New Delhi, October 12, 2019 :
The six-minute walk test (6MWT) is the easiest test to assess cardiac fitness. It measures the distance (recorded in meters) a person can walk on a hard, flat surface in 6 minutes. While the test is primarily used to assess exercise tolerance in chronic respiratory disease and heart failure, it may also be used to measure exercise capacity in healthy older adults.
6MWT is an inexpensive, simple to do and easy to administer test, requires no special equipment or specially trained technician/s, well-tolerated and acceptable to patients. These features make it a reliable first-line test to quantify exercise intolerance.
All you need to do is to mark a distance of 50 m on a hard surface and ask the patient to walk this distance for six minutes. The test evaluates the submaximal functional capacity or exercise tolerance as the patient can set his/her own pace of walking during the test and can stop to rest anytime during the test as they traverse back and forth along a marked pathway. The goal is for the individual to walk as far as possible in this duration.
When the 6MWD is reduced, further tests such as pulmonary function test, cardiac function, ankle–arm index, muscle strength, nutritional status, orthopaedic function, and cognitive function may be done to find out the cause
According to ATS guidelines, unstable angina or myocardial infarction during the previous month are absolute contraindications. Stable exertional angina is not an absolute contraindication for a 6MWT, but patients with these symptoms should perform the test after using their anti angina medication and rescue nitrate medication should be readily available.
Interpretation of 6MWT
· Normal: > 500 m (1700 ft); Risk: < 300 m (1020 ft); High risk: < 200 m (680 ft)
· Your cardio fitness needs attention, if you cannot walk 6 minutes at a comfortable pace.
· If the distance walked is less than 200 m, this indicates lower functional capacity and carries a poor prognosis.
· If the walk distance is more than 500 m, the prognosis is good.
· If the walk distance ranges between 200m and 500 m, you can continue to exercise with oxygen supplementation.
· A fall in oxygen saturation (SpO2) of more than 4% during the 6MWT indicates significant desaturation and is a predictor of mortality.