Even before lockdown, we were experiencing less human touch than ever before in history, partly because so many of us live apart from family and friends and partly through fear of inappropriate touch. Social distancing has meant that we now hold back from so many forms of physical interaction that we took for granted previously: hand shaking, hugging, placing a reassuring hand on an arm or shoulder. It is sobering to think that many of us now touch our screens more than we do other humans.
Touch is a biological necessity for our physical and emotional wellbeing. For example, a lack of touch in infancy leads to cognitive deficit, and touch at any age can improve resilience to stress. We also need to be able to respond rapidly to potentially life-threatening stimuli, such as fire or sharp objects. To that end, we have two types of touch receptors: fast and slow.
Fast Touch Receptors
The fast receptors have myelinated sheaths, which allow nerve impulses to be transmitted rapidly to the brain for an immediate response to whatever they detect in the outside world, whether that is to pull your hand away from a hot object or to hold more tightly onto a wet glass that is slipping out of your hand. These fast receptors are what enable you to detect, among other things, temperature, texture, pressure and stretch. They are found all over the body, but are most dense on the glabrous (hairless) skin on the digits and lips, and also on the palms of the hands and the soles of the feet.
Slow Touch Receptors
The slow touch receptors (known as C-tactile afferents or CTs) lack the myelinated nerve sheath and so it takes longer for an impulse to reach the brain (about 1m/second). They are only found on hairy skin and are sensitive to pleasant touch, such as a hug or stroking. Research has shown that the optimal stroking speed to stimulate CTs is 3-5cm/s, which is the speed that most of us would use instinctively to soothe a loved one, to show affection or for sensual touch. CTs are linked to our emotional response to touch and are present in the skin of all social mammals, i.e. those that respond to bonding (affiliative) contact between one individual and another.
Some of the benefits of affiliative human touch are lower heart rate, lower blood pressure, reduced cortisol levels, greater resilience to stress and improved immunity, which is why massage and reflexology can also promote the same effects.
Hopefully an awareness of this often overlooked sense will give you a greater appreciation of it and encourage you to use it more, where it is safe and appropriate to do so. And if human touch is not available to you or is limited for whatever reason, you can still stimulate the slow touch receptors in your skin with pleasant sensations such as a warm bath, the warmth of the sun on your skin or the wind on your face. Exercise too, especially if done outdoors, can help compensate for a lack of touch.
If you would like to learn more about this sense, I can recommend reading the chapter on touch in Dr Rangan Chatterjee’s book The Stress Solution and listening to his podcast interview with Professor Frances McGlone, a leading researcher in human touch. Coincidentally, psychologist Claudia Hammond explores the ‘Anatomy of Touch’ in her new series on Radio 4.