Effects of high intensity interval training on symptomatology and physical fitness in neurological patients

High-intensity interval training seems beneficial in sports and clinical settings. Sprint interval training at lower training volumes has not yet been frequently applied to clinical populations. This is particularly true for neurological patient. PURPOSE: To present preliminary results on effects of different modes of high-intensity interval training on symptomatology, physical fitness and autonomous function. METHODS: We conduct two independent randomized controlled trials with now 15 patients suffering from migraine (age: 30±9 y; BMI: 21±4 kg/m²) and 10 patients with unipolar depressive disorder (age: 35±9 y; BMI: 25±5 kg/m²). Depressed patients were randomly assigned to either a high-intensity low volume (HILV) program (25×30s at 90% of Pmax) or a continuous aerobic exercise (CAE) regime (20min at 60% Pmax). Migraine patients were either allocated to standard high-intensity interval training at higher volumes (HIIT: 4×4min at 90% of HRmax) or continuous aerobic training (CAT: 45min at 70% of HRmax). We examined symptoms of depression (BDI 2) and headache days, duration and intensity per month as primary outcomes. Submaximal and maximal physical fitness (VO2max, VT), pain thresholds and autonomous function were assessed as secondary outcomes. RESULTS: Depressive symptoms notably decreased in both groups (HILV: ↓45%; Cohen’s d=0.8; CAE: ↓30%; Cohen’s d=1.3). Headache frequency did not change significantly (p=0.45). However , HIIT led to a decrease from 8 to 6 headache days a month (p=0.21, d=0.5). Maximal aerobic capacity did not change in both groups (0.4<p<0.7, 0.2<d<0.4). However, submaximal fitness improved in both groups (Depression (VO2 at VT), pre: 1.2±0.1 vs. post: 1.3±0.1, p=0.04; Migraine, (VO2 at VT), pre: 1.6±0.3 vs. post: 1.8±0.3, p=0.02). Heart rate variability (HRV as SDNN) insignificantly increased (d=0.02) in HILV and decreased (d=0.4) in CAE (HILV, pre: 150±48, post: 161± 84; CAE: pre: 205 ± 85, post: 170± 83). CONCLUSION: HIIT at different training volumes might improve symptomatology and submaximal aerobic fitness. Also HRV seems to benefit from intermittent short-interval training at low volumes in patients with depression. The latter is particular interesting, since depressed patients show reduced HRV. However, more data and studies are further required.