Touch has improved the physical and mental health of people of all ages
Based on a large systematic review and a multilevel meta-analysis, scientists have obtained evidence that any type of touch - be it massage, hugging or stroking - is almost equally beneficial to health. Neither age nor what we touch - another person, object or robot - played a special role.
Medics from the Ruhr University Bochum and the University Hospital Essen (Germany) together with colleagues from the Netherlands Institute for Neuroscience conducted a review and multilevel meta-analysis of a total of 212 studies. The aim was to confirm the hypotheses that touch helps to support mental and physical well-being. A paper with the results is published in the peer-reviewed journal Nature Human Behaviour.
"Touch is hugely important for many aspects of our lives. It is the first of all senses to develop in newborns and provides direct contact with the environment. In addition to our own experience of touch, we regularly receive touch from those around us, for example through hugs, kisses or massage (consensual)," the scientists noted.
The Covid-19 pandemic, which brought self-isolation and social distance, has prompted renewed thinking about how physical contact can affect our health and psyche. Researchers had previously concluded that interactions such as carrying a newborn in a "kangaroo" (or sling), where the newborn is positioned sitting up, with pelvic support and legs dangling over the sides, helps with growth and development, and protects against anxiety and stress throughout future life.
While there are already meta-analyses on this topic, they have focused on specific types of touch, cohorts, or specific health benefits, so the researchers decided to look at the issue more comprehensively. Specifically, they asked: do the positive effects depend on who and what is being touched, whether they are familiar or not, demographic factors (age/sex), and duration of exposure? The researchers looked at data for adults and children, including newborns. Animals were also wanted to be included in the animal review, but it turned out that there wasn't enough work in this area.
In total, the final sample included 212 studies with information on 12,966 participants of all ages. The analysis showed that the benefits were generally similar for measures of mental and physical health, except that in adults, touch had less effect on sleep and heart rate, moderate effects on diastolic and systolic blood pressure (the effect increased with age), mobility and cortisol levels (the so-called stress hormone), and significant effects on reducing levels of anxiety, depression, fatigue and pain.
In the case of newborns, the researchers found no correlation between touch and improved digestion or heart rate. However, the correlation ranged from medium to significant when it came to cortisol levels, liver and respiratory enzyme values, weight gain and body temperature.
The greatest mental health benefits came from touching other people rather than the object, while even robots and other objects could be touched to promote physical health. The type of touch - for example, massage, stroking, hugging - did not play a role in any of the cases, but body parts were important. Frequent (e.g., more massage sessions) and unidirectional touch had more favorable effects.
"Hand touching resulted in poorer mental health but benefited physical health. In addition, touching the head rather than the torso was beneficial for physical health. Consequently, facial or scalp massage may be particularly beneficial," the scientists noted.
The authors of the paper emphasized that their findings need to be double-checked in large studies with control groups. It is also necessary to understand whether the culture in which a person grew up plays a role.