The relationship between emotional states and immune function is a subject of interest in psychoneuroimmunology, a field of study that explores how psychological factors, the nervous system, and the immune system interact.
Emotional states have been shown to influence immune function directly. Stress and depression can suppress the immune system, making the body more susceptible to infections and slower to heal from injuries or surgeries. On the other hand, a positive emotional state can boost the immune system, leading to better health outcomes.
Here's a detailed look at some of the mechanisms explaining why emotional states can influence immune function.
When the body experiences emotional stress or distress, it releases neurotransmitters and stress hormones like cortisol and adrenaline. These biochemicals have a direct influence on various bodily functions, including the immune system. For example, cortisol can suppress the efficacy of certain immune cells, reducing their ability to fight off infections or disease.
The autonomic nervous system (ANS), responsible for involuntary functions like heart rate and digestion, also plays a role. The ANS has two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). Emotional stress activates the SNS, often referred to as the "fight or flight" system, which can suppress immune function as the body allocates resources to immediate survival needs. On the other hand, the PNS, also known as the "rest and digest" system, can enhance immune function and is activated during states of emotional wellbeing.
Emotional stress can trigger inflammatory responses in the body. While inflammation is a normal and necessary process for fighting off pathogens, chronic inflammation is harmful and has been linked to various diseases. Chronic emotional stress can contribute to sustained levels of inflammation, weakening the immune system over time.
Negative emotional states can also lead to behaviors that indirectly impact the immune system. For instance, people who are stressed, anxious, or depressed are more likely to engage in unhealthy behaviors like poor diet choices, lack of exercise, or substance abuse, all of which can weaken immune function. Conversely, a positive emotional state is more likely to encourage behaviors that support immune health, such as adequate sleep, regular exercise, and a balanced diet.
Prolonged exposure to psychosocial stressors like isolation, low social support, and high levels of daily life stress can take a toll on the immune system. These stressors have been shown to reduce lymphocyte proliferation and natural killer cell activity, both essential components of the immune response.
Positive emotional states such as happiness, relaxation, and mindfulness have been shown to increase levels of immunoglobulin A, an antibody that plays a crucial role in the immunity of mucous membranes lining the gut and respiratory tract. Practices that improve emotional wellbeing, like mindfulness and meditation, have also been found to increase the production of T-cells, another crucial element of the immune system.
In an experiment [need reference], people in one group where asked to close their eyes and imagine for 5 minutes someone they loved. In the second group, people where asked to imagine for 5 minutes someone they hate (or perhaps something they fear). In both groups, the level of a certain chemical related to the immune system was measured. It was found that in the first group, the level increased quite significantly, and it took about 2 hours for the level to return to base level. In the second group, the level decreased quite significantly, and it took about 2 hours for the level to recover. And this is just 5 minutes! Imagine what are the effect of chronic stress on the body!!!