Role of lifestyle and aging on the longitudinal change in cardiorespiratory fitness.
BACKGROUND
Cardiorespiratory fitness (CRF) in adults decreases with age and is influenced by lifestyle. Low CRF is associated with risk of diseases and the ability of older persons to function independently. We defined the longitudinal rate of CRF decline with aging and the association of aging and lifestyle with CRF.


METHODS
We studied a cohort of 3429 women and 16 889 men, aged 20 to 96 years, from the Aerobics Center Longitudinal Study who completed 2 to 33 health examinations from 1974 to 2006. The lifestyle variables were body mass index, self-reported aerobic exercise, and smoking behavior. Cardiorespiratory fitness was measured by a maximal Balke treadmill exercise test.


RESULTS
Linear mixed models regression analysis stratified by sex showed that the decline in CRF with age was not linear. After 45 years of age, CRF declined at an accelerated rate. For each unit of increase in body mass index, the CRF of women declined 0.20 metabolic equivalents (METs) (95% confidence interval, -0.21 to -0.19); that of men, 0.32 METs (-0.33 to -0.20). Current smokers of both sexes also had lower CRF (-0.29 METs [95% confidence interval, -0.40 to -0.19] for women and -0.41 METS [-0.44 to -0.38] for men). Cardiorespiratory fitness was positively associated with self-reported physical activity.


CONCLUSIONS
Cardiorespiratory fitness in men and women declines at a nonlinear rate that accelerates after 45 years of age. Maintaining a low BMI, being physically active, and not smoking are associated with higher CRF across the adult life span.
Jackson
Andrew S
AS
Department of Health and Human Performance, University of Houston, Houston, TX 77204, USA. udde@mac.com
Sui
Xuemei
X
Hébert
James R
JR
Church
Timothy S
TS
Blair
Steven N
SN
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015992:Body Mass Index; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D008019:Life Style; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010809:Physical Fitness; D012737:Sex Factors; D012907:Smoking