Heart, Brain, and Body

I  February. Yes, because of snow and skiing and the short days that last ever-so-slightly longer. And, because, of course, Valentine’s Day. But most recently, and consistent with that theme, because February is American Heart Month.

The National Institute of Mental Health (NIMH) is all about the brain (and I do  February, too), but in reality, the brain can’t do much without the heart. And it turns out there are a lot of connections between heart health (and illness) and brain health (and illness). So, in honor of American Heart Month, I thought I’d tell you about NIMH’s research activity at the intersection of the heart, brain, and body.

Let’s start with one of the more recently appreciated connections between the heart and the brain: stress. Of course, we know that stress can adversely affect heart health and brain health. But did you know that the way the heart beats is itself a signal of stress? The heart has a more-or-less regular rhythm. For most of us, this rhythm averages somewhere around 60 beats per minute, or about once every second; it goes up with exercise and down with relaxation or sleep.

Interestingly, stress affects the heart too, not so much by changing how fast the heart beats, but by changing how regularly it beats. You see, the rhythm of our heart rate isn’t perfect—the time between beats is sometimes more than one second and sometimes less. This is called heart rate variability (HRV), and this variability is totally normal—it is the product of the body continuously responding to changes in one’s immediate situation. But stress reduces HRV, and this reduction has been associated with adverse outcomes. A recent NIMH-supported study  by Jonas Miller, Ph.D., Ian Gotlib, Ph.D., and colleagues looked at the association between HRV and adverse mental health consequences of the COVID-19 pandemic. As part of a longitudinal study of teenagers, they measured HRV years before the pandemic. Then, during the pandemic, they asked these same teens about their emotional health. The researchers found that teens with lower HRV before the pandemic had more severe emotional responses to pandemic-related stressors.

Heart health is also directly linked to mental disorders. Numerous studies have suggested that the risk for depression is higher in those with cardiovascular disease and vice versa. In the past year, two papers have emerged from NIMH-funded research underscoring this bidirectional relationship and expanding it beyond depression. Qing Shen, Ph.D., Unnur Valdimarsdóttir, Ph.D., and colleagues studied siblings  without a history of mental illness, one of whom was newly diagnosed with cardiovascular disease. The researchers used national health care records to look at subsequent diagnoses of new mental illnesses in the siblings. They found that the risk for mental illness was nearly three times higher for siblings with cardiovascular disease in the first year after their diagnosis. At the same time, Stephanie Hooker, Ph.D., Rebecca Rossom, M.D., and colleagues found  that among patients in primary care, those who screened positive for depression had significantly elevated risk factors for cardiovascular disease, with a predicted risk over 50% higher than for patients without depression. Together, these findings point to the importance of ensuring adequate mental health and cardiovascular care for patients with either condition.

Individuals with serious mental illness (SMI), and especially those with schizophrenia, deserve particular attention when it comes to heart health. People with SMI have much higher mortality rates than the general population, and much of the increased risk can be attributed to cardiovascular disease. Accordingly, NIMH funds research aimed at how to reduce cardiovascular risk in individuals with schizophrenia. In one such study , researchers Mark Hawes, M.S.W., Leopoldo Cabassa, Ph.D., and colleagues examined the factors that led to successful cardiovascular risk reduction in people with SMI enrolled in programs aimed at supporting healthier lifestyles. They found that programs that imparted specific knowledge and skills that helped people make healthier decisions and encouraged them to continue using these skills were the most successful at lowering the risk for cardiovascular disease.

Heart health and mental health are amenable to properly designed treatments. It takes clear, specific instructions; encouragement and support; and sticking with what works. And that’s a good lesson to end on—one with a hopeful, heart-healthy outlook.

References

Hawes, M. R., Danforth, M. L., Pérez-Flores, N. J., Bochicchio, L., Tuda, D., Stefancic, A., & Cabassa, L. J. (2022). Learning, doing and sticking with it: A qualitative study on achieving clinically significant reduction in cardiovascular disease risk in a healthy lifestyle intervention for people with serious mental illness. Health & Social Care in the Community, 30(5), e2989–e2999. https://doi.org/10.1111/hsc.13744 

Hooker, S. A., O'Connor, P. J., Sperl-Hillen, J. M., Crain, A. L., Ohnsorg, K., Kane, S., & Rossom, R. (2022). Depression and cardiovascular risk in primary care patients. Journal of Psychosomatic Research, 158, Article 110920. https://doi.org/10.1016/j.jpsychores.2022.110920 

Miller, J. G., Chahal, R., Kirshenbaum, J. S., Ho, T. C., Gifuni, A. J., & Gotlib, I. H. (2022). Heart rate variability moderates the effects of COVID-19-related stress and family adversity on emotional problems in adolescents: Testing models of differential susceptibility and diathesis stress. Development and Psychopathology, 34(5), 1974–1985. https://doi.org/10.1017/S095457942100033X 

Shen, Q., Song, H., Aspelund, T., Yu, J., Lu, D., Jakobsdóttir, J., Bergstedt, J., Yi, L., Sullivan, P., Sjölander, A., Ye, W., Fall, K., Fang, F., & Valdimarsdóttir, U. (2022). Cardiovascular disease and subsequent risk of psychiatric disorders: A nationwide sibling-controlled study. eLife, 11, Article e80143. https://doi.org/10.7554/eLife.80143