Epub ahead of print: Motl et al. Evidence for the different physiological significance of the 6- and 2-minute walk tests in multiple sclerosis. BMC Neurol. 2012 Mar 1;12(1):6.
BACKGROUND: Researchers have recently advocated for the 2-minute walk (2MW) as an alternative for the 6-minute walk (6MW) to assess long distance ambulation in MS'ers. This recommendation has not been based on physiological considerations such as the rate of oxygen consumption (V * O2) over the 6MW range.
The term physiology refers to how the body functions normally.
OBJECTIVE: This study examined the pattern of change in V * O2 over the range of the 6MW in a large sample of MS'ers who varied as a function of disability status.
METHODS: 95 MS'ers underwent a neurological examination for generating an Expanded Disability Status Scale (EDSS) score, and then completion of the 6MW protocol while wearing a portable metabolic unit and an accelerometer.
RESULTS: Oxygen consumption increased significantly every 30 seconds over the first 3 minutes of the 6MW, and then remained stable over the second 3 minutes of the 6MW. This occurred despite no change in cadence across the 6MW (p = .84).
Cadence = speed and rhythm of walking; term often used to describe the movement of a metronome.
CONCLUSIONS: The pattern of change in oxygen consumption indicates that there are different metabolic systems providing energy for ambulation during the 6MW in MS subjects and steady state aerobic metabolism (needing oxygen) is reached during the last 3 minutes of the 6MW. By extension, the first 3 minutes would represent a test of mixed aerobic and anaerobic work (not needing oxygen), whereas the second 3 minutes would represent a test of aerobic work during walking.
"The fact that MS'ers are walking using anaerobic metabolism suggests that they are not very fit or deconditioned. This is not surprising given that you may be disabled and suffer from fatigue. Despite this a graded aerobic exercise programme may help with and improve overall physical functioning and improve mood. Exercise releases endorphins into the brain that elevate your mood and make you feel good."
"How many of you exercise regularly?"