FITNESS: THE OVERLOOKED MORTALITY PREDICTOR

1
FITNESS THE OVERLOOKED MORTALITY PREDICTOR IN
THE ELDERLY Brian Emerson, Senior (Exercise
Science) Paul McAuley, PhD, Assistant Professor
ABSTRACT BACKGROUND Cardiorespiratory fitness
(CRF) is a strong predictor of mortality among
the elderly. My aim was to examine the relative
risk (RR) of mortality in healthy, elderly men of
low fitness, relative to those of moderate and
high fitness. METHODS Using the Veterans
Exercise Testing Study (VETS) database, hazard
ratios were calculated for three predetermined
fitness groups (lt5.0, 5.0-9.9, and 10.0 METs)
in a longitudinal study of 981 healthy men aged
at least 65 years referred for exercise
testing. RESULTS During a mean follow-up of 6.9
4.4 years, a total of 208 patients died.
Compared to the low fitness group, men with
moderate and high fitness were 44 and 67 less
likely to die, respectively. Overall, CRF was
protective for mortality each 1-MET increase in
exercise capacity conferred a survival benefit of
12.5. CONCLUSIONS In this cohort of healthy
elderly men, higher fitness was associated with
better survival.

• METHODS
• In the VETS study cohort, 2469 male veterans aged
  65 years and older were referred for exercise
  testing for clinical reasons at the VA Health
  Care Systems in Long Beach and Palo Alto between
  1987 and 2004.
• After excluding patients with an abnormal
  exercise test, documented CVD, or both, the study
  comprised 981 apparently healthy elderly men
  (Table 1).
• All subjects completed a comprehensive physical
  exam and a symptom-limited maximal exercise test.
• Subjects were grouped according to fitness level
  lt5.0, 5.0-9.9, and 10.0 METs.
• Subjects were followed for at least 1 year from
  their baseline examination vital status was
  determined as of December 31, 2004.
• Relative risk (RR) of all-cause mortality was
  assessed by Cox proportional hazards analysis
  adjusted for age, ethnicity, smoking,
  cardiometabolic risk factors and BMI.
• The low-fit group (n 227) was selected as the
  referent group.

Table 2. Multivariate relative risk (95 CI) of
mortality
aAdjusted for age, ethnicity, BMI, smoking, CVD
risk factors, and type 2 diabetes

• KEY FINDINGS
• Elderly healthy men having moderate and high
  fitness saw a reduced mortality of approximately
  one-half and two-thirds, respectively (Figure 1).
• Every 1-MET increase in CRF saw a survival
  benefit of 12.5, irrespective of weight status.
• Fitness was a more powerful predictor of
  mortality than hypercholesterolemia,
  hypertension, obesity, or type 2 diabetes.

Figure 1- Relative risk by CRF category
Table 1. Baseline characteristics by fitness
category
CONCLUSIONS My main finding was that CRF was a
powerful independent predictor of mortality.
While the fact that fitness influences longevity
may not be surprising, its power as a mortality
predictor may be unexpected. Low fitness was
at least as powerful as many other
commonly-acknowledged risk factors for chronic
disease, such as dyslipidemia, hypertension,
obesity, or type-2 diabetes. These data
suggest that fitness should take a more prominent
role in efforts to reduce mortality and they
extend the findings of others as to the clinical
significance of exercise testing and prescription.
Figure 2 Kaplan-Meier survival curves for 981
men (VETS)
REFERENCES Myers J, et al. Fitness versus
physical activity patterns in predicting
mortality in men. Am J Med 2004117912-918. Sui
X, Blair SN, et al. Cardiorespiratory fitness
and adiposity as mortality predictors in older
adults. JAMA 2007 298(21) 2507-2516. Wei M,
Blair SN, et al. Relationship between low
cardiorespiratory fitness and mortality in
normal-weight, overweight, and obese men. JAMA
1999 282(16) 1547-1553.
Abbreviations CRF Cardiorespiratory fitness
METs metabolic equivalents (1 MET 3.5
ml/kg/min oxygen uptake) determined from a
maximal exercise test on a treadmill Values are
means SD, unless otherwise stated