Relative maximum oxygen uptake during activities of daily living in very old community-dwelling adults

Introduction
Maximal oxygen uptake (VO2max) decreases with age, may play an important role for activities of daily living (ADL) and
represent a limiting factor for independent living. Regardless, the metabolic cost of common ADL in very old adults is not
well-known. This study aims at evaluating the absolute and relative metabolic cost of selected ADL in very old communitydwelling adults.
Material and methods
Ninety-eight older adults (46% female) were recruited for the ENerGetics in old AGE (ENGAGE) study (80,5 ± 3,8 years,
range 75-90). Participants performed two sets of semi-standardized ADL at their own pace in the laboratory (one light, one
moderate) while oxygen uptake was continuously assessed with the Douglas bag methodology. The light ADL circuit
included getting dressed, combing hair, brushing teeth, setting and cleaning a table, light sweeping, preparing foods, while
the moderate included making the bed, doing laundry, vacuuming, window wash. VO2max was measured with a graded
treadmill walking test by on-line system (Bruce protocol).
Results
VO2max was on average 22,9 ± 5.7 ml O2/kg/min. VO2 for light and moderate ADL circuits was 8,4 ± 1,3 and 10,1 ± 1,6 ml
O2kg/min, respectively, with a relative metabolic cost of 38,8 ± 9,6 % (range: 21-71%) and 46,1 ± 12,3 % (range 23-76%) of
VO2 max. Thirty and 10% of the participants used >50% of their VO2 max. for the moderate/light ADL, respectively.
Conclusions
Several community-dwelling older adults experience relatively high intense metabolic work when performing light and
moderate ADL which ultimately may threaten their independent living.