The adoption of regular structured exercise in previously sedentary, middle-aged, and overweight men does not result in a negative compensatory reduction in nonprescribed physical activity. The less-than-predicted weight loss is likely to reflect a compensatory increase in energy intake in response to a perceived state of relative energy insufficiency.

Regular exercise may improve systemic markers of chronic inflammation, but direct evidence and dose-response information is lacking. The objective of this study was to examine the effect and time course of changes in markers of chronic inflammation in response to progressive exercise training (and subsequent detraining). Forty-one sedentary men 45-64 yr of age completed either a progressive 24-wk exercise intervention or control followed by short-term removal of the intervention (2-wk detraining). Serum IL-6 fell by -0.4 pg/ml (SD 0.6) after 12 wk and responded to moderate-intensity exercise. Serum alanine aminotransferase (ALT) activity fell -7 U/l (SD 11) at 24 wk although there was no evidence of any change by week 12 (and therefore ALT required more vigorous-intensity activity and/or a more prolonged intervention). The effect on IL-6 was lost after 2-wk detraining whereas the change in ALT was retained. The temporal fall and rise in IL-6 with training and subsequent detraining in men with high IL-6 at baseline provided a retrospective opportunity to examine parallel genomic changes in peripheral mononuclear cells. A subset of 53 probes was differentially regulated by at least twofold after training with 31 of these changes being lost after detraining (n = 6). IL-6 responded quickly to the carefully monitored exercise intervention (within weeks) and required only moderate-intensity exercise, whereas ALT took longer to change and/or required more vigorous-intensity exercise. Further work is required to determine whether any of the genes that temporally changed in parallel with changes in IL-6 are a cause or consequence of this response.

Markovitch D, Tyrrell RM, Thompson D. Acute moderateintensity exercise in middle-aged men has neither an anti-nor proinflammatory effect.

BackgroundPhysical activity (including exercise) is prescribed for health and there are various recommendations that can be used to gauge physical activity status. The objective of the current study was to determine whether twelve commonly-used physical activity recommendations similarly classified middle-aged men as sufficiently active for general health.Methods and FindingsWe examined the commonality in the classification of physical activity status between twelve variations of physical activity recommendations for general health in ninety men aged 45–64 years. Physical activity was assessed using synchronised accelerometry and heart rate.Using different guidelines but the same raw data, the proportion of men defined as active ranged from to 11% to 98% for individual recommendations (median 73%, IQR 30% to 87%). There was very poor absolute agreement between the recommendations, with an intraclass correlation coefficient (A,1) of 0.24 (95% CI, 0.15 to 0.34). Only 8% of men met all 12 recommendations and would therefore be unanimously classified as active and only one man failed to meet every recommendation and would therefore be unanimously classified as not sufficiently active. The wide variability in physical activity classification was explained by ostensibly subtle differences between the 12 recommendations for thresholds related to activity volume (time or energy), distribution (e.g., number of days of the week), moderate intensity cut-point (e.g., 3 vs. 4 metabolic equivalents or METs), and duration (including bout length).ConclusionsPhysical activity status varies enormously depending on the physical activity recommendation that is applied and even ostensibly small differences have a major impact. Approximately nine out of every ten men in the present study could be variably described as either active or not sufficiently active. Either the effective dose or prescription that underlies each physical activity recommendation is different or each recommendation is seeking the same prescriptive outcome but with variable success.

The aim of the present investigation was to determine whether an acute bout of exercise increases heme oxygenase-1 (HO-1) mRNA accumulation in human lymphocytes. Eight male subjects performed separate exercise and rest trials in a randomised order at least 10 days apart. In the exercise trial subjects ran for 75-min at a speed corresponding to 70% maximal oxygen uptake, and in the resting trial subjects sat calmly in the laboratory for an equivalent period of time. Lymphocytes were harvested from blood samples taken before and after each trial. Total RNA was isolated and used to determine the fold-change in HO-1 mRNA accumulation relative to baseline values using real time reverse transcription-polymerase chain reaction. HO-1 protein was determined by Western blotting. Six of the eight subjects showed an increase in HO-1 mRNA greater than two-fold after exercise. The median peak fold-change was 2.7 fold with one subject showing a particularly pronounced response (20-fold) 24 h post-exercise. In the rest trial the level of HO-1 mRNA did not change over the period of investigation. There was also an increase in HO-1 protein 2 h after exercise. These results complement an earlier study showing that acute exercise of a different type (half marathon) leads to an increase in HO-1 expression in lymphocytes.