Long-term high-intensity interval training increases serum neurotrophic factors in elderly overweight and obese Chinese adults

Purpose To compare the effects of 12-week high-intensity interval training (HIIT) and vigorous-intensity continuous training (VICT) on cognitive function, physical fitness, VO(2)max, serum neurotransmitters and neurotrophic factors in overweight and obese elderly individuals. Methods Twenty-nine physically inactive older adults (18 males and 11 females) with a mean age of 64.8 +/- 3.9 years were randomly divided into a control group (CON, n = 9), an HIIT group (4 x 3 min at 90% VO(2)max interspersed with 3 min at 60% VO(2)max, n = 10) and a VICT group (25 min at 70% VO(2)max, n = 10) and submitted to 12 weeks of training. Cognitive function questionnaires, physical fitness, VO(2)max, serum neurotransmitters and neurotrophic factors were determined at baseline and post training. Results Twelve weeks of HIIT and VICT improved the VO(2)max (4.19 +/- 2.21 and 1.84 +/- 1.63 mL/kg/min, respectively, p = 0.005), sit-and-reach distance (8.7 +/- 3.0 and 7.8 +/- 3.8 cm, p = 0.033), choice reaction time (- 0.115 +/- 0.15 and - 0.09 +/- 0.15 s, p = 0.004) and one-leg stand time (4.4 +/- 3.4 and 4.2 +/- 4.0 s, p < 0.001) of the elderly participants. The serum concentrations of brain-derived neurotrophic factor (375.5 +/- 247.9 and 227.0 +/- 137.1 pg/ml, p = 0.006), nerve growth factor (33.9 +/- 16.7 and 23.3 +/- 14.5 pg/ml, p = 0.037), neurotrophin-3 (24.2 +/- 9.33 and 16.3 +/- 5.91 pg/ml, p = 0.006) and neurotrophin-4 (10.4 +/- 3.8 and 7.8 +/- 5.0 pg/ml, p = 0.029) increased significantly in the HIIT and VICT groups after training. In addition, compared to VICT, HIIT significantly increased VO(2)max and the serum neurotrophin-3 concentration. Serum concentrations of the neurotransmitters acetylcholine, dopamine and serotonin trended upward with training. No significant change was observed in the cognitive function questionnaire scores (p > 0.05). Conclusion HIIT is suitable for elderly adults and is more effective than VICT for improving VO(2)max and serum neurotrophin-3 concentrations.