Effects of treadmill exercise intensity on spatial working memory and long-term memory in rats

AimsModerate exercise promotes learning and memory. Most studies mainly focused on memory exercise effects of in the ageing and patients. There is lack of quantitative research about effect of regular exercise intensity on different memory types in normal subjects. Present study investigated the effects of different intensities of treadmill exercise on working memory and long-term memory.Main methodsFifty female Wistar rats were trained by T-maze delayed spatial alternation (DSA) task with 3 delays (10 s, 60 s and 300 s). Then they got a 30 min treadmill exercise for 30 days in 4 intensities (control, 0 m/min; lower, 15 m/min; middle, 20 m/min, and higher, 30 m/min). Then animals were tested in DSA, passive avoidance and Morris water maze tasks.Key findings1. Exercise increased the neuronal density of hippocampal subregions (CA1, CA3 and dentate gyrus) vs. naïve/control. 2. In DSA task, all groups have similar baseline, lower intensity improved 10 s delay accuracy vs. baseline/control; middle and higher intensities improved 300 s delay accuracy vs. baseline/control. 3. In water maze learning, all groups successfully found the platform, but middle intensity improved platform field crossing times vs. control in test phase.SignificancePresent results suggested that treadmill exercise can improve long-term spatial memory and working memory; lower intensity benefits to short-term delayed working memory, and middle or higher intensity benefits to long-term delayed working memory. There was an inverted U dose-effect relationship between exercise intensity and memory performance, but exercise -working memory effect was impacted by delay duration.