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Biomedical subjects

D C Nieman

Publications and source records attributed to D C Nieman.

At least 91 records · Page 5Linked to original sources
PubMed1993

Exercise training and nutrient intake in elderly women.

This study examined the relationship between moderate exercise training (five 30- to 40-minute sessions per week for 12 weeks at 60% of heart rate reserve) and changes in nutrient intake in a group of 30 sedentary elderly women aged 67 to 85 years. Subjects were placed randomly into two groups (those who walked and those who did calisthenics) and were followed for 12 weeks. Measurements were done at three times (baseline, 5 weeks, and 12 weeks). Dietary intake was based on 7-day food records. The 12-week walking program resulted in a significant (12.6%) improvement in maximum oxygen consumption (VO2max) but no change in body weight or skinfold thicknesses compared with the calisthenics program. Despite the improvement in cardiorespiratory fitness, no significant group x time interaction effects were observed for most of the nutrient intake variables tested. To test the effects of high levels of physical activity on nutrient intake, cross-sectional comparisons were made at baseline between highly conditioned and sedentary elderly women. The highly conditioned elderly women had higher energy and nutrient intakes, especially when expressed on a weight-adjusted basis. However, no differences in measures of dietary quality were found. Dietitians should not expect spontaneous improvement in either the quantity or quality of nutrient intake by elderly women who adopt a moderate exercise program. Although nutrient intake was greater in highly conditioned elderly women, their level of fitness and physical activity may be beyond the reach of many elderly women.

Aged↗
PubMed1993

Cardiorespiratory responses to exercise training in septuagenarian women.

Cardiorespiratory responses to a 12wk moderate exercise training program were examined in 30 sedentary elderly women (mean age = 73.6 +/- 0.7 yr). In addition, 12 highly conditioned (HC) older women (mean age = 72.5 +/- 1.8 yr; 11.2 +/- 1.2 yr training; 1.6 +/- 0.2 hr.d-1 aerobic activity) were tested at baseline for cross-sectional comparisons. The VO2max and VEmax of the HC subjects were 67% and 36% higher, respectively, (p < 0.001) than the combined sedentary subjects at baseline. Sedentary subjects were randomly assigned to a walking (WALK) or calisthenics control (CAL) group. The WALK group exercised 5 d.wk-1 for 30-40 min per session at 60.0 +/- 1.9% heart rate reserve while the CAL group engaged in mild musculoskeletal exercise. The WALK group demonstrated significant improvement in VO2max compared to CAL subjects at 12 wk (12.6% vs 2.2%, F = 5.74, p = 0.005). These data show that septuagenarian women demonstrate significant improvement in maximal cardiorespiratory fitness through moderate exercise training.

Aged↗
PubMed1993

Physical activity and serum lipids and lipoproteins in elderly women.

OBJECTIVE: The relationship between cardiorespiratory exercise and serum lipid and lipoprotein levels was studied in elderly women. DESIGN: Randomized controlled experimental design with a follow up of 12 weeks; cross-sectional comparison at baseline. SETTING: Community-living elders in university exercise facilities. PARTICIPANTS: Thirty-two apparently healthy, sedentary elderly Caucasian women, 67 to 85 years of age. Ten highly conditioned elderly women, 65 to 84 years of age, who were active in endurance competitions and had been training for 11.2 +/- 1.2 years, were recruited at baseline for cross-sectional comparisons. INTERVENTIONS: Sedentary subjects were randomized to either a walking or calisthenic group. Intervention groups exercised 30 to 40 minutes, 5 days a week for 12 weeks, with the walking group training at 60% heart rate reserve and the calisthenic group engaging in mild range-of-motion and flexibility movements that kept their heart rates close to resting levels. MEASUREMENTS: Serum lipids and lipoproteins, maximal aerobic capacity (VO2 max), four skinfolds, and dietary intake at baseline and after 5 and 12 weeks. RESULTS: When the highly conditioned group and combined group of sedentary subjects were compared at baseline, serum high-density lipoprotein cholesterol (HDL-C; 1.61 +/- 0.14 vs 1.27 +/- 0.05 mmol/L, respectively; P = 0.048) and triglycerides (1.29 +/- 0.15 vs 2.00 +/- 0.15, respectively; P = 0.002), but not total serum cholesterol (5.72 +/- 0.36 vs 5.72 +/- 0.19 mmol/L, respectively) and low-density lipoprotein cholesterol (LDL-C; 3.62 +/- 0.36 vs 3.72 +/- 0.18 mmol/L, respectively), were significantly different. Twelve weeks of moderate cardiorespiratory exercise improved the VO2max of the sedentary subjects 12.6% but did not result in any change in body weight, energy intake, dietary quality, or any of the serum lipids or lipoproteins. CONCLUSION: Highly conditioned and lean elderly women, when compared with their sedentary counterparts, had higher HDL-C and lower triglycerides, but similar total serum cholesterol and LDL-C values. However, twelve weeks of moderate cardiorespiratory exercise were not associated with an improvement in serum lipid or lipoprotein profiles in previously sedentary elderly women.

