Final answer:
Aerobic exercise counteracts depression by increasing the production of endorphins in the brain, which are chemicals that can create a euphoric state known as 'runner's high.' Regular exercise also boosts serotonin levels and improves mood and self-esteem, contributing to its antidepressant effects.
Step-by-step explanation:
Aerobic exercise, such as running, may counteract depression in part by increasing the activity of endorphins in the brain. During physical activity, endorphins are released, which are known to help in reducing the perception of pain and can lead to a feeling of euphoria, often referred to as 'runner's high.' While there is evidence to suggest that endocannabinoids also play a role in this, the release of endorphins is widely recognized as contributing to the positive effects of exercise on anxiety and depression.
Furthermore, regular aerobic exercise has been shown to induce both short- and long-term effects on mood and emotional states. It acts as an antidepressant and euphoriant in the short term, while consistent exercise leads to improvements in mood and self-esteem over time. Moreover, exercise increases levels of neurotransmitters like serotonin, which are associated with mood regulation and play a role in countering depressive symptoms.