Effects Of Exercise Research Articles

Effects of Exercise on Postprandial Responses to Ad Libitum Feeding in Overweight Men

Previous exercise reduces the lipemic response to meals of fixed size. It is not known whether this triglyceride (TG) attenuation also occurs in response to ad libitum feeding because exercise might induce a compensatory increase in energy intake. It is also unclear whether the effects of a single exercise session on lipemia would be augmented by repeated exercise sessions on consecutive days. Ten sedentary overweight/obese men (aged 35 ± 6 yr) each participated in three 4-d trials in random order: CON (no exercise on days 1-3), EX-1 (exercise session on day 3), and EX-3 (exercise sessions on days 1-3). Each exercise session expended 33.5 kJ·kg−¹ body mass. Subjects consumed an isocaloric diet (provided by experimenters) and avoided alcohol on days 1-3 of all trials. On day 4 of each trial, participants underwent a 7-h metabolic assessment, during which an ad libitum buffet breakfast and lunch was provided, and postprandial plasma and expired air responses were assessed. Day 4 ad libitum energy intake was higher than CON in EX-3 (9216 ± 669 vs 7859 ± 492 kJ, P < 0.05) but not EX-1 (8335 ± 683 kJ). Postprandial TG responses were 27% and 25% lower in EX-1 and EX-3, respectively, than in CON (both P < 0.05), and postprandial insulin responses were 26% (P = 0.06) and 31% (P < 0.05) lower in EX-1 and EX-3, respectively, than in CON. Compared with CON, postprandial fat oxidation was 20% higher in EX-1 and 27% higher in EX-3 (both P < 0.05). Previous exercise attenuates the lipemic response to ad libitum meals, suggesting that exercise's TG-lowering effect will extend into "real-world" settings where food intake is not carefully controlled. This response is not augmented by exercising on repeated days.

Exercise-induced improvement in cognitive performance after traumatic brain injury in rats is dependent on BDNF activation

We have previously shown that voluntary exercise upregulates brain derived neurotrophic factor (BDNF) within the hippocampus and is associated with an enhancement of cognitive recovery after a lateral fluid percussion injury (FPI). In order to determine if BDNF is critical to this effect we used an immunoadhesin chimera (TrkB-IgG) that inactivates free BDNF. This BDNF inhibitor was administered to adult male rats two weeks after they had received a mild fluid percussion injury (FPI) or sham surgery. These animals were then housed with or without access to a running wheel (RW) from post-injury-day (PID) 14 to 20. On PID 21, rats were tested for spatial learning in a Morris Water Maze. Results showed that exercise counteracted the cognitive deficits associated with the injury. However this exercise-induced cognitive improvement was attenuated in the FPI-RW rats that were treated with TrkB-IgG. Molecules important for synaptic plasticity and learning were measured in a separate group of rats that were sacrificed immediately after exercise (PID 21). Western blot analyses showed that exercise increased the mature form of BDNF, synapsin I and cyclic-AMP response-element-binding protein (CREB) in the vehicle treated Sham-RW group. However, only the mature form of BDNF and CREB were increased in the vehicle treated FPI-RW group. Blocking BDNF (pre administration of TrkB-IgG) greatly reduced the molecular effects of exercise in that exercise-induced increases of BDNF, synapsin I and CREB were not observed. These studies provide evidence that BDNF has a major role in exercise's cognitive effects in traumatically injured brain.

Meta‐analysis of the effects of exercise interventions on functional status in older adults

A meta-analysis was conducted to quantify the impact of exercise interventions on the functional status of older adults. Searches of Medline and CINAHL databases revealed 19 randomized controlled trials reporting 30 interventions (n = 2,201). Fixed- and random-effects models were used to estimate overall mean effect sizes (ESs) for functional and physical performance outcomes and activities of daily living (ADL). Modest but statistically significant ESs were found for functional performance and physical performance but not for ADL. Exercise improved functional and physical performance but the improvement may be insufficient to have an impact on ADL. Further studies are needed to determine exercise's effects on ADL and to identify moderators associated with functional status outcomes in older adults.

Correlations Between Eye-Hand Reaction Time and Power of Various Muscles in Badminton Players

In the present study, the relations of simple reaction times of right and left hands with muscle powers of right and left hands, back, and leg were examined. Hand preference was assessed by the modified Edinburgh Handedness Inventory. Measurements for reaction time were taken using the Newtest 2000 Reaction Time Apparatus. Takei Kiki Kogyo Dynamometers were used in measuring the muscle power of the subjects (0–100 kg). The simple reaction time (SRT) for right hand was not correlated with right and left hand and leg. The left hand SRT was significantly negatively correlated with right and left hand and leg powers. The choice RT was significantly correlated with right and left hand powers, but not leg power. There were no right–left differences in simple RT and hand power. These results suggest that sport activities are associated with eye–hand visual reaction time (VRT) and visuospatial intelligence (VSI). Exercise's positive effect may be associated with especially the right brain or left hand.

Swim training prevents hyperglycemia in ZDF rats: mechanisms involved in the partial maintenance of β-cell function

Exercise improves glucose tolerance in obese rodent models and humans; however, effects with respect to mechanisms of beta-cell compensation remain unexplained. We examined exercise's effects during the progression of hyperglycemia in male Zucker diabetic fatty (ZDF) rats until 19 wk of age. At 6 wk old, rats were assigned to 1) basal--euthanized for baseline values; 2) exercise--swam individually for 1 h/day, 5 days/wk; and 3) controls (n = 8-10/group). Exercise (13 wk) resulted in maintenance of fasted hyperinsulinemia and prevented increases in fed and fasted glucose (P < 0.05) compared with sham-exercised and sedentary controls (P < 0.05). Beta-cell function calculations indicate prolonged beta-cell adaptation in exercised animals alone. During an intraperitoneal glucose tolerance test (IPGTT), exercised rats had lower 2-h glucose (P < 0.05) vs. controls. Area-under-the-curve analyses from baseline for IPGTT glucose and insulin indicate improved glucose tolerance with exercise was associated with increased insulin production and/or secretion. Beta-cell mass increased in exercised vs. basal animals; however, mass expansion was absent at 19 wk in controls (P < 0.05). Hypertrophy and replication contributed to expansion of beta-cell mass; exercised animals had increased beta-cell size and bromodeoxyuridine incorporation rates vs. controls (P < 0.05). The relative area of GLUT2 and protein kinase B was significantly elevated in exercised vs. sedentary controls (P < 0.05). Last, we show formation of ubiquitinated protein aggregates, a response to cellular/oxidative stress, occurred in nonexercised 19 wk-old ZDF rats but not in lean, 6 wk-old basal, or exercised rats. In conclusion, improved beta-cell compensation through increased beta-cell function and mass occurs in exercised but not sedentary ZDF rats and may be in part responsible for improved glucoregulation.

Meeting Minutes as a Rhetorical Genre: Discrepancies Between Professional Writing Textbooks and Workplace Practice Tutorial

Unlike experienced collaborators, student teams often attempt to collaborate without effective documentation of meetings. This tendency may be exacerbated by professional writing textbooks, which rarely mention minutes in their chapters on collaboration and provide ineffective examples of meeting minutes that follow a parliamentary style of minutes rather than the action-oriented style that is the norm in most workplace settings. Interviews with three engineering managers are supported by published research in professional communication to show how meeting minutes are essential to projecting a team forward by solidifying consensus and holding individuals accountable for actions. A short exercise designed to teach students how effective minutes function as a management tool is presented along with observational evidence of the exercise's effect on student team practices in both professional writing and computer science team projects

EFFECTS OF AEROBIC AND RESISTANCE TRAINING ON BODY COMPOSITION, RMR, BLOOD LIPIDS, AND MUSCULAR STRENGTH IN MIDDLE-AGED WOMEN AND MEN

The alarming increase in the obesity epidemic raises the essential question of the most effective exercise (EX) and nutrition (N) regimen for optimal body composition and physical health. Limited data exists comparing commonly presrcibed EX and N interventions on indices of overall health. PURPOSE Using two well-known EX and N regimens (American Heart Association, AHA; Body-for-Life, BFL), we provide preliminary data on the relative effectiveness of each for 8wks on body composition (DEXA), RMR, blood lipids, and 1RM of the chest and legs in middle-aged W(42+/−9 yrs) and M (43+/−9 yrs). METHODS Twenty-two W (AHA;n = 10: BFL; n = 12) and 20 M(AHA; n = 10: BFL; n = 10) were weight-matched and assigned into one of two groups. Body composition (DEXA), blood lipids, chest and leg press 1RM, and RMR were obtained on all 42 participants at baseline (day 0) and 8 weeks. RESULTS Significant decreases were observed for % bodyfat (P < 0.05)[(AHA;W, 37+/−7 vs. 35.5 vs. 8%):(AHA;M, 25.8+/−6 vs. 24.8+/−5.5%):(BFL;W, 40.5+/−6.7 vs. 36.6+/−8.3%):(BFL;M,25+/−9.9 vs. 21.6+/−9.6%)], and cholesterol for W and M in BFL and W in AHA (P < 0.05)[(AHA;W, 201.7+/−33 vs. 176+/−16.4mg/dl): (BFL;W, 192.6+/−48.7 vs. 71.4+/−43 mg/dl):(BFL;M, 215+/−19 vs. 71.6+/−30.6 mg/dl)]. Whereas, significant increases (P < 0.001) were observed in chest [(AHA;M, 68+/−11.8 vs. 74.5+/−10kg):(BFL;W, 36+/−7 vs. 44+/−9kg): (BFL;M, 75+/−13.4 vs. 84+/−12.6kg)] and leg 1RM [(AHA;W, 141+/−26 vs. 161+/−35.7kg):(AHA;M, 216+/−23 vs. 248+/−27.7kg):(BFL;W, 158+/−46.6 vs.211+/62.6kg): (BFL;M, 258+/−71.9 vs. 337.5+/−89kg)]. No differences existed for RMR. CONCLUSION The BFL EX and N program elicits similar or greater changes on body composition, total cholesterol and muscular strength than the AHA aerobic EX and N program and should be considered as an effective strategy to combat the obesity epidemic. Supported by EAS, Inc. Golden CO

Aerobic Exercise's Effects on General Well-Being and Anxiety

Aerobic Exercise's Effects on General Well-Being and Anxiety

EFFECT OF EXERCISE DURATION ON PLASMA ENDOTHELIN-1

1316 Endothelin-1 (ET-1) is a potent vasoconstricting peptide released from the vascular endothelium. Isolated exercise sessions of relatively long duration (usually 30 minutes or more) have yielded increases in plasma ET-1 concentrations while shorter exercise sessions (usually graded maximal exercise) have not. The purpose of the present study was to examine the effect of exercise duration on plasma ET-1. Eleven endurance-trained males (age 26±6 yr, VO2max 56±7 mL/kg/min; mean±SD) ran on a treadmill at 70% VO2max on two separate occasions. During a short duration exercise session, subjects expended approximately 800 kcal (60±2 min). During a long duration exercise session, subjects expended approximately 1500 kcal (112±4 min). Order of the sessions was counterbalanced. The short duration session did not produce a change in plasma ET-1 concentration (2.25±0.15 pg/mL before exercise, 2.22±0.15 pg/mL after, mean±SE). However, ten of eleven subjects had increased ET-1 after the long duration session (2.83±0.16 pg/mL before exercise, 3.23±0.15 pg/mL after, p=0.0004). A treatment-by-time effect was present (p=0.003). These results indicate that exercise duration has an effect on plasma ET-1 concentration. Therefore, exercise duration should be considered when investigating exercise's effect on ET-1.

The epidemiology of physical activity and cancer.

Experimental studies in animals and epidemiological studies in human populations support an inverse association between exercise and the development of cancer. Physical activity has been shown to be protective against the development of breast and colon cancer and may also be important for other kinds of cancer such as that of the prostate. The proposed biological mechanisms for the physical activity--cancer association include exercise's effect on immune function, transit time of digestion, hormones, and body fat. There has been little research on physical activity and the effect on progression of cancer, although there are studies to suggest that it may slow the clinical course of the disease. Furthermore, exercise may be beneficial in the treatment of cancer through mood elevation, decreased loss of lean tissue, and increased quality of life. Much is still to be learned about the effect of exercise on cancer. The intensity, duration, frequency, and type of exercise that is relevant need to be clarified. As well, the time period during life when exercise is important has not been determined. It seems reasonable to conclude that exercise, a modifiable risk factor, is beneficial in preventing certain forms of cancer. Public health interventions may hold promise for cancer prevention.

Physical activity as a supplement to a weight-loss dietary regimen

Many effects of exercise are potentially beneficial to weight boss and weight maintenance ( 1 ). A bout of exercise produces an increase in caloric expenditure, the magnitude of the increase being related to the duration, intensity, and type of exercise. Weight-bearing exercise leads to caloric expenditure that is directly related to body weight. Therefore, such activities as walking, jogging, and cross-country skiing would appear to have particular benefits for obese individuals. Muscle-strengthening exercises may produce an added advantage by maintaming or increasing muscle mass. Some have described a carry-over effect ofexercise on metabolic rate (2, 3) but this has been disputed (4). If any long-term effect exists, it probably occurs only after very vigorous and sustained physical activity. Exercise when combined with diet in the treatment of obesity would be expected to bead to greater body fat loss as well as better preservation of lean body mass (LBM) than diet alone. In addition, because resting energy expenditure (REE) is directly rebated to LBM (5), exercise added to a weight-boss regimen would be expected to prevent or lessen a diet-induced decrease in REE. Exercise may also favorably alter substrate and hormone levels associated with the complications of obesity (6), suppress appetite (7), alter substrate oxidation (8), and produce psychological effects of improved general well-being. The conventional wisdom regarding the beneficial aspects ofexercise in conjunction with diet has been chablenged. A recent study in women (9) indicated not only a lack of additional benefit of exercise in weight loss but also a reduction in REE when exercise was combined with diet compared with diet alone. However, a previous study from our laboratories ( 10) indicated clear benefits ofexercise in obese men. LBM was preserved and indices of physical fitness improved. To investigate whether a program of physical activity similar to that used in our previous approach with men would be beneficial in women, we carried out the following study ofthe effects ofexercise in a weight-loss dietary regimen.