The Science of huggu™

History of Pressure Therapy

The effect of tactile stimulation and in particular, pressure, has been studied since the 1960s, where studies have noted how touch pressure was beneficial to babies and animals¹. In the 1980s, Dr Temple Grandin pioneered a squeeze machine which she first used on herself to help treat her anxiety and panic attacks.

Grandin, herself diagnosed with Autism Spectrum Disorder, had noted that continual use of her machine not only helped to calm her anxiety and panic attacks, but over long term continual use, had also helped build her tolerance to being touched by other humans – as a child, she was averse to hugs and human touch².

Later in her academic and professional career, Grandin had then conducted studies of her squeeze machine on neurotypical adults. Several of the adult test subjects had found the pressure to be relaxing. The squeeze machine was also used by occupational therapists on children with autism and ADHD, as part of their sensory integration therapy, and had reported that the pressure was calming and helped to inhibit tantrums³.

Benefits of hugging

A study on the benefits of hugging have been studied and show that frequent hugs between test subjects are associated with lower blood pressure, heart rate, and higher oxytocin levels in premenopausal women⁴.

Alleviation of Stress

A review of the positive effects of massage therapy on individuals with various medical conditions and stressful situations found a relation between massage therapy on these individuals and decreased levels of cortisol and increased levels of serotonin and dopamine, which indicate alleviation of stress.

The conditions analysed included depression, pain syndrome, work-related stress, stress of ageing, and pregnancy stress⁵.

Pressure Therapy for Occupational Therapy

In a study of pressure therapy applied to individuals with Autism Spectrum Disorder (ASD), test subjects have been noted to have improvements in several areas. These included calmness, responsiveness, as well as happiness⁶.

Oxytocin and Dopamine Released in Response to Touch

Neurotransmitters such as oxytocin and dopamine released in response to touch may be regulating the limbic and reward areas of the brain.

Oxytocin has further been shown to be released during tactile contact while dampening stress and fear⁷.

Effects of Oxytocin

Oxytocin reduces anxiety, and promotes feelings of wellbeing and reward⁸.
Oxytocin increases calm and tolerance to pain and may decrease inflammation⁹.
Oxytocin induces powerful anti-stress effects by reducing the activity of the hypothalamic–pituitary–adrenal axis (a region in the brain that controls reactions to stress)¹⁰.
Oxytocin reduces some aspects of the sympathetic nervous system, and in doing so decreases the activity of the cardiovascular system¹¹.
Oxytocin also increases digestion by increasing the function of the parasympathetic nervous system¹².

Effects of Serotonin

Serotonin is a monoamine neurotransmitter that is involved in many processes in the body from cognitive ones like mood and memory, to physiological ones like digestion and organ development.

Serotonin is involved in the regulation of mood, and improves mood via promotion of stress moderation and patience¹³.
Serotonin contributes to increased cognitive flexibility¹⁴.
Serotonin contributes to focus, motivation, and confidence¹⁵.
Conversely, deficiency of serotonin or the inability to process serotonin induces depression¹⁶.

Effects of Dopamine

Dopamine is a phenylethylamine neurotransmitter which controls several different pathways in the brain.

One prominent role that dopamine plays is in the reward center of the brain. The release of dopamine is linked to feelings of reward and motivation¹⁷.
Dopamine is linked to feelings of pleasure, which is in itself an aspect of reward¹⁸.
Dopamine is linked to attention, another manifestation of reward¹⁹.
Deficiency in dopamine results in certain health conditions like Parkinson’s Disease and Attention Deficit Hyperactivity Disorder (ADHD).

^{1 GRANDIN, T. E. M. P. L. E. (1992). Calming effects of deep touch pressure in patients with autistic disorder, college students, and animals. Journal of Child and Adolescent Psychopharmacology, 2(1), 63–72. https://doi.org/10.1089/cap.1992.2.63}

^{2 GRANDIN, T. E. M. P. L. E. (1992). Calming effects of deep touch pressure in patients with autistic disorder, college students, and animals. Journal of Child and Adolescent Psychopharmacology, 2(1), 63–72. https://doi.org/10.1089/cap.1992.2.63}

