(October 26, 2009 - Insidermedicine) 

Fitness level declines with age and begins to drop particularly steeply after age 45, according to research published in the latest issue of the Archives of Internal Medicine. Certain lifestyle factors, however, continue to play a role in maintaining fitness.

Here are some tips to help you step up your physical activity level:

•    Take the stairs instead of an elevator or escalator

•    Get off the bus a stop or two from your final destination

•    Park a little further from the store entrance

Researchers from the University of Houston examined the relationship between age, lifestyle factors, and fitness level among nearly 3,500 adult women and 17,000 adult men participating in the Aerobics Center Longitudinal Study. The participants underwent between 2 and 33 health examinations from 1974 to 2006. Their body mass index (BMI) was measured, they indicated how much they engaged in aerobic exercise and whether they smoked, and they underwent an exercise treadmill test.

As expected, fitness level declined with age, but this decline occurred more rapidly after the age of 45. As BMI crept up, fitness level diminished. Smoking also reduced fitness. Being physically active, on the other hand, was associated with maintaining a higher level of fitness.

Today's research demonstrates how fitness declines with age, especially after age 45, but also demonstrates that maintaining a healthy weight, getting regular exercise, and not smoking can help maintain good fitness.