High-intensity exercise training improves perioperative risk stratification in the high-risk patient

Exercise prehabilitation prior to major surgery can improve cardiorespiratory fitness (CRF) and clinical outcome. However, in patients deemed "high--risk" for surgery, the feasibility, optimum training modality and its intensity, duration, and frequency are yet to be defined. We assessed the cardiorespiratory fitness of a 70-year-old female patient requiring major thoraco-abdominal surgery for reconstruction of her esophagus. Cardiopulmonary exercise testing (CPET) on a cycle ergometer was used to determine CRF. A baseline CPET confirmed poor CRF and placed her in a high surgical risk group. This was followed by 16 weeks of unsupervised, home-based, moderate-intensity steady-state (MISS) training followed by 10 weeks of high-intensity interval training (HIIT) under the combined supervision of an exercise physiologist and clinician in hospital. Following MISS training, CPET metrics failed to improve: peak oxygen uptake decreased (14.7-13.7 ml O₂ ·kg^-1 ·min^-1 ; -7%) together with peak power (73-70 W; -4%) and anaerobic threshold (AT) increased (7.8-8.3 ml O₂ ·kg^-1 ·min^-1 ; +6%). However, HIIT resulted in impressive improvement in CRF. Peak oxygen uptake (13.7-18.6 ml O₂ ·kg^-1 ·min^-1 ; +36%), AT (8.3-10.5 ml O₂ ·kg^-1 ·min^-1 ; +27%), peak power (70-102 W; +46%), minute ventilation (35.8-57.7 L·min^-1 ; +61%), and peak heart rate (100-133 b·min^-1 ; +33%) all increased. Ventilatory equivalents for carbon dioxide at AT ( $$ / $$ CO₂ -AT) improved (30-28; -7%). The improvement in CRF resulted in surgical reclassification from high to low risk. In conclusion, preoperative HIIT training can confer a marked improvement in CRF in an elderly surgical patient and is associated with a corresponding reduction in perioperative risk.