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Purpose-The purpose of this study was to examine the relationship of exercise energy expenditure (EEE) with both telomere length and telomerase activity in addition to accounting for hTERT C-1327T promoter genotype.Methods-Sixty-nine (n = 34 males; n = 35 females) participants 50-70 yr were assessed for weekly EEE level using the Yale Physical Activity Survey. Lifetime consistency of EEE was also determined. Subjects were recruited across a large range of EEE levels and separated into quartiles: 0-990, 991-2340, 2341-3540, and 93541 kcalIwk j1 . Relative telomere length and telomerase activity were measured in peripheral blood mononuclear cells (PBMC).Results-The second EEE quartile exhibited significantly longer telomere lengths [1.12 T 0.03 relative units (RU)] than both the first and fourth EEE quartiles (0.94 T 0.03 and 0.96 T 0.03 RU, respectively; P G 0.05) but was not different from the third quartile. Telomerase activity was not different among the EEE quartiles. An association was observed between telomerase enzyme activity and hTERT genotype with the TT genotype (1.0 • 10 j2 T 4.0 • 10 j3 attomoles (amol) per 10,000 cells; n = 19) having significantly greater telomerase enzyme activity than both the CT (1.3 • 10 j3 T 3.2 • 10 j3 ; n = 30) and CC groups (5.0 • 10 j4 T 3.9 • 10 j3 ; n = 20; P = 0.01).Conclusion-These results indicate that moderate physical activity levels may provide a protective effect on PBMC telomere length compared with both low and high EEE levels. Keywords TELOMERE BIOLOGY; EXERCISE ENERGY EXPENDITURE; hTERT GENOTYPE; GENETICS; DNAPhysical activity (PA) and increased physical fitness are known to decrease the likelihood of morbidity and mortality from a variety of causes (e.g., reduced cardiovascular disease (CVD), insulin resistance, and hypertension) (6), with concomitant increases in longevity (21). Whereas the reduction of disease end points will necessarily increase longevity, whether PA also directly affects cellular aging remains unclear for either rodents or humans (7). Telomere length is a primary biomarker of cellular aging that has recently been associated with CVD (1), insulin resistance and hypertension (14), and morbidity and mortality (9). In the present study, we explored the correlation of PA levels with telomere length and telomerase enzyme activity.Address for correspondence: Stephen M. Roth, Ph.D., 2134 SPH Bldg, Department of Kinesiology, University of Maryland, College Park, MD 20742-2611; E-mail: sroth1@umd.edu.. Telomeres are found on the ends of linear chromosomes and act as a mitotic clock (18), which shortens with every cell division until cellular senescence. Thus, telomeres are considered an important aging biomarker (2,4). Telomeres and their length are not, however, static entities but rather are a dynamic system (4). In certain cells, the ribonucleoprotein, telomerase, maintains and lengthens telomeres, allowing continued mitotic activity without progression to senescence (5). In cells with telomerase activity, telomere length can be maintain...

Electroencephalographic (EEG) coherence was assessed during a 4-s aiming period prior to trigger pull in expert marksmen (n = 10) and skilled shooters (n = 9) over the course of a regulation round of small-bore rifle shooting. Although both groups were highly experienced, the skilled group had lower ability. Given that specialization of cortical function occurs as domain-specific expertise increases, experts were predicted to exhibit less cortico-cortical communication, especially between cognitive and motor areas, compared to the skilled group. Coherence was assessed for three frequency bands (low alpha, 8–10 Hz; high alpha, 10–13 Hz; and low beta, 13–22 Hz) using sites F3, Fz, F4, C3, Cz, C4, T3, T4, P3, Pz, P4, O1, and O2. Compared to the skilled group, experts exhibited lower coherence between left temporal (T3) and mid-line frontal (Fz) regions for low-alpha and low-beta frequencies, lower coherence for high-alpha between all left hemisphere sites and (Fz), and lower coherence between T3 and all midline sites for the low-beta band. The results reveal that, compared to lesser skilled shooters, experts engage in less cortico-cortical communication, particularly between left temporal association and motor control regions, which implies decreased involvement of cognition with motor processes.

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In the initial phase of the study (Study 1) electrocortical arousal (EEG alpha activity) was assessed at four standardized sites (T3, T4, 01, and 02) from male and female (N = 17) international-caliber marksmen during rifle shooting performance. The task consisted of the execution of 40 shots at a conventional indoor target from the standing position. During each shot preparation, a significant increase in left temporal and occipital alpha activity was demonstrated, while the right hemispheric activity remained constant. Hemispheric laterality ratios (T4:T3) evidenced a significant shift toward right-brain dominance as the time to trigger pull approached. In the second phase of the study (Study 2) male and female (N = 15) marksmen performed the same shooting task and, additionally, the resultant EEG performance patterns were contrasted to those observed during the mental processing of sterotyped left-brain and right-brain mental tasks. Observed EEG patterns, that is, temporal ratios, during shooting replicated the results of Study 1, and furthermore, indicated that the laterality indices derived during shooting exhibited a more pronounced shift to right-brain processing than did those derived during right-brain mental task performance. The EEG data obtained during the comparative mental task states were used to interpret the shooting performance EEG findings in terms of the implications from bilateral or split-brain cognitive process theory.

Measurements based on the EEG have featured prominently in shaping present-day concepts of the neurocognitive aspects of skilled performance. The techniques include measurements of spectral power, interelectrode coherence, event-related potential components such as the P300, slow potentials, and the method of cognitive inference. The advantages offered by EEG-based approaches lies in their spatiotemporal resolution (potentially 1 mm and less than 1 millisecond, respectively) and the potential to preserve ecological validity, i.e., to obtain measurements of cortical function under the same conditions that the task is normally performed. These studies indicate that activity is reduced in specific regions of the cerebral cortex of experts relative to that observed in novices. These changes occur over time as a result of practice. The authors argue that such cortical change results in less attentional demand and less cognitive interference with motor planning and execution. The findings attest to the plasticity of the central nervous system when one is engaged in goal-directed learning, and hold implications for understanding how the nervous system acquires voluntary skills, whether in the context of the training of an athlete or the rehabilitation of a patient who has lost motor skills due to a disease of the nervous system.

The purpose of this study was to examine whether variability in gaze behavior and cortical activation would differentiate expert (n = 12) and nonexpert (n = 13) small-bore rifle shooters. Spectral-activity and eye-movement data were collected concurrently during the course of a regulation indoor sequence of 40 shots from the standing position. Experts exhibited significantly superior shooting performance, as well as a significantly longer quiet eye period preceding shot execution than did nonexperts. Additionally, expertise interacted with hemispheric activation levels: Experts demonstrated a significant increase in left-hemisphere alpha and beta power, accompanied by a reduction in right-hemisphere alpha and beta power, during the preparatory period just prior to the shot. Nonexperts exhibited similar hemispheric asymmetry, but to a lesser extent than did experts. Findings suggest systematic expertise-related differences in ocular and cortical activity during the preparatory phase leading up to the trigger pull that reflects more optimal organization of the neural structures needed to achieve high-level performance.

Older and younger aerobically trained and sedentary adults participated in an S1-S2-S3 paradigm designed to elicit event-related potential~ERP! and behavioral responses to determine the influence of cardiovascular fitness on cognitive and motor processes. The paradigm provided warning~S1! as to the difficulty level of an upcoming decision task~S2!. Participants had to decide the taller of two bars on presentation of S2 but hold their response until S3, to which they indicated their choice motorically. Results revealed age-related differences for ERP measures as older participants showed increased amplitude of the stimulus preceding negativity~SPN! prior to S2, and longer latencies and equipotentiality of P3 in response to S2. Fitness effects were also observed for the contingent negative variation~CNV! with decreased amplitude for fit relative to sedentary individuals. Age interacted with fitness for P3 latency to S2 as older sedentary individuals showed the longest latency followed by older fit and both younger groups. No significant group differences were observed for reaction time~RT! to S3. Therefore, physical fitness is associated with attenuation of cognitive decline in older individuals and greater economy of motor preparation for both young and older participants.