Inoue K, Hanaoka Y, Nishijima T, Okamoto M, Chang H, Saito T, Soya H
Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
Int J Sports Med. 2015 Apr;36(4):280-5. doi: 10.1055/s-0034-1390465. Epub 2014 Nov 27.
Although exercise training improves hippocampus-related cognition, the optimum exercise intensity is still disputed. Based on the lactate threshold (LT, approximately 20 m/min on treadmill) of rats, we have shown that 2 weeks of training with stress-free mild exercise (ME, <LT), but not intense exercise (IE, >LT), comprising exercise stress, promotes adult hippocampal neurogenesis (Okamoto et al., PNAS, 2012), a potential substrate for memory improvement. These results led us to postulate that long-term ME, but not IE, training leads to improved hippocampal function as assessed with a Morris water maze (MWM) task. To test this hypothesis, we investigated the changes in physiological stress levels and MWM task performance in rats assigned to 6 weeks of sedentary control (CONT), ME-training or IE-training conditions. Results showed that, compared to the other conditions, only IE causes general adaptive syndrome (GAS), including adrenal hypertrophy, thymic atrophy and hypercorticosteronemia. In the MWM, ME led to enhanced memory, but not learning, compared with CONT, while IE produced no change in either capacity, probably due to GAS. These findings support the hypothesis that 6 weeks of continuous ME training leads to enhanced hippocampus-related memory, which may have implications for both healthy adults and subjects with low physical capacity.
尽管运动训练可改善与海马体相关的认知功能，但最佳运动强度仍存在争议。基于大鼠的乳酸阈值（LT，在跑步机上约为20米/分钟），我们发现，为期2周的无应激轻度运动（ME，<LT）训练，而非包含运动应激的高强度运动（IE，>LT）训练，可促进成年海马体神经发生（冈本等人，《美国国家科学院院刊》，2012年），这是记忆改善的一个潜在基础。这些结果使我们推测，长期进行ME训练而非IE训练会导致用莫里斯水迷宫（MWM）任务评估的海马体功能得到改善。为验证这一假设，我们研究了分配至6周久坐对照（CONT）、ME训练或IE训练条件下的大鼠生理应激水平和MWM任务表现的变化。结果显示，与其他条件相比，只有IE会引发全身适应性综合征（GAS），包括肾上腺肥大、胸腺萎缩和高皮质酮血症。在MWM实验中，与CONT相比，ME导致记忆增强，但学习能力未增强，而IE在这两种能力上均未产生变化，这可能是由于GAS所致。这些发现支持了以下假设：持续6周的ME训练会导致与海马体相关的记忆增强，这可能对健康成年人和身体能力较低的受试者都有影响。
