Why Human Subjectivity Matters in Physical Health Outcomes
In recent years, medicine has been on a rampage to correlate measurable physiologic markers with health outcomes. For instance, low heart rate variability (HRV) has been associated with a higher risk of death from any cause. And walking an additional 1000 steps per day can help lower the risk of all-cause mortality. Also, eye movement characteristics can be used as biomarkers of Parkinson’s disease, Alzheimer’s disease, schizophrenia, and other diseases.
Despite these seemingly promising predictors of health outcomes, the chase after biometrics—these physiologic markers—is fraught with “fine print” exceptions that complicate their value. For instance, HRV has chaotic signatures that need to be considered for its proper use. And while the number of steps per day may impact mortality, the intensity of steps may not be as important, though other studies have demonstrated that exercise intensity matters.
In the search for objective measurable correlates, these complexities are often missed, and the more subjective aspects of the human condition have been relatively ignored despite indications that they may play significant roles in health outcomes and mortality.
Social relationships and risk of illness and death: For instance, people with stronger social relationships have a 50% increased likelihood of survival. And when many complex aspects of social relationships were considered, the odds of mortality increased by 91% among the socially isolated. In one study, a higher degree of social integration was associated with lower risk of physiological dysregulation in both early and later life. And social isolation increased the risk of inflammation by the same magnitude as physical inactivity in adolescence. Also, the effect of social isolation on hypertension exceeded that of clinical risk factors such as diabetes in old age.
Purpose in life and risk of illness and death: In people who are over 50 years of age, having a greater purpose in life protects against premature death from any cause, and also impacts death from heart and blood-related conditions too. And another study showed that age does not necessarily matter. Ten prospective studies with a total of 136,265 participants demonstrated that having a higher purpose in life was associated with reduced all-cause mortality and cardiovascular events.
The arts and risk of illness and death: Music can calm neural activity in the brain, which may lead to reductions in anxiety, and it may help to restore effective functioning in the immune system partly via the actions of the amygdala and hypothalamus. Visual art correlates with improved clinical outcomes, including better vital signs, diminished cortisol related to stress, and less medication needed to induce sleep. And emotional writing can influence frequency of physician visits, immune function, stress hormones, blood pressure, and a number of social, academic, and cognitive variables too.
Subjective age and risk of illness and death: The older you feel (and not are), the more likely it is that you will die. For example, feeling approximately 8, 11, and 13 years older was related to an 18%, 29%, and 25% higher risk of mortality, respectively. When people feel older, they have greater disease burden, physical inactivity, functional limitations, and cognitive problems too. Importantly, it’s not that the optimism and positive psychology of expecting to live longer improves your health. Subjective life expectancy plays a more independent role in impacting how long you live.
Conclusion: From these analyses, it is apparent that more subjective aspects of human life can impact how long you live. High quality social relationships, higher purpose, the arts, and subjective life expectancy all play a role in whether you get ill and how long you live.
Given these signals on the importance of the mroe subjective aspects of the human condition, machine learning-based predictive paradigms and medical interventions should incorporate the more subjective aspects of being human when aiming to improve quality of life and longevity.