HEALTH TOPICS 
Infectious health behaviors
A theory about how health and emotions may spread.
People are social by nature, spending about 80% of their waking hours with family, friends, or co-workers. A spate of studies about the health impact of this web of personal relationships — or "social networks," in research parlance — suggests that friends, family members, and even friends-of-friends can "spread" particular health behaviors and emotions, just as they can spread a cold or flu virus.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
New subscriptions to Harvard Health Online are temporarily unavailable. Click the button below to learn about our other subscription offers.