Fact Friday 3 – Are Women more tolerant to pain?

Chris my friend and partner in crime as regards “Saturday – sports injuries sessions” at spinalsolutions Osteopathic Clinic in Birmingham, works very deep with her soft tissue techniques . The pain is sometimes intense depending on the state of the tissues in question Sometimes wives request to attend the session when their husbands are being treated as they have arrived together . Generally they are driven to tears of joy and laughter , as their husbands wince on our treatment table at the hands of a 60 year old woman . Of course there is a private joke that exists amongst most couples about the pain tolerance of men vs women, it becomes competitive ( at least to the men – its natural for us to compete). The general assumption seems to be that men are less tolerant than women because of natural adaptations that prepare a woman for childbirth. Perhaps though theres ‘comedy ‘ quality in men as ‘wimpy ‘buffooons or there is a desire to peel away the veneer of the ‘hunter gatherer ‘ and reveal the wimp beneath. . Whats the word on this matter?. When it comes to pain tolerance who are the wimps men or women? Firstly a little revision on pain. It appears we need pain , those born without it are suffering from a rare condition called ‘congenital insensitivity to pain’ Great! You might say no more pain , no more toothache or backache etc – whoopee!!! . Or perhaps not ? Without the ability to detect pain there would be the inability to detect injury thus causing further damage if injury is incurred .People who suffer from this have damaged joints and many other injuries that lead to an early death . So what causes pain ? Anything in the world that causes a reaction is called STMULI – when there is DAMAGE or a THREAT to damage then there is PAIN . The ‘STIMULI’ can be divided into several types:

MECHANICAL – Strong pressure , Pinch, Squeeze, Twist

THERMAL – Hot , Cold

ELECTRICAL – self explanatory

CHEMICAL eg acid

VISCERAL – inside your body

Special RECEPTORS in the skin and organs called NOCIOCEPTORS these are nerve endings that transmit through free nerve endings connected to small myleineated A and unmyleinated C nerve fibres ( these are lacking in those with ‘congenital insensitivity to pain’ ) So pain can be described as a NOCIOCEPTION process ( nocioception by the way is the latin for HURT). There are several steps in the NCIOCEPTION process: CONTACT WITH THE STIMULUS RECEPTION – nerve endings. TRANSMISSION – nerve sends the signal to the Central Nervous System PAIN CENTRE RECEPTION – The brain recieves the information for processing and thus ACTION. From the point opf pain , the nerves travel to the spine to a nerve centre called the dorsal root ganglia (bit like a junction box in the electrical system) . When they join the spine here they will make immediate connections and connections one or two segments above or below in the spine . A new set of neurons ( like wires) travel from here up the spine this specailsed tract is called the SPINOTHALAMIC TRACT. Itsa superhighway for the pain sensations, they tehn travel up the spine through the medulla and joinn the brain at the THALAMUS the brains relay centre. From the THALAMUS they then relay to various areas of a specail area in the brain called the SOMATOSENSORY CORTEX – NOTE THERE IS NO SINGLE PAIN CENTRE IN THE BRAIN Once the brain undersatnds the STIMULI as pain then it may influence muscles to RETREAT from the STMULUS . However several observations lead scientists to think that the brain can influence pain perception : The pain from a cut on your hand eventually subsides or reduces to a lower intensity If you conciously distract yourself, you dont think about the pain and it bothers you less. People given placebos for pain control often report that the pain ceases or diminishes These observations indicate that pain influencing patways must exist from the brain downward. If we begin with the childbirth story , the pain experienced here is described at being related to the uterine contractions and the stretching of tissues invoved in the further process of crowning of the baby’s head in relation to the pelvis during labour. Secretion at this time of the hormone oxytocin may contrute to feelings of comfort and elation which comptete with any anxiety at this time . The joy of a first child may indeed create descending influence in the brain through the spinal cord which combat pain .

Much of the evidence seems to suggest that in fact despite the expected outcome of women having a natural tendency to resist pain , mostly there a processes related to the hormone Oestrogen that promote greater sensitivity to pain. The fact that there is a difference is becoming clearer and is the subject of much research . It has been known for a while that some ‘opoid analgesics’ are more effective in women than men. Opoid decrease pain by acting on specail receptors located on nerves transmitting painful sensations. Therea re also special receptors in the brain and spinal cord called mu, delta, and kappa and the numbers of these dont differ dramatically in men or women. Research conducted at State University of New York have discovered that the the same major types of opoid receptors interact differently depending on sex. In the lab, female animal brains were found to have five time s more of the mu-kappa opoid receptors than their male counterparts. Mu -kappa amounts were four times higher when their levels of oestrogen and progesterone were at their peak. In addition researchers found that both osetrogen and progesterone are critical in the formation of the mu-kappa opoid receptor complexes. It thus follows that drugs that act on mu-opoid and kappa – opoid receptors are more effective in treating pain in women than men. So what about chronic pain? Whats the difference here ? We mentioned female hormones and the differenc eagain is here with men having TESTOSTERONE which has no major monthly cyclic effects on the male body. Both hormones are associated with the production of natural pain killers and as mentioned for women these hormones affect special receptors for pain. Estrogen fluctuation is related to the menstrual cycle thus a womans natural response to pain is not as reliable as a mans . Research conducted at Stanford Hspital and clicins in a study of 11,00 men a and women concluded that women feel pain more intensely than men . Self reporting was invited using patient reported pain scores . Patients were asked rate their pain on an 11 point scale with 0 representing “no pain” and 11 signifying the worse pain managable. The study included 47 disorders – from cancer to back conditions and infectious diseases and more than 161,000 patient reported scores. Overall women were more likely to indicate higher pain than men say lead author Dr Atul Butte , chief of systems medicine in the department of paediatrics at stanford University School of Medicine . It seems that the ‘story ‘ here again is hormones it seems that osestrogen can also dmapen the activity of pain recpetors helping them to tolerate higher levels of pain , that means they may be more susceptible to pain in low oestrogen parts of the cycle . This would suggest there are different experiences to pain for women in general. Of course response to pain isnt all about receptors ,role pereceptions and society norms may also influence perception or reporting . Are their any differences in the brain ? Researchers at the University of California Los Angeles (UCLA) found that in mens brains analytical areas showed greater activity. Using a population of IBS suffers 26 women and 24 men received brain scans by positron emission tomograpphy (PET) while they experienced a small amount of pain. Differences were observed, The female brain showed greater activity in the limbic regions which are emotion based . In men cognitive regions or analytical centers showed greater activity. Dr Bruce Nabiloff , clinical professor of psychiatry and behavioural sciences at UCLA suggested the reason may be related to our primitive past, the evolution of gender differences being based on men having to make more ‘fight or flight’ decisions thus analytical and women being concerned with protection of the children which is mor emotional . So current research seems to suggest that women are more sensitive to pain and at time may display a higher or lower threshold . However the research doesnt categorise wimps from non wimps. Tolerance would also be dependant on life experience and other factors of nurture. And as far as our Saturdays go the men complain more than women and speaking from mans point of view – MUMMY!!!