Childhood adversity linked to altered physical response during stress

Experiencing neglect, abuse, or household dysfunction during childhood may alter how the body physically responds to psychological stress later in life. A study of 159 undergraduate students published in Psychophysiology found that individuals with a history of childhood adversity showed a noticeably muted blood pressure reaction during a stressful task and a slower return to normal levels afterward. These altered physical responses could help explain how early trauma contributes to a higher risk of heart disease in adulthood.

Adverse childhood experiences include potentially traumatic events that occur before age 18. These events range from physical and emotional abuse to household challenges like living with a family member who has a mental illness or substance use disorder. Public health experts have repeatedly linked these early traumas to a host of negative physical health outcomes, including an increased risk of developing cardiovascular disease.

Researchers have proposed several biological pathways to explain how adversity in childhood translates to heart problems decades later. One prominent focus is the autonomic nervous system, which controls the body’s unconscious physiological functions, including the fight-or-flight stress response. When a person encounters an acute stressor, this system typically mobilizes resources by increasing heart rate and blood pressure.

Historically, scientists assumed that only an exaggerated, overly intense stress response was harmful to the cardiovascular system. But recent evidence suggests that a blunted, or unusually low, physiological reaction to stress is also a sign of a dysregulated system. A failure to mount an adequate physical response to a challenge is associated with deficits in brain areas that regulate motivation and behavior.

Some scientists suggest this blunted response is an evolutionary adaptation. Children raised in persistently threatening environments might develop a lowered sensitivity to stress as a short-term survival strategy, protecting their bodies from being constantly overwhelmed. Yet in the long run, this suppression can impair the body’s physiological flexibility.

Aisling M. Costello, a psychology researcher at Schreiner University, along with Alyndra Plagge of Trinity University and Adam O’Riordan of the University of Texas San Antonio, designed a study to test these theories. They wanted to see if a history of childhood adversity predicted how participants reacted to, and recovered from, a sudden psychological stressor.

The researchers recruited 159 young adults for a single laboratory visit. To ensure baseline health behaviors did not skew the physiological measurements, the participants were asked to avoid alcohol and vigorous exercise for twelve hours prior to the study, and to abstain from caffeine and food for two hours beforehand.

During the experiment, the participants sat in a chair while an automated blood pressure cuff monitored their cardiovascular signs. The researchers tracked the participants’ physiological states during a ten-minute resting period to establish a baseline.

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The team measured several cardiovascular metrics, including heart rate, systolic blood pressure, and diastolic blood pressure. Systolic blood pressure is the pressure in the arteries when the heart muscle contracts. Diastolic blood pressure is the pressure in the arteries when the heart rests between beats.

Next, the participants filled out a questionnaire assessing how psychologically stressed they felt at that exact moment. Then, they completed a modified version of the Trier Social Stress Task.

This task is designed to be psychologically demanding. Participants were instructed to mentally subtract the number 13 from 1,022 and state their answers aloud. They had to keep subtracting 13 from each new answer for a total of six minutes while two research assistants stood by, observing them. If a participant made a math error or took longer than ten seconds to answer, the observers instructed them to start over from the beginning.

Immediately after the math task, participants rated their psychological stress levels again. Finally, the participants sat quietly for a 15-minute recovery period while the automated cuff continued to take blood pressure and heart rate readings.

Participants also completed a standard ten-item survey that measured their history of adverse childhood experiences. The scores ranged from zero to ten, tallying different categories of early life trauma.

The mental arithmetic task worked as intended. Across the entire group, the participants reported feeling more stressed after the task. Their physiological measurements also spiked, showing marked increases in heart rate and blood pressure during the six minutes of mental math.

When the researchers factored in the participants’ history of early trauma, a distinct pattern emerged. Participants who reported a higher number of adverse childhood experiences demonstrated notably lower systolic and diastolic blood pressure spikes during the stress task. Their bodies simply did not mount the same physical response as those who reported fewer adverse experiences.

The researchers did not find this blunted response across all metrics. A history of childhood adversity did not predict heart rate reactions or mean arterial pressure, which is an average measurement of blood pressure over a single cardiac cycle.

In addition, the level of childhood adversity did not predict how subjectively stressed the participants felt. Even though their blood pressure responses were muted, participants with more childhood adversity reported similar levels of psychological stress as their peers.

The researchers also examined the 15-minute recovery period. The ability to return to a baseline state quickly is a sign of a healthy, adaptable cardiovascular system. The study revealed that participants with more childhood adversity experienced poorer recovery in their diastolic blood pressure. Their numbers lingered above baseline levels longer than those with lower adversity scores.

The researchers pointed out a few limitations to their work. Because the study relied on a cross-sectional design, it captured a snapshot in time. This type of analysis cannot prove that early childhood experiences directly caused the altered blood pressure responses.

The participants were also required to remember and report events from their childhoods, which introduces the possibility of memory biases. The sample itself consisted of college students who, on average, reported relatively low levels of severe childhood adversity. The physiological patterns might look different in clinical populations or older adults.

The study also did not screen for current mental health conditions like depression or anxiety. Since these conditions are common in young adults and can influence cardiovascular health, future researchers may want to track these variables to see how they impact physical stress responses.

Finally, the researchers adopted a conservative statistical approach by removing a few extreme data outliers from their primary analysis. These specific individuals had physiological readings that fell massively outside the normal range. When the researchers ran a secondary test that included these rare extremes, the association between early adversity and systolic blood pressure reactivity was not statistically significant.

Despite these limitations, the findings align with a growing body of evidence linking early life environments to long-term physical health. The results suggest that adverse childhood experiences might shape how the cardiovascular system manages and recovers from acute psychological stress.

The study, “Adverse Childhood Experiences Are Associated With Blunted Cardiovascular Reactivity and Poorer Recovery From Acute Psychological Stress,” was authored by Aisling M. Costello, Alyndra Plagge, and Adam O’Riordan.