Aged↗
PubMed1993

Physical activity and immune function in elderly women.

The relationship between cardiorespiratory exercise, immune function, and upper respiratory tract infection (URTI) was studied in elderly women utilizing a randomized controlled experimental design with a follow-up of 12 wk. Thirty-two sedentary, elderly Caucasian women, 67-85 yr of age, who met specific selection criteria, were randomized to either a walking or calisthenic group; 30 completed the study. Twelve highly conditioned elderly women, 65-84 yr of age, who were active in endurance competitions, were recruited at baseline for cross-sectional comparisons. Intervention groups exercised 30-40 min, 5 d.wk-1, for 12 wk, with the walking group training at 60% heart rate reserve and the calisthenic group engaging in mild range-of-motion and flexibility movements that kept their heart rates close to resting levels. At baseline, the highly conditioned subjects exhibited superior NK (119 +/- 13 vs 77 +/- 8 lytic units, P < 0.01) and T (33.3 +/- 4.9 vs 21.4 +/- 2.1 cpm x 10(-3) using PHA, P < 0.05) cell function, despite no differences in circulating levels of lymphocyte subpopulations. Twelve weeks of moderate cardiorespiratory exercise improved the VO2max of the sedentary subjects 12.6%, but did not result in any improvement in NK cell activity or T cell function. Incidence of URTI was lowest in the highly conditioned group and highest in the calisthenic control group during the 12-wk study, with the walkers in an intermediate position (chi-square = 6.36, P = 0.042). In conclusion, the highly conditioned elderly women in this study had superior NK and T cell function when compared with their sedentary counterparts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Selected scientific aspects of marathon racing. An update on fluid replacement, immune function, psychological factors and the gender difference.

Four topics are addressed: fluid/fuel replacement during the marathon, marathoning and susceptibility to infection, psychological aspects of elite marathoners and the gender gap in marathon performance. Although these topics are diverse, they all relate to practical questions raised by coaches and athletes. Evidence from laboratory and field studies indicates that it is advisable for marathoners to consume 800 to 1000 L/h of sports drink providing 45 to 60 g/h of carbohydrate. It is strongly suggested to practice fluid consumption during training sessions as it is probable that tolerance to drinking during running is a trainable adaptation. Epidemiological and clinical research support the concept that marathon training and racing increase the runner's risk of upper respiratory tract infections because of negative changes in immune function. Susceptibility to infection may be reduced by proper nutrition, adequate sleep, appropriate recovery between vigorous workouts and minimal exposure to sick people during periods of heavy training and major races. Although psychological research in this area is still limited, evidence suggests that elite marathoners rely primarily on associative strategies during competition while judiciously dissociating in order to cope with pain. It is recommended that coaches and athletes interested in employing psychological interventions seek assistance from professionals well trained in the fields of both psychology and exercise science. Will women soon outrun men? Over the past 2 decades societal views and training practices of women distance runners have changed greatly, yet certain performance-related biological differences between men and women are unlikely to change.

Disease Susceptibility↗
PubMed1993

Relationship between body image and percent body fat among college male varsity athletes and nonathletes.

