Effect of aging on treadmill exercise induced theta power in the rat

The effects of aging on the electroencephalogram (EEG) power spectra of 8- and 60-week-old Wistar–Kyoto rats were examined during the waking baseline and treadmill exercise. Using continuous and simultaneous recordings of EEG and electromyogram signals, this study demonstrated that the alpha (10–13 Hz), theta (6–10 Hz), and delta (0.5–4 Hz) powers of the EEG were significantly lower in older rats as compared with young rats during the waking baseline. In the young rats, treadmill exercise resulted promptly in a higher alpha power, higher theta power, and higher theta power percentage as compared with the waking baseline. In the aged rats, treadmill exercise only resulted in a higher theta power and higher theta power percentage. During the treadmill exercise, however, the aged rats still showed a significantly lower exercise-evoked theta power change than the young rats. These results suggested that aging is accompanied by lower EEG activities during waking and this also is accompanied by an attenuated response of the brain to exercise in the rat.     

Influence of Age on Linear and Nonlinear Measures of Autonomic Cardiovascular Modulation

Background: Age has been identified as an independent risk factor for cardiovascular diseases. In addition, autonomic imbalance toward sympathetic preponderance has been shown to facilitate the occurrence of heart disease. Here, we aimed to assess autonomic modulation of cardiovascular parameters during normal ageing applying well‐established linear and novel nonlinear parameters. Methods: Linear and nonlinear measures of heart rate variability and complexity as well as measures of QT interval variability and baroreflex sensitivity were obtained from a total of 131 healthy, medication‐free participants from a continuous age range between 20 and 90 years, who were allocated to three different age groups. Results: Heart rate variability and complexity significantly decreased with age, while regularity of heart rate time series increased. In addition, QT interval variability linearly increased with age, while baroreflex sensitivity showed a pronounced decrease. Overall, concerning effects of ageing, linear and nonlinear parameters showed equal differentiation between groups. Conclusion: These data indicate a shift of autonomic balance toward sympathetic predominance in higher age groups, limiting the reactiveness of the cardiovascular system to adjust to different demands and increasing the risk for developing tachyarrhythmias. Ann Noninvasive Electrocardiol 2010;15(2):165–174     

全科医生札记——布朗医生日记

家庭秘密Nick是我的一位病人,有好几年没看见他了。一个星期五的下午,我们正准备离开去度周末,Nick来到了诊所。他说:“医生,能耽误点儿时间给我看一下病吗?”他看上去十分烦躁不安,我说:“当然,进来吧。”他走进我的办公室,我随手把门关上了,Nick哭了。我只见过女士因为这种或