A Comparison of V̇O2, and Muscle and Prefrontal Cortex Tissue Oxygen Extraction between Short and Long-term Aerobically Trained Men Aged 40 - 60 Years

This study was designed to compare systemic O2 utilization (V̇O2), and changes in tissue O2 extraction [deoxyhemoglobin (ΔHHb)] in the vastus lateralis (VL), gastrocnemius (GAST) and pre-frontal cortex (PFC) tissue; between aerobically short-term trained (STT) and long-term trained (LTT) older men (40 - 60 yr) who were matched for current training load. On separate occasions, 14 STT and 14 LTT participants completed ramp incremental (RI) and square-wave constant load (SWCL) tests on a cycle ergometer. In LTT compared to STT; (i) V̇O2 was higher during the RI (p > 0.001) and SWCL (p > 0.001) tests, (ii) ΔHHb in the GAST was greater in SWCL (p = 0.011); and (iii) ΔHHb in the PFC was greater at 90% GET during SWCL (p = 0.011). The additional years of training in LTT compared to STT (LTT 17.50yr ± 6.94yr vs STT 1.68yr ± 0.31yr) were associated with higher V̇O2peak, and sub- GET V̇O2,and ΔHHb in the GAST and PFC at sub- GET exercise, despite there being no difference in current training volume.