Metabolic cost of daily activities and effect of mobility impairment in older adults.

OBJECTIVES

To compare metabolic equivalent (MET) values of common daily tasks in men and women aged 70 and older with normative criteria and to determine the effect of having mobility impairments.

DESIGN

Cross-sectional observational study.

SETTING

University-based research clinic.

PARTICIPANTS

Forty-five participants aged 70 to 90 (mean 76.3 ± 5.1) volunteered to complete 17 daily activities, each lasting 10 minutes.

MEASUREMENTS

Oxygen consumption (VO(2) = mL/kg per minute) was measured through a mask using a portable gas analyzer, and MET values were calculated as measured VO(2) /3.5 mL/kg per minute. Values were compared with normative values and between participants with and without mobility impairments.

RESULTS

Measured METs were different from the established normative criteria in 14 of 17 tasks performed. Normative values underestimated walking leisurely (0.87 ± 0.12 METs) walking briskly (0.87 ± 0.12 METs), and making beds (1.07 ± 0.10 METs) but overestimated gardening (1.46 ± 0.12 METs) and climbing stairs (0.73 ± 0.18). Participants with impairments had significantly lower METs while gardening, vacuuming or sweeping, stair climbing, and walking briskly, although when METs were adjusted for performance speed, the metabolic costs were 16% to 27% higher for those with mobility impairments.

CONCLUSION

Metabolic costs of daily activities are substantially different from normative values in older adults, and having mobility impairments increases this metabolic cost. These results may have implications for practitioners to appropriately prescribe daily physical activities for healthy and mobility-impaired older adults.