title: Long-term health benefits of physical activity--a systematic review of longitudinal studies.
abstract: BACKGROUND
  The treatment of noncommunicable diseases (NCD), like coronary heart disease or type 2 diabetes mellitus, causes rising costs for the health system. Physical activity is supposed to reduce the risk for these diseases. Results of cross-sectional studies showed that physical activity is associated with better health, and that physical activity could prevent the development of these diseases. The purpose of this review is to summarize existing evidence for the long-term (>5 years) relationship between physical activity and weight gain, obesity, coronary heart disease, type 2 diabetes mellitus, Alzheimer's disease and dementia.
  
  
  METHODS
  Fifteen longitudinal studies with at least 5-year follow up times and a total of 288,724 subjects (>500 participants in each study), aged between 18 and 85 years, were identified using digital databases. Only studies published in English, about healthy adults at baseline, intentional physical activity and the listed NCDs were included.
  
  
  RESULTS
  The results of these studies show that physical activity appears to have a positive long-term influence on all selected diseases.
  
  
  CONCLUSIONS
  This review revealed a paucity of long-term studies on the relationship between physical activity and the incidence of NCD.
authors.affiliation: Institute of Sport and Sport Science, Karlsruhe Institute of Technology, Engler-Bunte Ring 15, 76131 Karlsruhe, Germany. miriam.reiner@kit.edu.
authors.forename: Miriam
authors.initials: M
authors.lastname: Reiner
authors.forename: Christina
authors.initials: C
authors.lastname: Niermann
authors.forename: Darko
authors.initials: D
authors.lastname: Jekauc
authors.forename: Alexander
authors.initials: A
authors.lastname: Woll
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000401:mortality / Q000517:prevention & control; D003704:Dementia / Q000401:mortality / Q000517:prevention & control; D003924:Diabetes Mellitus, Type 2 / Q000401:mortality / Q000517:prevention & control; D005260:Female; D006293:Health Promotion; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009765:Obesity / Q000517:prevention & control; D011322:Primary Prevention / Q000379:methods*; D011379:Prognosis; D011634:Public Health; D016019:Survival Analysis; D013997:Time Factors; D055815:Young Adult