Dr James Le Fanu: 25 January
Yawning is a neglected subject of enquiry, being commonplace enough and presumed to be of little significance – though is in its way quite fascinating. It is, to start with, a common physiological response to several quite different situations: tiredness, boredom, hunger, poor ventilation – while also being ‘infectious’, where ‘to see another yawn is also an invitation to yawn’.
Boredom-induced yawning is presumed to be primarily social, the physical expression to others of an inner emotion – an ‘involuntary signal’ to, for example, guests who have overstayed their welcome that it is time for them to go home.
By contrast, yawning when tired – frequently associated with stretching – is an attempt to regain a state of alertness. It was thought that this response was intended by nature as ‘an impulse caused by bad air in the lungs to awaken the respiratory organs into activity’. It is certainly plausible to suppose the intake of air when yawning would increase the amount of oxygen reaching the brain. However, this theory has been recently discounted in favour of the suggestion that the crucial factor is the stretching of the arms and respiratory muscles – revitalising the body by counteracting the loss of muscle tone that comes with tiredness.
Yawning is also undoubtedly a good thing, as illustrated by the adverse consequences for those in whom, for any reason, the reflex is inhibited. A Canadian professor of psychiatry describes the admittedly unusual case of a woman who dislocated her jaw when yawning. ‘She was unable to speak and experienced a lot of pain. Eventually her husband struck her on the right side of the jaw, returning it to its normal position and she was able to close her mouth again.’
She became so apprehensive of yawning she suppressed any incipient urge to do so by cupping her hand under her jaw. Deprived of the pleasure and relaxation that yawning brings, she became irritable and depressed.
THIS WEEK’S MEDICAL QUERY comes courtesy of a gentleman from Harrogate writing on behalf of his wife, who is in her early 80s. About three times a week immediately after breakfast, she ‘collapses in a heap’, but usually recovers by lunchtime. ‘We cannot expect too much at our age,’ he writes, ‘but the unpredictability of these episodes makes it difficult to plan anything in advance.’
The unusual feature here is the close relationship of the episodes of collapse to the first meal of the day. This is possibly the condition known as swallowing syncope, where stimulation of the nerves in the lining of the oesophagus by swallowing, induces a reflex slowing of the heart and with it, reduced blood flow to the brain. Writing in the New England Journal Of Medicine, a neurologist describes the case of a man who collapsed after consuming a carbonated drink. The neurologist organised for him to have tests after ingesting a can of cola, during which both heart rate and blood pressure fell dramatically – thus accounting for his symptoms. drjames@lady.co.uk
Boredom-induced yawning is presumed to be primarily social, the physical expression to others of an inner emotion – an ‘involuntary signal’ to, for example, guests who have overstayed their welcome that it is time for them to go home.
By contrast, yawning when tired – frequently associated with stretching – is an attempt to regain a state of alertness. It was thought that this response was intended by nature as ‘an impulse caused by bad air in the lungs to awaken the respiratory organs into activity’. It is certainly plausible to suppose the intake of air when yawning would increase the amount of oxygen reaching the brain. However, this theory has been recently discounted in favour of the suggestion that the crucial factor is the stretching of the arms and respiratory muscles – revitalising the body by counteracting the loss of muscle tone that comes with tiredness.
Yawning is also undoubtedly a good thing, as illustrated by the adverse consequences for those in whom, for any reason, the reflex is inhibited. A Canadian professor of psychiatry describes the admittedly unusual case of a woman who dislocated her jaw when yawning. ‘She was unable to speak and experienced a lot of pain. Eventually her husband struck her on the right side of the jaw, returning it to its normal position and she was able to close her mouth again.’
She became so apprehensive of yawning she suppressed any incipient urge to do so by cupping her hand under her jaw. Deprived of the pleasure and relaxation that yawning brings, she became irritable and depressed.
THIS WEEK’S MEDICAL QUERY comes courtesy of a gentleman from Harrogate writing on behalf of his wife, who is in her early 80s. About three times a week immediately after breakfast, she ‘collapses in a heap’, but usually recovers by lunchtime. ‘We cannot expect too much at our age,’ he writes, ‘but the unpredictability of these episodes makes it difficult to plan anything in advance.’
The unusual feature here is the close relationship of the episodes of collapse to the first meal of the day. This is possibly the condition known as swallowing syncope, where stimulation of the nerves in the lining of the oesophagus by swallowing, induces a reflex slowing of the heart and with it, reduced blood flow to the brain. Writing in the New England Journal Of Medicine, a neurologist describes the case of a man who collapsed after consuming a carbonated drink. The neurologist organised for him to have tests after ingesting a can of cola, during which both heart rate and blood pressure fell dramatically – thus accounting for his symptoms. drjames@lady.co.uk