“Mental practice of the dynamic Qigong technique Wu Qin Xi has the same effect on EEG brain activity as physical training.” In both cases — physical or mental-only practice — theta and alpha waves both increased in beneficial ways.”
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Diana Henz et al. EEG Brain Activity in Dynamic Health Qigong Training: Same Effects for Mental Practice and Physical Training?, Frontiers in Psychology (2017). DOI: 10.3389/fpsyg.2017.00154