Three groups of students from a large midwestern university (15 varsity swimmers, 15 varsity football players, and 15 nonathletes) were administered a 20-item questionnaire concerned with body image and subsequently underwent skinfold measurements to assess percent body fat. Scores obtained were correlated to estimate the relationship between body image and adiposity. For the groups combined (N = 45) the relationship was significant and inverse (r = -0.51). For the nonathletic group a significant value -0.76 was found; for the two groups of athletes there was no relationship (rs = 0.002 and -0.059 for football players and swimmers, respectively). We conclude that body image as measured in this study in inversely related to percent body fat among college men, especially among students not engaged in varsity sports.

Adipose Tissue↗
PubMed1993

Effects of high- vs moderate-intensity exercise on natural killer cell activity.

The effect of 45 min of high- (80% VO2max) vs moderate- (50% VO2max) intensity treadmill exercise on natural killer cell cytotoxic activity (NKCA) was investigated in 10 well-conditioned (66.0 +/- 1.9 ml.kg-1.min-1), young males (22.1 +/- 1.3 yr). Blood samples were taken before and immediately after exercise, with three more samples taken during 3.5 h of recovery, and analyzed for proportion of NK cells (CD3-CD16+CD56+) and NKCA. Exercise at 80% vs 50% VO2max resulted in a greater immediate postexercise increase in proportion of NK cells, followed by a 1-h and 2-h decrease below preexercise levels for both intensity conditions. NKCA rose significantly above preexercise levels following high- but not moderate-intensity exercise. For both exercise intensity conditions, NKCA tended to drop below preexercise levels by 1 h postexercise, rising back to preexercise levels by 3.5 h postexercise. When NKCA was expressed on a per-NK cell basis, however, no change relative to preexercise levels occurred following moderate-intensity exercise, while a significant increase occurred after 2-h recovery from high-intensity exercise. These data demonstrate that both high- and moderate-intensity exercise are associated with significant shifts in circulating proportions of NK cells which significantly influence interpretation of NKCA data based on assays using separated mononuclear cells.

Adolescent↗
PubMed1993

The effects of a walking program on body composition and serum lipids and lipoproteins in overweight women.

Few prospective studies have been conducted with women to examine the effects of walking on body composition and serum lipid profiles. Overweight women were randomly assigned to either an exercise EX (no. 18) or a nonexercise NEX (no. 18) group. The EX group participated in five 45 min sessions/week of brisk walking at 62 +/- 2% VO2max for 15 weeks. Statistical analysis (2 x 3 repeated measures ANOVA) revealed that the pattern of change in total body weight [F(2.68) = 6.65, p = 0.002] but not body fat percentage, was significantly different between EX and NEX groups; NEX subjects had a 1.6 +/- 0.5 kg gain in contrast to no change in EX subjects. The pattern of change in serum triglycerides, total cholesterol, and LDL-C was not significantly different between groups. The interaction statistic for HDL-C, however, was significant [Pillais Trace (2.33) = 3.73, p = 0.035] with HDL-C tending to rise in the NEX group in contrast to a small decrease in the EX group. Change in kilocalorie intake was positively correlated with change in HDL-C, total cholesterol, and body weight. Change in body weight also correlated positively with change in HDL-C. Our findings suggest that moderate exercise training alone may not be a sufficient stimulus to affect body composition and serum lipid profiles favorably in overweight women.

Adult↗
PubMed1992

Effects of brief, heavy exertion on circulating lymphocyte subpopulations and proliferative response.

Ten healthy males (mean age 22.3 +/- 0.8 yr) pedaled with maximal effort for 30 s against a workload adjusted prior to the start of the test to 0.98 N.kg body mass-1. Blood samples were collected before, and 3 min and 1 h following exercise. Peak and average power mean values were 1020 +/- 51 and 738 +/- 34 W, respectively. Total leukocytes increased 40% in response to the exercise bout, but were 16% below pretest levels after 1 h of recovery (F = 123, P < 0.001). Neutrophils and lymphocytes represented approximately 60% and 30% of the leukocytosis, respectively. Lymphocytes increased 30% following exercise, but were 36% below pretest levels after 1 h recovery (F = 56.4, P < 0.001). The post-test lymphocytosis can be explained primarily from the 176% increase in natural killer cells (NK) and 28% increase in cytotoxic/suppressor T cells, while the 1-h recovery lymphopenia occurred because of a sharp decrease in total T cells and a moderate decrease in NK cells. No significant changes in lymphocyte proliferative response or serum immunoglobulin levels were found when appropriate adjustments for changes in plasma volume or lymphocyte subset changes were made. Plasma epinephrine increased 300% in response to the exercise bout, and best explains the measured changes in circulating levels of lymphocyte subsets. These results demonstrate that changes in circulating levels of leukocyte and lymphocyte subsets, especially NK cells, occur rapidly in response to 30 s of brief, heavy exertion.

Adult↗
PubMed1992

Comparison of six microcomputer dietary analysis systems with the USDA Nutrient Data Base for Standard Reference.

We compared the general operating features and nutrient databases of six microcomputer dietary analysis systems. A 3-day food record with 73 food items was entered into each program; nutrient averages were compared with the US Department of Agriculture Nutrient Data Base for Standard Reference (USDA NDB), full version, release 9, for microcomputers. The six programs were found to vary widely in cost, number of foods and nutrients in the database, use of non-USDA data and imputation of data for missing values, number of print/export options, time to analyze the 3-day food record, and overall ease of use. Although all of the microcomputer dietary analysis systems were within 7% of the USDA NDB for energy, protein, total fat, and total carbohydrates, the proportion of other nutrients varying more than 15% from the USDA NDB varied considerably between programs. Variance among programs for 3-day food record nutrient values occurred because of differences in the number of food items included in the database (leading to varying degrees of substitution), the recency of the nutrient data (whether or not the most recent USDA releases had been incorporated), and the number of missing values (the degree to which non-USDA sources or estimated calculations were used to fill in the blanks from the USDA standard). Our results demonstrate that it is important for each dietitian to carefully choose a microcomputer dietary analysis system that is suitable to specific and predetermined needs.

Databases, Factual↗
PubMed1991

The effects of moderate exercise training on psychological well-being and mood state in women.

The relationship between moderate exercise training (five 45 min sessions/week, brisk walking at 62 beta +/- 2% VO2max for 15 weeks, psychological well-being and mood state was investigated in a group of 35 sedentary, mildly obese women. A 2 (exercise (EX) (N = 18), and nonexercise (NEX) (N = 17) groups) x 3 (baseline, 6-week, 15-week testing sessions) factorial design was used with data analyzed using repeated measures ANOVA. Four psychological tests were administered: Daily Hassles Scale (DHS), General Well-being Schedule (GWB), Spielberger State Anxiety Inventory (S-Anxiety), and Profile of Mood States (POMS). The EX and NEX groups had significantly different patterns of change over time for GWB total scores [F(2,66) = 5.72, p = 0.005] and the GWB subscales 'energy level' and 'freedom from health concern or worry'. Scores for the EX group were elevated at both 6 and 15 weeks. General well-being total scores and subscale 'energy level' scores were significantly correlated with improvement in submaximal cardiorespiratory fitness (r = -0.41, p = 0.014; r = -0.40, p = 0.017, respectively). Exercise training also had a significant effect on frequency but not intensity of DHS scores, and S-Anxiety, with a significant decrease seen in the EX group at 6 weeks but not 15 weeks. Profile of Mood States scores were not significantly related to exercise training. These data support the results of other studies that have reported improvement in general psychological well-being with exercise training.

Adaptation, Psychological↗
PubMed1991

The effects of acute moderate exercise on lymphocyte function and serum immunoglobulin levels.

The extent and duration of changes on lymphocyte function and serum immunoglobulin (Ig) levels were examined in 12 women who walked 45 min at 60% VO2 max in a laboratory setting. A 2-factor, 2 x 6 design with repeated measures on both factors was utilized. The first factor was condition (exercise and rest), and the second factor was time (six times of measurement over a 24-h period), with treatment order counterbalanced. The 45-min walk, in comparison to rest in a seated position, was not associated with significant changes in circulating numbers of interleukin-2-activated T cells (CD5 and CD25) or on spontaneous or concanavalin-A-stimulated lymphocyte proliferation. A trend for decreased phytohemagglutinin-stimulated lymphocyte proliferation in comparison to the rest condition, however, was seen 1.5 h following the exercise bout (p = 0.047). The patterns of change for serum IgG, IgA, and IgM were significantly different (p = 0.001, p less than 0.001, p = 0.010, respectively) between conditions. IgG rose 7.2% immediately following exercise, and then returned to baseline 1.5 h later, which contrasted significantly with changes in the rest condition. These same patterns of change occurred also with IgA and IgM, but increases immediately following exercise were not significant, although a trend was seen for IgA (p = 0.03). The 45-min walk had no effect on plasma cortisol and epinephrine levels relative to the rest condition, but was associated with a significant 89% increase in norepinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The effects of acute and chronic exercise of immunoglobulins.

