On: The pervasive effect of stress – is it killing you?

Episode: 51

Date: April 2019

Background: Neuroendocrinologist.

Key Subjects:

• Dual hormonal pathway triggered by stress stimulus:
  • Immediate response – adrenalin:
    • Triggers activation of parasympathetic nervous system.
  • Secondary response – cortisol:
    • Continues parasympathetic response (elevated blood glucose).
    • Shuts down digestion, metabolism, growth hormones, reproduction.
    • See also (“The Hour Between Dog and Wolf“)
• Narrow window of optimum level of cortisol, depends on:
  • How much is released (too much or too little not good).
  • How responsive you are to certain levels (type of receptors; individual biological set-points).
• Correlation between (perception of) social status and stress:
  • Humans play roles in multiple hierarchies (work, family, hobbies).
  • Typically, where they rank highest is the most meaningful to them.
• Correlation between personality and stress:
  • Regardless of rank, combination of genetics and environment influences how you perceive certain potential stress stimuli.
  • Can be seen in size and activity of amygdala.
• Three brain systems:
  • Brain stem: autonomic system (breathing, body regulation).
  • Limbic system: emotions, survival activities (food, sex) (amygdala, hippocampus, thalamus).
  • Cortex: executive function, thinking, reasoning, planning.
• “Optimal” levels of stress stimulate:
  • Delivery of energy, oxygen, synapses, memory retention.
• Relationship between (mental) health and income:
  • Level of income explains large part of variability in health.
    • Not necessarily or only due to lower access to health care for poor.
    • Subjective view of socio-economic status is at least as good a predictor of health as income.
  • Not necessarily about being poor (only), but feeling poor.
    • What makes you feel poor: awareness of inequality.
  • What makes you aware of inequality.
    • Constant reminders in (social) media.
  • Current (media) environment has potential to amplify difference.
    • Causing wider spread chronic stress.
• Chronic stress:
  • Strengthens (grows) the amygdala (fear, anxiety, aggression).
  • Weakens (shrinks) the hippocampus (memory).
  • Weakens the frontal cortex (impulse control, long-term planning, empathy).
• Fixes for chronic stress:
  • Whatever you do (exercise, meditation), do it regularly rather than one-offs.
• Genetic basis for stress, depression:
  • Direct linkages between genes and depression unclear.
    • Similar to other complex behavior.
  • Likely that certain genes make you more vulnerable to how you react to external stimuli.
• Stress and sleep (see “Sleep“):
  • Cortisol spikes about one hour before sleep.
  • Cortisol inhibits release of melatonin.
    • More difficult to fall asleep, less brain restoration.
  • Chronic stress causes cortisol to stay high throughout.
    • Lower sleep quality.