•  
  •  
 

Abstract

The aging process is associated with a gradual decrease in exercise performance, leg muscle blood flow and oxygenation, and endothelial vascular reactivity. Purpose: To examine potential differences in femoral artery flow-mediated dilation (fa-FMD) and calf muscle oxygenation (HbO2) during low-intensity plantarflexion exercise in older adults. Methods: 43 young-old (YO; n=24, 67 ± 1 years) and older-old (OO: n=19, 70 ± 1 years) individuals were included in this study. We measured body fat % and leg lean mass (LLM) by DEXA and handgrip maximal voluntary contraction (MVC) using a dynamometer. VO2max was estimated using a submaximal treadmill test. fa-FMD was assessed by Doppler ultrasound, measuring the relative change in diameter from baseline to peak hyperemic response following 5 min of muscle ischemia. After a 10-min semi-recumbent rest, participants performed three sets (3-min each) of rhythmic plantar-flexion exercise at increasing intensity (20, 30 and 40 pounds) separated by 1-min of rest. Percent changes (%∆) in muscle HbO2 from baseline to the 3rd min of each set was monitored by near-infrared spectroscopy (NIRS) on the medial gastrocnemius muscle. Results: There were no between-group differences in VO2max, MVC, LLM, body fat %, and fa-BF (P= .07). The OO group had significantly lower fa-FMD compared to the YO group (5.7 ± 1.4 vs 6.7 ± 1.6%, p < .05). During exercise, the OO group exhibited a higher %∆ in HbO2 compared to the YO in sets 2 (-60.0 ± 21.2 vs. -44.7 ± 17.2%, p < .05) and 3 (-66.7 ± 18.8 vs. -52.6 ± 18.2%, p < .05). Conclusion: There was a lower calf muscle oxygenation during low-intensity plantar-flexion exercise performed at the same absolute intensity in OO compared to YO adults. Exercising at a greater relative intensity may explain the lower calf muscle oxygenation in OO adults.

Share

COinS
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.