The effects of acute exercise (both graded-maximal and submaximal) and exercise training on resting immunoglobulin levels and immunoglobulin production are reviewed. Brief graded-maximal or intensive short term submaximal exercise tends to be associated with increases in serum immunoglobulins, the pattern of which does not vary between athletes and nonathletes. Plasma volume changes appear to largely explain these acute increases. Acute moderate exercise, such as a 45-minute bout of walking, on the other hand, has been associated with a transient rise in serum immunoglobulin levels despite no change in plasma volume. This increase is probably the result of contributions from extravascular protein pools and an increased lymph flow. Total serum immunoglobulin changes following less than 40 km of running are minor and/or statistically insignificant, although the concentration of IgG is observed to be at its lowest by 1.5 hours after exercise. The greatest effect of acute submaximal exercise appears to be on serum IgM levels which tend to increase, although results are somewhat inconsistent. Various mechanisms of stimulation have been proposed to explain the exercise-induced effect on IgM, which is the first antibody class produced in an immune response. These mechanisms include nonspecific noradrenergic sympathetic neural interactions with the immune system and the possibility of antigen stimulation through greater-than-normal quantities of microorganisms entering the body through both increased ventilation rates and breakdown of natural mucosal immunity by drying of airway secretions. When athletes run 45 to 75 km at high intensities, serum immunoglobulin levels have been reported to be depressed for up to 2 days. Thus intense ultramarathon running may lead to greater and longer lasting decreases in serum immunoglobulin levels than following exercise of shorter duration. IgA and IgG, immunoglobulins commonly found in airway and alveolar space secretions, may have diffused from the serum during recovery from prolonged endurance exercise nonspecifically and/or in response to microbial agents and antigens introduced into the airways during the exercise bout. It has been well established that prolonged endurance exercise is associated with muscle cell damage and local inflammation. It has been hypothesised that natural (IgM) autoantibodies may be used to assist macrophages in disposal of muscle cell breakdown products. This could occur either by IgM binding to breakdown products present in the blood, followed by their clearance from the circulation, or it is possible that these antibodies may leave the circulation to carry out this same function in tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Exercise↗
PubMed1991

The effects of moderate exercise training on immune response.

The relationship between moderate exercise training (ET) (five 45-min sessions per week, brisk walking at 60 heart rate reserve for 15 wk) and changes in immune system variables and function was investigated in a group of 36 sedentary, mildly obese women. The study was conducted using a two (exercise (EX) and nonexercise (NEX) groups) by three (baseline, 6 wk, and 15 wk testing sessions) factorial design, with data analyzed using repeated measures ANOVA. The pattern of change over time between groups for number of peripheral blood lymphocytes (total), T cells (CD5), B cells (CD20), and serum IgG, IgA, and IgM levels was significantly different. This was not the case for spontaneous blastogenesis or number of T helper/inducer cells (CD4) or T cytotoxic/suppressor cells (CD8). Within-EX-group changes were characterized by significant decreases in percentage and number of total lymphocytes, and in T cell number after 6 wk, and significant increases in each of the serum immunoglobulins after both 6 and 15 wk of training. B cell number increased significantly in NEX subjects relative to baseline values at both 6 and 15 wk, with no significant changes experienced in EX subjects. In summary, these data suggest that moderate ET is not associated with an improvement in lymphocyte function but is associated with a 20% increase in serum immunoglobulins and several small changes in circulating numbers of immune system variables, highlighted by significant decreases in circulating numbers of lymphocytes, particularly the T cell subpopulation. These changes were especially apparent after 6 wk of training, with some attenuation by 15 wk.

