Life-long outpatient rehabilitation of coronary patients in Slovenia is organized through coronary clubs. The 6-minute walk test (6MWT) is a common outcome measurement used in those clubs to evaluate the cardio-respiratory fitness of patients, as distance walked on the test (6MWD) predicts cardiovascular events in patients with stable coronary heart disease (CHD). The aim of our study was to evaluate the influence of gender, age and weight on the 6MWD in coronary patients.
Testing was performed in 4 clubs in Ljubljana region and 95 patients (33 males and 62 females), age 74.5 ± 7.9, participated in the study. 6MWT was performed according to standardized protocol.
There was no significant difference (F = 0,98; p = 0,755) in 6MWD among males (498 m) and females (492 m). The predicted 6MWD (441 m and 434 m for males and females, respectively) differed significantly (p < 0,001) from measured 6MWD (498 m and 492 m for males and females, respectively). This clearly highlights that physical ability of patients with stable CHD may be underestimated using prediction formulas, hence there is a need for regular annual/biannual testing. Furthermore, as reference values for 6MWD are reported for 5-years intervals we have used same approach in our study, and we have shown that there is a significant difference in 6MWD among different age groups (F = 10,178; p < 0,001), where most prominent differences are rather on a 10-years interval (eg. 60–69y are better than 70–79y). The age of patient explains 41 % (p < 0,001) of the 6MWD in our sample and 6MWD can be calculated as 1041 m – 7.33 x age. Finally, the influence of weight was noticed only through waist to height (WHtR; p = 0,005) ratio rather than among different body mass index grades (p = 0,559). The patients with normal WHtR had statistically bigger 6MWD (521 m) than patients with abnormal WHtR (469 m).
Our results are stressing the importance of regular fitness testing in patients with stable CHD to obtain their actual fitness levels needed to prescribe exercise of proper intensity. Furthermore, there is important influence of age and weight on 6MWD that should also be accounted for in exercise prescription.
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