Monitoring high‐intensity interval training in CVD patients: focus on lactate and recovery phases (705.13)

In cardiac therapy, it is relatively unknown if target exercise intensities are being met in the “recovery phases” of interval training (IT). This study describes the metabolic response to interval training in CAD patients using conventional methods and lactate sampling. Thirty‐five stable CAD patients performed step‐wise exercise testing (CPX). Heart rates at 50% ‐ 60% and 80% ‐ 90% of VO2peak (~ 60‐70% and 85‐95% of HRmax) were used to establish IT intensities. Patients performed one bout of supervised IT (4 x 4 minutes high with 3 minute recovery phases). Multi‐vessel CAD patients were on average 70 ± 8 yrs. (71% male). HR and LACmax at CPX and IT were 123 ± 16 bpm and 5.33 ± 1.88 mmol/L and 119 ± 16 bpm and 5.61 mmol/L. Mean IT heart rates were 111 ± 17 bpm for the high intervals (HI) and 91 ± 14 bpm for the recovery intervals (RI), corresponding to 91% and 75% of HRmax as determined from CPX. Target heart rates were met in 74% of HI but only in 27% of RI intervals (see figure). Mean LAC were 4.65 mmol/L and 4.14 mmol/L in high and recovery phases, corresponding to 91% and 80% of LACmax. The LAC steady state threshold (LSST; 4.00 mmol/L) corresponded to 80% of LACmax. To establish and monitor interval training in CAD patients, LAC sampling may assist in accurately meeting target exercise intensities.