الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The high incidence of age-related diseases has stimulated interest in the scientific search for protective agents that have the capability of preventing premature aging and delaying the onset of aging-associated diseases. Health preservation in old age became a primary goal for medicine, because the increasing longevity in our societies is associated with a rise in morbidity.
Stress is an unavoidable part of life. For older adults, prolonged stress can come from chronic illness, disability, or the loss of a wife or a husband. These types of stressors are long term and can be more difficult to deal with.
One of the most common strategies to deal with stress is to get regular exercise. Exercise releases hormones that help fighting off stress and depression and can improve sense of well-being.
The present work was carried out to demonstrate the effect of stress on serum cortisol,serum glucose and ABP of old aged male rats.The rats included in this study were classified into 4 main groups. Group I (control group) which is fed balanced diet and left undisturbed without exposure to stress or to drug administration but exposed to handling only for 10 days, Group II (stress group) which was subjected to chronic cold stress at 4 °C for 3 hours per day for 10 consecutive days, Group III (Exercise control) which was subjected to swimming exercise training (1 h/day) for 10 consecutive days, and group IV: ˝Stress + exercise group˝ This group was subjected to swimming exercise in addition to cold stress exposure by the same protocols used in previous two groups.
The parameters used to evaluate the effects of stress and exercise in our experimental groups are:
• Serum cortisol.
• Serum glucose.
• Systolic and diastolic blood pressure.
The obtained results of this study could be summarized as follow:
• Studying the effect of chronic cold stress at 4 °C for 3 hours per day for 10 consecutive days resulted in a significant increase in the level of serum cortisol, level of serum glucose and systolic and diastolic blood pressure in group II (stress group)in comparison with group I (control group).
• Studying the effect of swimming exercise training (1 h/day) for 10 consecutive days resulted in a significant rise of serum cortisol and serum glucose level and a non significant reduction in systolic and diastolic blood pressure in group III (exercise control group) in comparison with group I (control group).This reveals that swimming exercise training in our protocol is a sort of stress.
• Comparison of group II (stress group) and group III (exercise control) showed a significant increase in serum cortisol, serum glucose, Systolic BPand Diastolic BP. By this comparison we find out that, although exercise training itself was considered a type of stress, Exercise trained rats have lower BP, serum cortisol and glucose levels than chronic cold stressed rats. This could be explained by difference in the patterns of stress system activation in response to exercise training and chronic cold stress as regard hypothalamic-pituitary-adrenocortical axis (HPA axis), sympathetic nervous system and adrenomedullary hormones.
• Comparison between group II (stress group) and group IV (Stress + exercise group) showed a significant increase in Systolic BP, Diastolic BP and serum glucose level, while there was a non significant increase in serum cortisol. By this comparison we shine out the protective role of exercise training against stress induced rise in blood pressure and serum glucose level. Mechanism of this protection is exercise training induced alteration of autonomic function and modification of some neuroendocrine changes associated with exercise training in chronically stressed rats.
• Comparison between group III (exercise control group) and group IV (Stress + exercise group) showed a significant reduction in Systolic BP, Diastolic BP and serum glucose level, while there was a non significant reduction in serum cortisol.
This comparison was made to shine out the efficiency of our exercise protocol against chronic stress induced elevations in BP, serum cortisol and blood glucose levels. It was effective in reducing BP and blood glucose levels but not against the elevation of serum cortisol.
• Comparison of group IV: (Stress + exercise group) with group I (control group) showed a significant increase in the level of serum cortisol, level of serum glucose and systolic and diastolic blood pressure. By this comparison we show that although exercise training was protective against stress induced rise in blood pressure and blood glucose values of our studied groups these values did not reach the control levels.
from the above results we conclude that exercise training improves stress induced elevation in blood pressure and serum glucose level through exercise induced alteration in autonomic function and modification of some neuroendocrine response to chronic cold stress.