^{3 GRANDIN, T. E. M. P. L. E. (1992). Calming effects of deep touch pressure in patients with autistic disorder, college students, and animals. Journal of Child and Adolescent Psychopharmacology, 2(1), 63–72. https://doi.org/10.1089/cap.1992.2.63}

^{4 Light, K. C., Grewen, K. M., & Amico, J. A. (2005). More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. Biological Psychology, 69(1), 5–21. https://doi.org/10.1016/j.biopsycho.2004.11.002}

^{5 FIELD, T. I. F. F. A. N. Y., HERNANDEZ-REIF, M. A. R. I. A., DIEGO, M. I. G. U. E. L., SCHANBERG, S. A. U. L., & KUHN, C. Y. N. T. H. I. A. (2005). Cortisol decreases and serotonin and dopamine increase following massage therapy. International Journal of Neuroscience, 115(10), 1397–1413. https://doi.org/10.1080/00207450590956459}

^{6 Bestbier, L., & Williams, T. I. (2017). The immediate effects of deep pressure on young people with autism and severe intellectual difficulties: Demonstrating individual differences. Occupational Therapy International, 2017, 1–7. https://doi.org/10.1155/2017/7534972}

^{7 Walker SC, Trotter PD, Swaney WT, Marshall A, McGlone FP. C-tactile afferents: cutaneous mediators of oxytocin release during affiliative tactile interactions? Neuropeptides. (2017) 64:27–38. 10.1016/j.npep.2017.01.001}

^{8 Uvnäs-Moberg K., Ahlenius S., Hillegaart V., Alster P. (1994). High doses of oxytocin cause sedation and low doses cause an anxiolytic-like effect in male rats. Pharmacol. Biochem. Behav. 49, 101–106 10.1016/0091-3057(94)90462-6}

^{9 Uvnäs-Moberg K., Bruzelius G., Alster P., Bileviciute I., Lundeberg T. (1992). Oxytocin increases and a specific oxytocin antagonist decreases pain threshold in male rats. Acta Physiol. Scand. 144, 487–488. 10.1111/j.1748-1716.1992.tb09327.x}

^{10 Uvnäs-Moberg K., Bruzelius G., Alster P., Bileviciute I., Lundeberg T. (1992). Oxytocin increases and a specific oxytocin antagonist decreases pain threshold in male rats. Acta Physiol. Scand. 144, 487–488. 10.1111/j.1748-1716.1992.tb09327.x}

^{11 Uvnäs-Moberg K., Bruzelius G., Alster P., Bileviciute I., Lundeberg T. (1992). Oxytocin increases and a specific oxytocin antagonist decreases pain threshold in male rats. Acta Physiol. Scand. 144, 487–488. 10.1111/j.1748-1716.1992.tb09327.x}

^{12 ibid; Uvnās-Moberg, K., Handlin, L., & Petersson, M. (2015). Self-soothing behaviors with particular reference to oxytocin release induced by non-noxious sensory stimulation. Frontiers in Psychology, 5. https://doi.org/10.3389/fpsyg.2014.01529}

^{13 Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: A tale of two receptors. Journal of Psychopharmacology, 31(9), 1091–1120. https://doi.org/10.1177/0269881117725915}

^{14 Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: A tale of two receptors. Journal of Psychopharmacology, 31(9), 1091–1120. https://doi.org/10.1177/0269881117725915}

^{15 Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: A tale of two receptors. Journal of Psychopharmacology, 31(9), 1091–1120. https://doi.org/10.1177/0269881117725915}

^{16 Carhart-Harris, R. L., & Nutt, D. J. (2017). Serotonin and brain function: A tale of two receptors. Journal of Psychopharmacology, 31(9), 1091–1120. https://doi.org/10.1177/0269881117725915}

^{17 Berke, J. D. (2018). What does dopamine mean? Nature Neuroscience, 21(6), 787–793. https://doi.org/10.1038/s41593-018-0152-y}

^{18 Schultz, W. (2015). Neuronal reward and decision signals: From theories to data. Physiological Reviews, 95(3), 853–951. https://doi.org/10.1152/physrev.00023.2014}

^{19 Schultz, W. (2015). Neuronal reward and decision signals: From theories to data. Physiological Reviews, 95(3), 853–951. https://doi.org/10.1152/physrev.00023.2014}