https://www.healio.com/psychiatry/journals/psycann/1976-12-6-12/{806b8887-c02e-40c8-a228-57f1cdb2bdba}/the-stress-of-life.pdf

The stress of life

Neural Mechanisms of Extinction Learning and Retrieval

Objectives To examine the effects of aerobic exercise on cognition and other biomarkers associated with Alzheimer disease pathology for older adults with mild cognitive impairment, and assess the role of sex as a predictor of response. Design Six-month, randomized, controlled, clinical trial. Setting Veterans Affairs Puget Sound Health Care System clinical research unit. Participants Thirty-three adults (17 women) with amnestic mild cognitive impairment ranging in age from 55 to 85 years (mean age, 70 years). Intervention Participants were randomized either to a high-intensity aerobic exercise or stretching control group. The aerobic group exercised under the supervision of a fitness trainer at 75% to 85% of heart rate reserve for 45 to 60 min/d, 4 d/wk for 6 months. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50% of their heart rate reserve. Before and after the study, glucometabolic and treadmill tests were performed and fat distribution was assessed using dual-energy x-ray absorptiometry. At baseline, month 3, and month 6, blood was collected for assay and cognitive tests were administered. Main Outcome Measures Performance measures on Symbol-Digit Modalities, Verbal Fluency, Stroop, Trails B, Task Switching, Story Recall, and List Learning. Fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulinlike growth factor-I, and β-amyloids 40 and 42. Results Six months of high-intensity aerobic exercise had sex-specific effects on cognition, glucose metabolism, and hypothalamic-pituitary-adrenal axis and trophic activity despite comparable gains in cardiorespiratory fitness and body fat reduction. For women, aerobic exercise improved performance on multiple tests of executive function, increased glucose disposal during the metabolic clamp, and reduced fasting plasma levels of insulin, cortisol, and brain-derived neurotrophic factor. For men, aerobic exercise increased plasma levels of insulinlike growth factor I and had a favorable effect only on Trails B performance. Conclusions This study provides support, using rigorous controlled methodology, for a potent nonpharmacologic intervention that improves executive control processes for older women at high risk of cognitive decline. Moreover, our results suggest that a sex bias in cognitive response may relate to sex-based differences in glucometabolic and hypothalamic-pituitary-adrenal axis responses to aerobic exercise.

https://jamanetwork.com/journals/jamaneurology/articlepdf/799013/noc90059_71_79.pdf

Effects of aerobic exercise on mild cognitive impairment: a controlled trial.

The effects of predator odors in mammalian prey species: A review of field and laboratory studies

Psychopharmacology: The Fourth Generation of Progress.

The pattern of brain c-fos mRNA induced by a component of fox odor, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), in rats, suggests both systemic and processive stress characteristics.

https://www.d.umn.edu/~rlloyd/MySite/Mind-Body/PTSD/Modulation%20of%20Conditioned%20but%20not%20Unconditioned%20Fear.pdf

Controllable versus uncontrollable stressors bi-directionally modulate conditioned but not innate fear

Predator odors have been shown to elicit stress responses in rats. The present studies assessed the use of domestic ferret odor as a processive stress model. Plasma corticosterone and adrenocorticotropin hormone levels were higher after 30 min of exposure to ferret odor (fur/skin) but not control odors, ferret feces, urine, or anal gland secretions. Behavioral differences were also found between ferret and the control odors as tested in a defensive withdrawal paradigm. In addition, c-fos messenger RNA expression in several brain areas previously associated with processive stress was significantly higher in ferret odor-exposed rat brains than in control odor-exposed brains. These results suggest that ferret odor produces a reliable unconditioned stress response and may be useful as a processive stress model.

/pdf/ferret-odor-as-a-processive-stress-model-in-rats-49s2krsyg0.pdf

Ferret Odor as a Processive Stress Model in Rats: Neurochemical, Behavioral, and Endocrine Evidence

Sex differences in activated corticotropin-releasing factor neurons within stress-related neurocircuitry and hypothalamic-pituitary-adrenocortical axis hormones following restraint in rats.

Regular physical exercise is beneficial for both physical and mental health. By contrast, stress is associated with deleterious effects on health and there is growing evidence that regular physical exercise counteracts some of the effects of stress. However, most previous studies have suggested that prior exercise does not alter the acute hypothalamic pituitary adrenal (HPA) axis responses to stress. The present series of studies provides evidence that in rats, 6 weeks (but not 1 or 3 weeks) of voluntary wheel running reduces the HPA axis responses to lower-intensity stressors such as an i.p. saline injection, exposure to a novel environment or exposure to moderate intensity noise, but not to more intense stressors such as predator odour exposure or restraint. Daily exercise does not appear to be necessary for the reduction in HPA axis responses, with intermittent access (24 h out of each 72-h period) to a running wheel for 6 weeks, resulting in similar decrements in adrenocorticotrophic hormone and corticosterone release in response to 85 dBA noise exposure. Data from in situ hybridisation for c-fos mRNA are consistent with the hypothesis that voluntary exercise results in a decrease in HPA axis responsiveness to a low-intensity stressor at a central level, with no changes in primary sensory processing. Together, these data suggest that 6 weeks of daily or intermittent exercise constrains the HPA axis response to mild, but not more intense stressors, and that this regulation may be mediated at a central level beyond the primary sensory input.

/pdf/hypothalamic-pituitary-adrenal-axis-responses-to-low-4rnx49u93q.pdf

Cher V. Masini

Papers

The pattern of brain c-fos mRNA induced by a component of fox odor, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), in rats, suggests both systemic and processive stress characteristics.

Controllable versus uncontrollable stressors bi-directionally modulate conditioned but not innate fear

Ferret Odor as a Processive Stress Model in Rats: Neurochemical, Behavioral, and Endocrine Evidence

Sex differences in activated corticotropin-releasing factor neurons within stress-related neurocircuitry and hypothalamic-pituitary-adrenocortical axis hormones following restraint in rats.

Hypothalamic Pituitary Adrenal Axis Responses to Low‐Intensity Stressors are Reduced After Voluntary Wheel Running in Rats