Although initial www.selleckchem.com/products/brefeldin-a.html fatigue leads to long-term adaptation without programmed rest and variation to exercise-training volume and intensity, tissue repair may not fully transpire and overtraining syndrome may develop [83]. Moreover, lack of ample recovery for tissue repair may result in chronic inflammation and central fatigue potentially having deleterious effects on exercise performance. Furthermore, a state of chronic inflammation, which impairs immune function, may contribute to an increased probability of obesity, CVD, and diabetes.3.2. Acute and Chronic Inflammation When dissecting the subsequent effects of the inflammatory response, it is necessary to understand that inflammation can be both acute and chronic in nature [84]. Acute inflammation is an immediate response to stress and may not necessarily be indicative of long-term adaptations.

To illustrate, acute stress hormone response, such as cortisol, has increased significantly in response to high-volume resistance training [85]. However, long-term exercise training of two years in length has resulted in decreased resting cortisol concentrations [86]. Thus, chronic exercise training appears to reduce resting cortisol levels. Therefore, acute elevations in markers of stress signify an immediate stress response; however, long-term adaptations to physical activity appear to favor parasympathetic dominance.3.3. Exercise and Acute Inflammation A typical acute response to an infection, stressor, or immune system stimulator lipopolysaccharide (LPS) is the elevation of the proinflammatory cytokine TNF-�� [87].

In rats that were exercised to exhaustion (an average of 102 minutes), an attenuated TNF-�� response was measured compared to the response in nonexercised rats when administered with LPS for up to 6 hours [87]. In agreement, in human data, healthy men who performed aerobic exercise to exhaustion prior to the infusion of LPS exhibited lower levels of TNF-�� compared to a non-exercising group [77]. Likewise, Nosaka and Clarkson [88] reported no increase in plasma levels of TNF-�� following a bout of damaging resistance training of the elbow flexors. Interestingly, TNF-�� levels have been reported to be significantly elevated in obese populations [89, 90]. Indeed, TNF-�� has been established to be associated with insulin resistance, leading to obesity [91].

Ultimately, both aerobic and resistance exercise may be effective in attenuating acute inflammatory responses, which might have significant implications to preventing obesity. 3.4. Exercise and Chronic Inflammation Numerous studies have been conducted on the relationship between exercise and concentrations of CRP [79, 92, 93]. These studies all demonstrate an inverse relationship between CRP concentrations and physical activity [92]. Further, GSK-3 physical fitness measured by maximal oxygen consumption (VO2 max) is also inversely related to CRP concentrations [94].