The relation of exercise training mode, brain oxygenation and cognition in healthy older adults

[摘要] ENGLISH ABSTRACT: Background: Physical exercise has been shown to prevent cognitive decline and dementia inlater life and is generally proposed as a non-pharmacological treatment to reverse or delay theage-related deteriorations in physical and cognitive health. However, it is unknown howdifferent types of exercise will compare with regards to gains in older individuals' physicaland cognitive function and, in particular, the role of high-intensity interval training, has notbeen extended to the cognitive function literature.Aims: The purpose of this thesis was to determine the effects of three different exercisetraining modalities (resistance training, high-intensity interval training and moderatecontinuous training) on physical and cognitive function, as well as cerebral oxygenation.Methods: Sixty seven inactive individuals (55 to 75 years) volunteered for this interventionstudy. Participants were allocated to a resistance training (RT) group (n=22), high-intensityinterval training (HIIT) group (n=13), moderate continuous training (MCT) group (n=13) anda control (CON) group (n=19). Each training group performed three supervised exercisesessions per week over a period of 16 weeks. Cognitive function was assessed every fourweeks with a computerized Stroop task, while physical function was assessed with theTimed-Up-and-Go (TUG) and submaximal Bruce treadmill tests. Changes in cerebraloxygenation during the Stroop task were measured at baseline and after the 16-weekintervention period. Furthermore, muscle strength was assessed in the CON and RT groupswith 10RM leg and bench press tests. The RT and CON groups repeated their baselinemeasurements after a subsequent 16-week detraining (DET) period.Results: Upper and lower body strength generally improved significantly after every fourweeks of RT (with an increase after 16 weeks of 7.3 ± 4.9 kg and 86.6 ± 44.4 kg,respectively; P < 0.001), while TUG performance (-0.2 ± 0.4 s; P < 0.05) and submaximal endurance capacity (0.7 ± 0.9 min; P < 0.001) only improved after 16 weeks. Althoughmuscle strength decreased after detraining, it remained at a level higher than baseline (P <0.05). Submaximal endurance capacity improved after DET (P < 0.001), while TUGperformance returned to baseline. The HIIT group showed a greater improvement in TUGperformance (-0.3 ± 0.4 s; ES = 0.36) and walking endurance (1.4 ± 1.3 min; ES = 0.91)compared to RT and MCT. Within each group only RT showed statistically significantimprovements, with HIIT and MCT presenting the same trend, beyond the 4-weekintervention period, on the measures of executive cognitive function (ES > 0.70). The brainoxygenation results revealed higher relative O2Hb values in CON during the simple andcomplex Stroop tasks at the post-test compared to the pre-test values (P < 0.05), as well ascompared to all three exercise training groups (P < 0.05).Conclusion: Increases in muscular and physical function in older individuals were notinduced in a concurrent manner over the course of a RT programme. Furthermore, olderadults retained a significant amount of muscle strength and submaximal endurance capacityafter a period of DET, while functional mobility was completely reversed. HIIT proved to bemost beneficial for the enhancement of older individuals' aerobic fitness. Exercise trainingproved more beneficial for the enhancement of executive cognitive function compared to notraining. It was also demonstrated that exercise training, independent of the mode, results inmore efficient cerebral oxygenation during cortical activation, whereas HIIT and MCTproved to be superior to RT for task-efficient cerebral oxygenation and improved oxygenutilization during cortical activation in older individuals.

[发布机构] Stellenbosch University