Characteristic of autonomic nerve activation during aerobic interval training in comparison with aerobic endurance training in cardiac rehabilitation

The purpose of this study is to effectiveness in autonomic nerve activation into aerobic interval training (AIT) compared with aerobic endurance training (AET). Seven cardiovascular patients (59.9 ± 12.6 years, 163.6 ± 3.5 cm, 62.2 ± 9.5kg) performed AIT which exercise/pause phase was 60s with 120 s at rest (AITI20) and AET of 10 minutes duration. Exercise intensity was set at the work rate at an anaerobic threshold. Systolic blood pressure (SBP) and heart rate (HR) as an index of sympathetic nerve activation (SNA), high frequency component of frequency distribution in HR (HF), and the heart rate decay for the first 30s (T₃₀) after exercise as an index of parasympathetic nerve activation (PNA) were measured. As a result, AET indicated a tendency of higher increase in SNA, but lower decrease in HF compared with AIT120. Furthermore, T₃₀ in AIT120 indicated a tendency of a rapid compared with AET. However, there was not recognized significant difference between both protocols. We suggested that AIT120 could perform while activation PNA more in comparison with AET. Therefore, AIT120 may be safe for cardiac rehabilitation.