Victoria Booth
Stress
Question Received:
Response:
19th December 2024
This is something of a speculative answer until I can find a better explanation – perhaps the heightened activity of the bladder is due to the increased amounts of adrenaline and noradrenaline circulating in the bloodstream in response to the cold? These hormones are released from the adrenal medulla as part of a generalised stress response and promote energy mobilisation and the generation of additional heat: adrenaline and noradrenaline stimulate the liver to release glucose into the blood and cause a general rise in the basal metabolic rate. We usually assume that during an arousal response of this sort the activity of the urinary system will diminish – there is renal vasoconstriction and generally less urine is produced when we are under stress, so therefore it seems unlikely that the increased urge to urinate is due to increased output by the kidneys. As the wall of the urinary bladder is largely composed of smooth muscle (the detrusor muscle), it is possible that muscle tone in the bladder wall increases in response to the circulating catechol amine hormones so that pressure in the partially-filled bladder rises more than usual. (We need to know which hormone receptors are carried by these muscle fibres.) Such a pressure increase might cause the nervous system to come to the erroneous conclusion that the bladder is much fuller than it actually is, and give a feeling of urgency. Or could it be that extra cup of hot tea before going out?
