
Social relationships are essential to our health. This article explores, backed by scientific findings, the positive effects of friendships on mental health, the cardiovascular system, the immune system, and life expectancy.
On July 30th, International Friendship Day is celebrated worldwide. It’s a great opportunity to reflect on the enormous influence friendships have on our mental and physical health. Studies show: those who maintain stable social connections live longer, healthier lives and enjoy greater psychological balance. Yet in the hustle and bustle of everyday life, friendships are often neglected.
Did you know that social relationships can have as strong an impact on your life expectancy as not smoking or engaging in regular physical activity?
It has long been proven that stable interpersonal relationships are more than just an emotional plus – they act as preventive protective factors for health and quality of life. American psychologist Julianne Holt-Lunstad found in a comprehensive meta-analysis that people with stable social relationships have a 50% lower risk of death than isolated individuals. [6]
The effect of social connectedness is thus comparable to key medical prevention measures: quitting smoking, balanced nutrition, or sufficient physical activity have similar effects on mortality. At the same time, social isolation is increasingly recognized as an independent risk factor in public health debates – on par with high blood pressure, obesity, or inactivity. [1,3,6,8]
Friendships are among the most stable sources of emotional support – and a vital protective system for mental health. Numerous studies show that stable social bonds are associated with lower risks of depression, anxiety disorders, and stress-related illnesses. Interaction with trusted people fosters belonging, emotional safety, and self-worth. [9]
Psychologically, friendships strengthen resilience: people with strong social support cope better with stress, recover faster from crises, and show reduced stress reactivity. Simply perceiving that one is not alone reduces subjective stress and improves stress processing through neurobiological mechanisms (oxytocin release, reduced amygdala activity). [4,5]
Social bonds also promote a stable self-image: reciprocal validation, feedback, and emotional reflection reinforce a positive self-concept – a key factor for emotional stability throughout life.
The impact of social relationships on physical health is now well documented. People with stable social ties have significantly lower rates of cardiovascular diseases, hypertension, and chronic inflammation. A comprehensive meta-analysis with over 300,000 participants showed that good social integration is associated with over 50% lower overall mortality – an effect comparable to quitting smoking. [6]
Other studies link this effect to reduced cortisol levels, lower systemic inflammation markers (e.g., CRP, IL-6), and improved heart rate variability. Immune function is also strengthened by social support – especially regarding infection susceptibility and recovery processes. [3,8]
In older age, studies also show a clear connection between social activity and cognitive health. Older adults with active social networks have a significantly lower risk of cognitive decline and dementia. [2,7]

Despite the known benefits, many people neglect their friendships – often due to lack of time or work-related stress. But maintaining relationships doesn’t require grand gestures, just intentional, small efforts to keep them alive:
Friendships, as scientifically proven, play a central role in our health. International Friendship Day reminds us not to leave these relationships to chance, but to actively nurture them. Investing time in true connection means investing not only in human closeness but also in long-term physical and mental well-being.