of the perfume that different nurses were wearing was really overpowering, enough to make me feel ill!  At the time I remember thinking, ‘someone needs to talk to them about the amount of perfume they are putting on, this is a hospital after all’.  The second occasion was after I had broken one of my legs; I was back at home, with my leg in a cast, in pain and finding it very difficult to move around.  I was laid upstairs on the sofa, and my husband was downstairs cleaning the kitchen.  He must have been using some sort of cleaning spray, and all of a sudden I could smell it really strongly.  I couldn’t understand how the smell could be so powerful when it was so far away from me, down a flight of stairs, but in hindsight I actually think that my sense of smell must have been heightened by the fact that I was unable to move around – and therefore get away from any possible danger – because of my leg.  It was as if my body was providing me with additional warning of anything that could cause me any harm, and compensating for the fact that I couldn’t get away easily.”

The above demonstrates something we are aware of already; that the human brain is capable of compensating for a deficiency in one area by increased sensitivity in others.  People who lose their sight often say that their hearing or sense of smell, or both, becomes much more sensitive.  What does this mean for anosmia sufferers, however?  Does sudden smell loss result in an improvement in one or more of the other senses?

As far as we are aware, no study has ever been done to test this.  Anosmia sufferers do however, have to be much more aware of some of the dangers discussed above than those of us with fully-functioning olfactory systems, such as gone-off food – and what if there is a gas leak at home?  For more information on the safety and health aspects of living with anosmia, please visit the Safety Advice page.

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