- Cardiorespiratory fitness levels tend to decline as we age.  According to the latest issue of Archives of Internal Medicine, the decline in Cardiorespiratory fitness accelerates after age 45.

· Authors of this study write that the US population is aging and is becoming more obese and more sedentary.  The study authors also comment that it has previously been well documented that the cardiorespiratory fitness of men and women declines with age.

· In an attempt to clarify age related changes in physical fitness, researchers studied data on almost 20,000 men and women from 1974 to 2006.  They used a treadmill performance test to determine cardiorespiratory fitness.

· In this study, cardiorespiratory-fitness was expressed as metabolic equivalents (a unit of energy expenditure) and also as a percentage of the peak fitness level at any age.

· In both men and women, the level of fitness was relatively steady until age 45 years.  After that age there was a rapid decline in the level of fitness.

· Cardiorespiratory-fitness is a way of expressing general physical fitness. This study is interesting in that it shows us that physical fitness will decline as we age, especially after age 45.
Declining physical fitness is associated with many forms of chronic disease such as hypertension and diabetes.
Declining physical fitness has also been shown to be associated with higher mortality rates.

· The study results are important and should be a strong encouragement for us to exercise, start an exercise regimen, join a gym or increase what we are currently doing.

Cristopher Geiler, MD
Arch Intern Med. 2009;169:1781-1787.