The study found moderate health benefits across ages

In a recent study published in the journal Nature Human Behaviorresearchers conducted a meta-analytic study to estimate the effect size of touch therapies and to identify characteristics that influence their efficacy.

Touch is a crucial sense that develops in babies and is the first way humans connect with the physical and social environment. Touch therapies, including massages and kangaroo care, have been shown to improve mental and physical health, development and reduce anxiety. However, factors such as demographics, species, duration of contact, health outcomes, and the individual providing the touch influence its benefits. Previous meta-analytic studies have focused on specific forms of touch, study groups, and health outcomes, but have not found significant factors modulating the efficacy of a touch intervention. Understanding these characteristics is critical to designing treatments and improving population health.

Study: A systematic review and multivariate meta-analysis of the physical and mental health benefits of touch interventions. Image credit: Lighthunter / Shutterstock

About the research

In the current study, researchers conducted qualitative (systematic literature review) and quantitative (meta-analysis) studies to evaluate the impact of touch therapies on mental and physical health and to find factors that influence their efficacy.

Researchers examine whether and to what extent health outcomes are influenced by the dynamics of dyad touch (including objects, robots, or people, as well as the directionality and familiarity of touch), demographics (such as age, gender, or clinical status), means of delivery (t .ie type of intervention when touching or body part touched) and procedure (such as session frequency or duration). They also examined interactions between people, both with and without skin-to-skin contact. They conducted separate analyzes for neonates, children, and elderly individuals.

The team included 137 studies in the meta-analysis and 75 additional studies in the systematic review (n = 12,966 individuals) from the PubMed, Web of Science and Google Scholar databases between December 2, 2021 and October 1, 2022. The studies included touch treatments versus no-touch control groups, with different health outcomes as dependent variables.

Researchers excluded reviews, dissertations, studies assessing pleasantness ratings and neurophysiological responses after touch, records with missing data, and those published in languages ​​other than English. Two independent authors performed data screening and assessed risk of bias by study smallness, randomisation, consistency, productivity and attrition bias.

Results

From 85 studies, the researchers included 2,841 touch intervention recipients and 2,556 controls, and found moderately large effects for touch. Among newborns, 2,134 intervention recipients and 2,086 controls in 52 studies observed similar effects for mental and physical outcomes. Assessment of specific outcomes revealed lower benefits for heart rate and sleep parameters, moderate benefits for negative and positive affect, systolic and diastolic blood pressure, mobility, and cortisol reduction, and greater improvements for depression, trait, and state anxiety. pain and fatigue.

Post-hoc analysis found that state anxiety, pain, trait anxiety, and depression influenced more than heart rate, respiration, and sleep parameters. The reduction in anxiety and discomfort in the condition is more significant than the reduction in negative affect. The benefits of pain symptoms outweigh the benefits of pleasant effects. Touch confers more benefits on cortisol release than heart rate parameters, especially in women. In infants, health outcomes such as liver enzymes, cortisol, temperature regulation, weight gain, and respiration had moderate to significant effects.

Touch therapies using objects or robots have been shown to have comparable physical but smaller mental health benefits. Elderly clinical cohorts report more mental health benefits from skin-to-skin contact than healthy individuals. However, maternal contact is more beneficial for babies. The study suggests that researchers should tailor touch types to the context of each touch session. More touch sessions improved outcomes for adults, with beneficial relationships reported for anxiety, sadness, and pain. Touching the head, such as a face or scalp massage, provides more health benefits than hand and body contact.

One-way touch has more health benefits, especially mental health benefits. The researchers also examined animal health outcomes in 19 studies, focusing on rodents such as rats, mice, macaques, cats, lambs and coral reef fish. The touch treatment was largely stroking and tickling, with 71% of results favorable for parameters related to mental health and 82% demonstrating beneficial effects on physical health.

Conclusions

Based on the study results, touch therapies benefit physical and mental health with a modest effect. They relieve pain, sadness and anxiety in adults and children while increasing weight gain in babies. Massage and other forms of touch have similar health benefits. Touch therapies can help regulate serum cortisol, increase body weight in newborns, and reduce pain, depression, and anxiety in adults. However, it is critical to consider study bias and blinded experimental settings. The frequency of treatments is also important, with more sessions improving results and reducing pain in adults. The study showed negative correlations between cortisol and blood pressure in adults due to the habituation effects of touch on the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis.