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No description available.

No description available.

To investigate the relationship between pulmonary diffusion limitation, ventilation-perfusion (VA/Q) mismatch, pulmonary transit times (PTT) and pulmonary gas exchange during exercise, 10 highly trained male athletes (age=26.4±4.4 years, Height=185.5±5.3cms, Weight=78.2±8.6 kg, V 02max=5.15±0.521-min-1) under went exercise testing at rest (R) and 150W, 300W and maximal exercise (372±22W), corresponding to an oxygen consumption (V0₂) of 0.41±0.09, 2.16±0.17, 4.32±0.35 and 5.13±0.50 1-min-1respectively, while trace amounts of six inert gases were infused via a peripheral vein. Arterial blood samples, mixed expired gas samples and metabolic data were obtained. Observed alveolar arterial difference ([A-a]D0₂(0)was calculated according to the alveolar gas equation. Indices of VA/Q mismatch: LogSDi and Log SDa and predicted [A-a]D0₂([A-a]DO₂(p)) were derived from 50 compartment model analysis of retentions and excretions of the inert gases. Additional indices of '/A/I,) mismatch: DISPR*, DISPE and DISPR*_E and inert gas alveolar difference ([A-a]D, R(A-a)D and E(A-a)D) were obtained directly from the inert gas data. One to two weeks later, the subjects underwent first pass radionuclide angiography using a Siemens ZLC wide field of view gamma camera. Following in vitro labeling with 99mTechnecium, 5-10 ml of the subject's blood, containing 10-20 mCi of activity, were injected at rest. First pass and post-static data were obtained on an ADAC 3003 computer and cardiac output was calculated using the Stewart Hamilton equation. PTT was determined using deconvolution and centroid methods. Gated radionuclide angiography was then performed at rest, 150, and 300W. On a separate occasion, first pass cardiac outputs and pulmonary transit times were obtained at maximal exercise. Mean arterial partial pressure of 0₂ (Pa0₂) decreased significantly from rest to 150W , and from 150 to 300W to a low value of 86±9 torn, before increasing to near resting values at maximal exercise. [A-a]D0₂(3) increased across each exercise levels however only the increase from 150 to 300 W was significant. The overall and perfusion-related indices of VA/Q mismatch showed a significant increase with exercise, mainly as a result of increasing perfusion of areas of high VA/Q [A-a]D0₂(0 was greater than predicted, becoming significant during heavy exercise, indicating diffusion limitation. Cardiac output increased from 6.9±0.9 1-min-1 (R) to 25.2±2.5 1-min-1 at 300W and 33.3±3.7 1-min-1 at maximal exercise. End diastolic volume increased from R to heavy exercise (p < 0.001), accompanied by a decrease in end systolic volume (p =0.05). Stroke volume and ejection fraction also increased significantly from R to 300W (p <0.001). Deconvolution PTT decreased from 9.32±1.41 s at rest to 2.91±0.30 s during max exercise and was highly correlated with centroid PTT both at rest (r=0.99, p<0.001) and during maximal exercise (r=0.96, p<0.001). PTT during maximal exercise was significantly correlated with Pa0₂ (1=0.65, p<0.05) and [A-a]D0₂(0)_[A-a]D0₂(p) (r=-0.60, p<0.05). Calculated pulmonary blood volume increased during maximal exercise by 57% over resting values to over 25% of total blood volume and when corrected for body surface area correlated significantly with Pa0₂ (r=0.69, p<0.05). There was a significant correlation between (A-a)D, PTT, the ventilatory equivalent for CO₂ and Pa0₂ during maximal exercise (r=0.94, p<0.01) allowing prediction of over 80% of the variance in Pa0₂ between subjects. These data indicate that highly trained athletes develop VA/Q mismatch accompanied by diffusion limitation during maximal exercise. Observed decrease in Pa0₂2 during high intensity exercise is the result of a complex interaction between VA/Q mismatch, hypoventilation and diffusion limitation secondary to shortened pulmonary transit.

The evidence for an increase in resting vagal tone to explain the lower heart rate of endurance athletes remains controversial. This study used spectral analysis of heart rate (HRV) and blood pressure (BPV) variability to examine the vagal and sympathovagal influences on the sinus node in 12 endurance-trained athletes (A) and 10 age and sex-matched control subjects (C) (age: 26(1.2) yrs; VO2max: A: 68.2(2.1) vs C: 41.4(2.0) ml/kg/min; p $<$ 0.05). Continuous ECG and BP recordings were obtained during supine rest, sitting, controlled respiration (12 breaths/min), standing, exercise at heart rates of 100 and 130 beats/min, and after 5 and 15 minutes of seated recovery. No differences were observed between A and C in the vagal or high frequency (HF) components (48.0(4.0) vs 44.2(6.9) nu), in the low frequency (LF) components (55.8(6.9) vs 52.0(4.0) nu), or in the LF/HF ratios (1.72(0.4) vs 1.22(0.2)) of the HRV spectral components at rest or other experimental conditions, despite the lower resting heart rates of the A (53.1(1.8) vs 65.1(2.1) beats/min; p $<$ 0.05). Standing and exercise decreased the HF components and increased the LF/HF ratios similarily in both the A and C, controlled respiration induced similar rises in the HF component of HRV. Despite a significantly higher systolic BP in athletes, no difference was observed between A and C in the HF or LF components of either systolic or diastolic BPV. Exercise induced an increase in the HF component of BPV which was associated with the rise in breathing frequency. These results indicate a similar sinoatrial sympathovagal balance in A and C suggesting that training-induced bradycardia could result from an adaptation in the intrinsic sinoatrial properties. Also, endurance training does not appear to influence the beat-to-beat BPV.

The purpose of this study was to examine the relationship between physical activity (PA) and cognitive function in older adults Additionally, the study sought to determine if older adults adhering to ACSM PA guidelines would exhibit significantly better cognitive function than their less active peers. Thirty-five participants (M= 70.6 ± 4.6 years), 21 males and 14 females free of diagnosed cognitive disorders or prescribed psychotropic medications from the Muncie, IN. region were recruited for analysis. Resting heart rate, blood pressure, health history and basic body composition variables were evaluated to determine study eligibility. The Trail Making Task and Stroop Color and Word Test were used to assess cognitive function. Time spent in sedentary, light and moderate-vigorous PA (MVPA), energy expenditure and total steps were measured for a one-week period by accelerometry (ActiGraph GT3x) and questionnaire (International Physical Activity Questionairre). Weekly MVPA was found to correlate significantly with Stroop Word (W) (r =.446, p = < .05), Stroop Color (C) (r =.389, p = < .05) and Stroop Color-Word (CW) (r =.609, p = < .05) performance outcomes. MVPA was also found to have a significant relationship with Trail Making Test Part B (TMTb) outcomes (r = -.358, p < .05). Energy expenditure was related with cognitive performance where W (r = .416, p = <.05), C (r = .424, p = < .05), CW (r = .656, p = < .05), TMTb (r = -.532, p = < .05) and difference between TMT Parts A and B (TMTdiff) (r = -.485, p = < .05) were significant. Total steps/week were strongly correlated to MVPAACC+ (r = .752, p = < .05) as well as CW scores (r = .388, p < .05). Women were shown to have a stronger relationship between MVPAACC+ and TMTb performance outcomes (r = .732, p < .05). Independent t-tests indicated that older adults participating in > 150 minutes of MVPA weekly perform better on Stroop W, C and CW (p = .003, p = .001, and p = .015, respectively) when compared to less active peers. Increased MVPA indicates improved cognitive performance outcomes in older adults when compared to less active peers. / School of Physical Education, Sport, and Exercise Science

Untrained adult males, aged 25 to 65+ years (N=110) were studied to assess the effects of aging on the exercise responses of middle-aged and older adults engaged in an endurance exercise training program. Subjects were divided into four age group categories and exercised at a training heart rate intensity of 75% Karvoner, for three to six months, until all participants could continuously log two miles. All subjects were involved in pre (T1) and post (T2) testing sessions to assess selected resting and exercising physiological data. A standard two-tailed t-test war, utilized as the method of statistical analysis. Significant increases (p4.05) were demonstrated in V02 max and VE max within all groups. Significant decreases (p4.05) were observed in HR max.. HR rest, body weight, percent body fat, systolic and diastolic blood pressure. It was concluded that exercise can improve various physiological variables studied, but that the effects of age do limit the ability of the older groups to attain the same level of fitness observed in the middle-aged groups.

This study examined and compared the effects of ingesting four different, isocaloric carbohydrate meals (460 kcals), two hour prior to a 60 minute bout of endurance cycling. The meals were chosen to represent a variety of types, forms and modes of delivery of carbohydrate: i) Banana Nut Bread®: semi-liquid, oat based carbohydrate-fat-protein combination, ii) Oatmeal: semi-liquid, oat based carbohydrate, iii) Cream of Wheat®: semiliquid, wheat based carbohydrate, iv) Power BarsTM: dense solid, fructose based carbohydrate-protein-vitamin combination. A standardized exercise and dietary regimen was followed prior to each performance trial. The purpose of the pre-trial preparation was to standardize each subjects endogenous carbohydrate stores thereby placing greater emphasis on the ability of each experimental meal to maintain blood glucose. Dependent variables were assessed at 15 minutes intervals during each performance trial to determine if any of the meals could elicit a different physiological response. No significant differences (treatment x trial) in blood glucose concentration, distance traveled, heart rate, V02, RER or RPE were observed (p > 0.05). It was concluded that none of the experimental meals conferred any particular advantage over the rest and due to this fact, issues such as personal preference, convenience and cost should be considered. / School of Physical Education

The purpose of this study was to determine if previously observed differences in ratings of perceived exertion (RPE) at the same intensities during two graded exercise tests (GXT) were the result of changes in blood lactate concentrations (BLC). Thirteen healthy males (25.3 ±53 yrs.) were maximally tested during two protocols (Bruce and Balke 3.0 mph/2.5 % grade changes every 2 minutes). Subjects were randomly assigned to one GXT and completed the second test after 48 hours; both were completed within one week. Ratings of perceived exertion (RPE) were recorded at the end of each 2 minute stage of the Balke and twice per stage during the Bruce protocol. Blood lactate concentrations (BLC) were collected each minute during both protocols.Results: RPE data was first analyzed using two-way ANOVA (protocol x intensity), and a significant interaction was observed with RPEs being higher at each intensity during the Balke protocol. Mean RPE differences were 1.4, 2.8, and 4.5 for 40, 60, 80% of VO2max respectively. The addition of the BLC at each relative exercise intensity as a covariate in the model suggested that BLC accounted for some of the protocol differences in RPE, at 60 and 80% of VOimax.Conclusion: Differences in RPEs between standard GXT protocols reported in previous studies were due, in part, to differences in BLC. / School of Physical Education

The purpose of this study was to examine the effects of hydration status on the prediction of body composition using BIA, NIR, and DEXA. Twenty healthy males and females ages 18 to 28 were recruited for this study. The subjects were dehydrated in the climate control chamber and engaged in physical exercise, until they lost approximately 1%, 2%, and 3% of their pre-exercise body weight. Percent body fat (%BF), body weight, and urinalysis measures were taken initially on day 1, on day 4 at euhydration, following 1%, 2%, and 3% dehydration, and upon rehydration during day 5. The results indicated that there were significant decreases for %BFBIA and %BFNIR between euhydration and 1%, 2%, and 3% dehydration. %BFDExA did not significantly change.There were also significant differences in the response to dehydration between each technique. Proper hydration should be ensured before %BF is estimated with BIA and NIR. / School of Physical Education