1. Positive Mindset: A study by Harvard Medical School found that a positive and optimistic mindset can reduce the risk of death and prolong average lifespan. Participants were evaluated based on their attitudes and emotions towards life, health, and the future. 

They were then divided into five groups: most optimistic, moderately optimistic, average, moderately pessimistic, and most pessimistic.

Over a 10-year follow-up period, significant events and mortality rates were recorded. 

2. Moderate Exercise:  Another study from Harvard Medical School found that individuals who exceeded this level of exercise lived an average of 4.5 years longer compared to non-exercisers, and those who engaged in even more exercise lived 4.

9 years longer. 

3. Proper Diet: Controlling for factors such as age, gender, health status, and socioeconomic status, individuals who consumed a proper diet lived an average of 3.4 years longer compared to those who did not.