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Overview :
Gulati et al evaluated exercise capacity for asymptomatic
women based on age. The ability of a woman to meet age-specific exercise norms
has prognostic significance. The authors are from multiple hospitals in the United States
and Australia.
Exercise capacity was measured on an exercise treadmill.
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Patient Group
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Exercise Capacity
in METS
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all asymptomatic women
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(-0.13 * (age in years)) + 14.7
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active women
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(-0.16 * (age in years)) + 17.9
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sedentary women
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(-0.12 * (age in years)) + 14
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where:
• MET = metabolic equivalent
observed exercise capacity as percent of predicted =
= (actual exercise capacity in METS) / (predicted METS for
age) * 100%
difference between observed and predicted exercise capacity
=
= (observed exercise capacity in METS) - (predicted for age)
Interpretation:
• The risk of
death for a woman with an exercise capacity >= 85% was half that of a woman
with an exercise capacity < 85%.
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Difference in METS
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HR for All Cause Mortality If
Asymptomatic
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HR for All Cause Mortality If Symptomatic
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< 0
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2.6
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3.3
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0 to 3
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1.7
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1.89
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> 3
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1
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1
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where:
• HR = hazard
ratio
• The two types
of risk prediction are quite different. A difference > 3 METS would be seen
in a person who is physically active. The 85% of predicted level at age 55 (6.4
METs) is a difference of -1.2 METs from the predicted (7.6).
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