Научное исследование подтверждает влияние тактильного контакта на выработку окситоцина и укрепление иммунитета

I have had exactly three professional massages in my life. The first was last year: a couples massage for my wife and I at a resort in Vietnam. She tells me I fell asleep and snored, but I’m pretty sure I was just really, really relaxed. The other two were this year, with the first being a gift from our kids on our 25th anniversary. The most recent was, well, just a treat because I know how much my wife loves it, and I enjoy the shared experience. I doubt I’d ever get a massage on my own, however, because although my wife loves a deep-tissue massage, I don’t, really. I’m not sure I really enjoy being touched by a stranger, and I don’t understand the ecstasy of feeling like someone’s stabbing an elbow bone-deep into my thigh. Let’s ignore the elbow-stabbing for a moment and reflect on touch more broadly. For the purpose of this column, I’m talking about consensually agreed touch by another person. In 2020, researchers at Goldsmiths University, London, collaborated with the BBC on “The Touch Test”, a global survey of people’s attitudes to being touched. Almost three-quarters of respondents reported feeling positive about being touched, which also means more than a quarter felt negatively. Half said they would like more touch in their lives (and only 3% said they already had too much, thanks). It’s worth bearing in mind there was a lot going on in 2020, but this is in the ball park for other research on touch from before physical distancing. There’s good reason to think being touched is beneficial for us. There’s reliable evidence being hugged is good for anxiety and depression. Analyses of multiple studies show robust evidence that rhythmic stroking reduces cortisol levels and releases oxytocin. Cortisol is a hormone that gets released as part of our response to stressful situations. Cortisol (and stress in general) suppresses the immune system, but research shows rhythmic touch stimulates immune functioning. How does this work? It’s something to do with a particular type of touch receptor called a C-tactile afferent fibre. These nerve fibres differ from the other nerve fibres in our skin because they’re unmyelinated. Myelin is a fatty layer that wraps around many of our nerves, a bit like insulation around an electrical cable, and speeds up signal transmission. But signals move much more slowly through C-tactile fibres, and they’re primed for particularly slow and light touch. A swift poke or a hard rub won’t trigger them to send comfort and safety signals to the brain. Similarly, they’re sensitive to touch from things that are around human skin temperature – they don’t fire as much from a cup of tea, or an ice cube. The release of oxytocin through rhythmic touch again has something to do with C-tactile fibres. When they’re triggered, they send signals to the brain that activate little oxytocin-producing factories (neurons). Oxytocin has received a lot of buzz as a “love” hormone because it plays an important role in labour and lactation and appears to promote trust and empathy. I was interested to learn that while the unmyelinated C-tactile fibres are implicated in oxytocin production, oxytocin is also important for promoting nerve myelination. It limits the damage to myelinated nerves when the brain is traumatised or inflamed, then gets to work on organising damage repair. Yep, it’s a brain first responder. So, I’ve learnt a lot, including why I’m not wild about being pummelled on the massage table: because a hard pummelling doesn’t trigger my C-tactile fibres. Why does my wife enjoy the pummelling? That will have to wait for a later column.