A single bout of acute exercise increases oxidative stress and stimulates a transient increase in antioxidant enzymes. We asked whether this response would induce protection from a subsequent oxidative challenge, different from that of exercise, and whether the effects were affected by aging. We compared young (20±1 years, n=8) and older (58±6 years, n=9) healthy men and women. Resistance to oxidative stress was measured by the F 2 -isoprostane response to forearm ischemia/reperfusion (I/R) trial. Each participant underwent the I/R trial twice, in random order; once after performing 45 min of cycling on the preceding day (IRX) and a control trial without any physical activity (IRC). Baseline F 2 -isoprostane levels were significantly lower at IRX compared to IRC (P<0.05) and not different between groups. F 2 -isoprostane response to IRX was significantly lower compared to IRC in young (P<0.05) but not different in the older group. Superoxide dismutase activity in response to acute exercise was significantly higher in young compared to older adults (P<0.05). These data suggest that signal transduction of acute exercise may be impaired with aging. Repeated bouts of transient reactive oxygen species production as seen with regular exercise may be needed to increase resistance to oxidative stress in older individuals.

History: Objectives: Acute exercise can result in post-exercise hypotension (PEH) lasting up to 24-h. Whether exercise performed on consecutive days would lead to an accumulating PEH effect has yet to be determined. The purpose of this study was to compare daily exercise (DE) to exercise performed on alternating days (AE) and control (CON) on PEH. Methods: Sedentary men 18-30 yr with elevated blood pressure (BP) participated in this three-arm randomized cross-over trial. The primary comparison was PEH between three groups (CON, AE, DE) over time (day 1,2,3). Both exercise groups were prescribed the same exercise intensity (70-75%HRmax), and total duration of exercise (90min) on a cycle ergometer. DE performed exercise on three consecutive days (three bouts 30min). AE performed exercise on two alternating days (2 bouts 45min). Following exercise subjects remained in the laboratory for 1-h while BP was taken every 5-min. Results: Nine overweight (BMI=29.2±4.5kg/m 2), young (22.7±2.4years), moderately fit (VO2pe-ak=35.6±7.3 ml.kg.min), male subjects with elevated BP (126.2±10.4 and 73.3±6.4 mmHg) completed the study. There was a significant systolic BP condition by day effect such that on day three systolic BP (CON 119.0±9.3, AE 118.9±15.0, DE 115.0±11.9 mmHg), and diastolic BP (CON 71.9±6.6, AE 68.4±10.3, DE 67.6±6.2 mmHg) were lowest during the post-exercise DE condition (P<0.001). Additionally, DE saw a significant reduction of resting systolic BP between day 1 and day 4 (122.8±10.2 mmHg vs 113.1±12.0 mmHg; P=0.022, respectively) and a borderline significant reduction between day 1 and day 3 (122.8±10.2 mmHg vs 114.8±10.0 mmHg; P=0.051, respectively). DE saw a borderline significant resting diastolic BP reduction between day 1 and day 3 (73.2±7.2 mmHg vs 68.6±6.5 mmHg; P=0.058, respectively) and a significant reduction between day 1 and day 4 (73.2±7.2 mmHg vs 66.4±4.3 mmHg; P=0.022, respectively). Conclusions: In conclusion, the post-exercise BP lowering effect of the prior exercise session appeared to accumulate during DE such that day 3 was the lowest of all conditions and days.

BackgroundWeight cycling (WC) is a widespread behavior associated with elevated laboratory blood pressure (BP). The impact WC may have on ambulatory BP (ABP) is unknown.MethodsImpact of self-reported WC history on ABP was assessed via cross-sectional nonexperimental design. Sixty-five women completed the Weight and Lifestyle Inventory (WALI) questionnaire. The WALI has been shown to be a reliable index of WC (r=0.87, P<0.001). Data were analyzed looking at WC both as a continuous and criterion variable, and subjects were dichotomized as either WC or non-WC (NWC).ResultsWC (n=31) were older (39.7±8.9 vs. 33.1±11.3 years), had a higher percent body fat (47.1%±6.2% vs. 41.4%±7.8%), and were less fit (21.2±5.4 vs. 26.7±7.6 mL/kg/min) than NWC (n=34). No significant correlation between laboratory systolic BP (SBP, P=0.830) or diastolic BP (DBP, P=0.997) and WC was observed. A significant correlation between the number of WC and systolic ABP (r=0.326, P=0.010) and trend for diastolic ABP (r=0.238, P=0.065) was found. SBP (23% vs. 17%, P<0.001) and DBP (13% vs. 9%, P<0.001) load was higher for WC compared to NWC women.ConclusionWC may deleteriously affect BP outcomes that might only be observed when ABP monitoring is used.

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