PurposeThe purpose of this study was to examine the physiological responses resulting from an acute blood flow restriction resistance exercise bout with two different cuff pressures in young, healthy men and women.MethodsThirty adults (18–30 yr) completed a bilateral leg extension blood flow restriction bout consisting of four sets (30–15–15–15 repetitions), with cuffs applied at pressures corresponding to 40% and 60% of the minimum arterial occlusion pressure (AOP) needed to completely collapse the femoral arteries. During each of these conditions (40% and 60% AOP), physiological measures of near-infrared spectroscopy (NIRS) and EMG amplitude (EMG AMP) were collected from the dominant or nondominant vastus lateralis. After each set, ratings of perceived exertion (RPE) were collected, whereas only at baseline and at the end of the bout, mean arterial pressure (MAP) was assessed. Separate mixed-factorial ANOVA models were used to examine mean differences in the change in EMG AMP and NIRS parameters during each set. The absolute RPE and MAP values were also examined with separate ANOVAs. A P value ≤0.05 was considered statistically significant.ResultsRegardless of sex or cuff pressure, the change in EMG AMP was lower in set 1 (14.8%) compared with the remaining sets (22.6%–27.0%). The 40% AOP condition elicited the greatest changes in oxy[heme] and deoxy[heme], while also providing lower RPEs. For MAP, there was an effect for time such that MAP increased from preexercise (87.5 ± 4.3 mm Hg) to postexercise (104.5 ± 4.1 mm Hg).ConclusionsThe major findings suggested that the 40% AOP condition permitted the greatest amount of recovery during the interset rest. In addition, there did not seem to be any meaningful sex-related difference in this sample of young healthy adults.

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According to a study by Timothy A. Salthouse, PhD, at the University of Virginia in Charlottesville, a reduction in cognitive function begins in individuals late 20s. Using cross-sectional, longitudinal, and short-term restest frameworks over a 7-year period, Salthouse and colleagues recruited 2,350 patients from newspaper advertisements, flyers, and referrals from other participants. They ranged between 18-60 years of age and were tested individually. Additional data were acquired from previous studies by Salthouse and colleagues. Many of the participants in Salthouse's study were tested several times during the course of years, allowing researchers to detect subtle declines in cognitive ability. Among the variables analyzed were vocabulary, memory, and reasoning. Measures included the Wechsler Adult Intelligence Scale III. Highest ratings on scales were achieved at 22 years of age, with a reduction in some measures of abstract reasoning, brain speed, and in puzzle solving noticeable at 27 years of age. Average memory declines can be detected at ~37 years of age. Nevertheless, accumulated knowledge skills, such as improvement of vocabulary and general knowledge, actually increase at least until 60 years of age. This implies that cognitive decline is not static across the general population. "These patterns suggest that some types of mental flexibility decrease relatively early in adulthood, but that how much knowledge one has, and the effectiveness of integrating it with one's abilities, may increase throughout all of adulthood if there are no pathological diseases," Dr. Salthouse said. Salthouse and colleagues are continuing research in the same cohort in order to determine whether social relationships, serve to moderate age-related cognitive changes. "By following individuals over time, we gain insight to cognition changes, and may possibly discover ways to alleviate or slow the rate of decline, and by better understanding the processes of cognitive impairment, we may become better at predicting the onset of dementias such as Alzheimer's disease," Dr. Salthouse said.

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