Adult↗
PubMed1991

The effects of acute moderate exercise on leukocyte and lymphocyte subpopulations.

The extent and duration of changes in circulating leukocyte and lymphocyte subpopulations, cortisol, and catecholamines were examined in 12 women who walked 45 min at 60% VO2max in a laboratory setting. A two-factor, 2 x 6 design with repeated measures on both factors was utilized. The first factor was condition (exercise and rest), and the second factor was time (six points of measurement over a 24-h period), with treatment order counterbalanced. The 45-min walk, in comparison with rest in a seated position, was associated with a significant but moderate leukocytosis and lymphocytosis immediately following the walk. The leukocytosis was still evident after 3 h of recovery and was primarily due to a neutrophilia. The change in lymphocyte count, relative to baseline levels and the control condition, lasted less than 1.5 h, with an increase in the natural killer (CD16 and/or CD56) and cytotoxic T cell component (CD3 and CD16 and/or CD56) (NKCT) representing approximately two-thirds of the lymphocytosis and T cells (CD5) the other third. A significant decrease in the CD4:CD8 ratio was seen, with cytotoxic/suppressor (CD8) cells increasing and helper/inducer (CD4) cells demonstrating little change in comparison with baseline. This seems to have been due to a subpopulation of CD8 (low density antigen) cells, probably natural killer cells. The 45-min walk had no effect on plasma cortisol and epinephrine levels relative to the rest condition but was associated with a moderate increase in norepinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The effects of moderate exercise training on natural killer cells and acute upper respiratory tract infections.

A randomly controlled 15-wk exercise training (ET) study (five 45-min sessions/wk, brisk walking at 60% heart rate reserve) with a group of 36 mildly obese, sedentary women was conducted to investigate the relationship between improvement in cardiorespiratory fitness, changes in natural killer (NK) cell number and activity, and acute upper respiratory tract infection (URI) symptomatology. The study was conducted using a 2 (exercise and nonexercise groups) x 3 (baseline, 6-, and 15-wk testing sessions) factorial design, with data analyzed using repeated measures ANOVA. No significant change in NK cell number occurred as a result of ET as measured by the CD16 and Leu-19 monoclonal antibodies. ET did have a significant effect on NK cell activity (E:T 50:1) especially during the initial 6-wk period [F(2.68) = 12.34, p less than 0.001]. Using data from daily logs kept by each subject, the exercise group was found to have significantly fewer URI symptom days/incident than the nonexercise group (3.6 +/- 0.7 vs 7.0 +/- 1.4 days, respectively, p = 0.049). Improvement in cardiorespiratory fitness was correlated significantly with a reduction in URI symptom days/incident (r = 0.37, p = 0.025) and a change in NK cell activity from baseline to six but not 15 wks (r = 0.35, p = 0.036). In summary, moderate ET is associated with elevated NK cell activity after six but not 15 weeks, and reduced URI symptomatology in comparison to a randomized, sedentary control group.

Adult↗
PubMed1990

The relationship among adiposity, diet, and hormone concentrations in vegetarian and nonvegetarian postmenopausal women.

The relationships among anthropometric variables, dietary nutrients, and plasma steroid, polypeptide, and binding-protein hormone concentrations were investigated in 24 Seventh-day Adventist postmenopausal women, 12 vegetarian (SV) and 12 nonvegetarian (SNV). Fasting blood and 7-d dietary intake information were collected. SVs consumed significantly more crude and dietary fiber and fewer saturated fatty acids than did SNVs. The thigh and sum of three skinfold-thickness measurements were significantly greater for SNVs than for SVs. Plasma concentrations of estradiol-17 beta were significantly lower in SVs than in SNVs. Significant relationships were observed for the combined groups (SV and SNV) between estradiol-17 beta and triceps and suprailiac skinfold thickness and body fat. Plasma concentrations of estradiol-17 beta of the combined groups revealed a significant negative relationship between their crude and dietary fiber intakes. Further study delineating the effects of adiposity and dietary nutrients on basal concentrations of sex hormones is warranted.

Adipose Tissue↗