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

Abstract

Purpose: To compare the effects of 12-week high-intensity interval training (HIIT) and vigorous-intensity continuous training (VICT) on cognitive function, physical fitness, VO₂max, 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 × 3 min at 90% VO₂max interspersed with 3 min at 60% VO₂max, n = 10) and a VICT group (25 min at 70% VO₂max, n = 10) and submitted to 12 weeks of training. Cognitive function questionnaires, physical fitness, VO₂max, serum neurotransmitters and neurotrophic factors were determined at baseline and post training.

Results: Twelve weeks of HIIT and VICT improved the VO₂max (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 VO₂max 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 VO₂max and serum neurotrophin-3 concentrations.

Chinese clinical trial registry number: No. ChiCTR1900022315, date of registration: 4 April 2019.

Keywords: Aging; Cognition; High-intensity interval training; Neurotrophin-3; VO2max.