# Age differences in physiological responses to self-paced and incremental $$\dot V O_{2max}$$ testing
Jenkins, L.A., Mauger, Alexis R., Hopker, James G. (2017) Age differences in physiological responses to self-paced and incremental $$\dot V O_{2max}$$ testing. European Journal of Applied Physiology, 117 . pp. 159-170. ISSN 1439-6319. E-ISSN 1439-6327. (doi:10.1007/s00421-016-3508-6) (KAR id:59652)
Purpose: A self-paced maximal exercise protocol has demonstrated higher $$\dot V O_{2max}$$ values when compared against traditional tests. The aim was to compare physiological responses to this self-paced $$\dot V O_{2max}$$ protocol (SPV) in comparison to a traditional ramp $$\dot V O_{2max}$$ (RAMP) protocol in young (18–30 years) and old (50–75 years) participants. Methods: Forty-four participants (22 young; 22 old) completed both protocols in a randomised, counter-balanced, crossover design. The SPV included 5 × 2 min stages, participants were able to self-regulate their power output (PO) by using incremental ‘clamps’ in ratings of perceived exertion. The RAMP consisted of either 15 or 20 W min$$^{−1}$$. Results: Expired gases, cardiac output (Q), stroke volume (SV), muscular deoxyhaemoglobin (deoxyHb) and electromyography (EMG) at the vastus lateralis were recorded throughout. Results demonstrated significantly higher $$\dot V O_{2max}$$ in the SPV (49.68 ± 10.26 ml kg$$^{−1}$$ min$$^{−1}$$) vs. the RAMP (47.70 ± 9.98 ml kg$$^{−1}$$ min$$^{−1}$$) in the young, but not in the old group (>0.05). Q and SV were significantly higher in the SPV vs. the RAMP in the young (<0.05) but not in the old group (>0.05). No differences seen in deoxyHb and EMG for either age groups (>0.05). Peak PO was significantly higher in the SPV vs. the RAMP in both age groups (<0.05). Conclusion: Findings demonstrate that the SPV produces higher $$\dot V O_{2max}$$, peak Q and SV values in the young group. However, older participants achieved similar $$\dot V O_{2max}$$ values in both protocols, mostly likely due to age-related differences in cardiovascular responses to incremental exercise, despite them achieving a higher physiological workload in the SPV.