Rationale:

The six-minute cycle (6MC) test has been used for many years in North Carolina cardiac rehabilitation (CR) facilities to periodically assess changes in functional performance following both short- and long-term CR participation. Currently, little is known about how long-term CR participation affects changes in 6MC performance over time.

Objective:

This investigation was designed to assess differences in 6MC performance up to 1 year in men and women of North Carolina CR programs as part of an ongoing state outcomes project.

Methods:

For this project, patients aged 40 to 89 years from four multidisciplinary CR programs performed 6MC tests on Schwinn Air-Dyne(TM) cycle ergometers following standardized instructions at CR entry and immediately following 12-, 24-, and 52-weeks (w) of CR participation. Six-minute cycle distance (miles) was compared across time intervals with repeated measures analysis of variance.

Results:

In those who participated for 12 w (N = 2514), 6MC distance increased from CR entry to 12 w (1.15 +/- 0.23 to 1.37 +/- 0.25, P < 0.0001). In those who participated for 24 w (N = 207), 6MC distance increased from CR entry to 12 w (1.1 +/- 0.23 to 1.3 +/- 0.24, P < 0.0001) and again from 12 w to 24 w (1.3 +/- 0.24 to 1.38 +/- 0.27, P < 0.0001). In those who participated for 52 w (N = 105), 6MC distance increased from CR entry to 12 w (1.09 +/- 0.24 to 1.29 +/- 0.23, P < 0.0001) and again from 12 w to 24 w (1.29 +/- 0.23 to 1.35 +/- 0.25, P < 0.0001). In this group, 6MC distance improved from CR entry to 52 w (1.09 +/- 0.24 to 1.37 +/- 0.25, P < 0.0001), but not from 24 w to 52 w (1.35 +/- 0.25 to 1.37 +/- 0.25, P = 0.218) When analyzed separately, men and women demonstrated these same trends, although women did not show the robust improvements in 6MC performance as seen in the men.

Conclusions:

Six-minute cycle performance improves in men and women following 12 w of CR participation and then again after 24 w in the long-term participants. Scores do not improve from 24 w to 52 w in the 1 year participants, but remain significantly higher than entry and 12 w values. Participation in medically supervised CR is recommended for up to 1 year for optimal improvement in physical work performance, as measured by the 6MC test.