Brief report: social skills, internalizing and externalizing symptoms, and respiratory sinus arrhythmia in autism.

Neuhaus et al. (2014) watched heart-rate variability (RSA) in boys with autism. They also scored each boy’s social skills, anxiety, and behavior problems.

The team wanted to know if lower RSA tied only to social trouble, or also to mood and behavior symptoms.

Boys with autism showed weaker RSA than typical boys. Lower RSA went hand-in-hand with poorer social skills.

The same low RSA also predicted anxiety and acting-out, even after social skill scores were held constant.

McCauley et al. (2018) pushed the timeline back: babies later diagnosed with ASD already had low RSA at four months. The autonomic signature starts early.

Morrison et al. (2017) widened the lens: low RSA also tracks how severe a child’s repetitive behaviors are. One heart measure maps onto several autism domains.

McQuaid et al. (2024) adds a twist: autistic youth show normal heart-rate and cortisol jumps during friendly play, but big spikes when they feel judged. RSA stays low across both settings, matching the 2014 picture of broad autonomic dysregulation.

You can treat low RSA as a red flag for both social struggles and internalizing or externalizing problems. When you see flat heart-rate variability during baseline, plan interventions that calm the body first—deep breathing, paced music, or brief movement breaks—then teach social or coping skills. Tracking RSA over sessions gives you an easy, non-verbal barometer of whether your regulation package is working.