OXYGEN-CONSUMPTION IN ADULT AND AGED C57BL 6J MICE DURING ACUTE TREADMILL EXERCISE OF DIFFERENT INTENSITY/

Submaximal and maximal oxygen consumption was determined in untrained adult and aged male C57BL/6J mice during treadmill running, Each of 12 -month-old (ADULT) and 24-month-old (AGED) male mice was tested on a m otor-driven treadmill once at different speeds. VO2 was measured befor e, during, and after exercise by means of indirect calorimetry in meta bolic treadmill chambers. The resting VO2 averaged 3064.67 +/- 87.71 m L/kg/h for ADULT mice and 2472.95 +/- 69.41 mL/kg/h for AGED mice. Dur ing exercise, VO2 increased linearly with work intensity (running spee d): ADULT mice - from 5908.06 +/- 422.35 mL/kg/h at 3 m/min to 10861.9 9 +/- 174.03 mL/kg/h at 25 m/min; AGED mice - from 5217.25 +/- 263.26 mL/kg/h at 3 m/min to 7817.32 +/- 290.28 mL/kg/h at 20 m/min. Further increase of the running speed resulted in a decline of VO2 in ADULT an d refusal to run in AGED mice. The results of this study demonstrated that in untrained C57BL/6J mice VO(2)max and maximal exercise capacity declined with age. At the same absolute and relative workloads, VO2 w as lower in AGED mice.