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Biomedical subjects

D C Nieman

Publications and source records attributed to D C Nieman.

107 records · Page 6Linked to original sources
PubMed1990

Reducing-diet and exercise-training effects on serum lipids and lipoproteins in mildly obese women.

Twenty-one mildly obese women were fed a 1268-kcal lactovegetarian diet for 5 wk. Subjects were randomly divided into either an exercise (Ex) or a nonexercise (Nex) group. The Ex group walked at 60% heart-rate reserve (134 +/- 2 bpm; mean +/- SEM) during 45-min sessions, five times per week. Although exercise improved estimated maximum oxygen consumption (VO2max; 20.9 +/- 3.2% vs 2.1 +/- 3.4% in Ex vs Nex, respectively), changes in total body, lean body, and fat weight did not differ significantly between groups. Total body weight decreased 5.5 +/- 0.6 and 5.6 +/- 0.2 kg in Ex and Nex, respectively. Statistical analysis revealed significant differences in the pattern of change between groups for serum high-density-lipoprotein cholesterol (HDL-C; F[2,38] = 5.93, P = 0.006) but not for total cholesterol (TC), low-density-lipoprotein cholesterol, triglycerides, or glucose. Change in diet quality and body weight were found to account fully for the 12.7 +/- 1.9% decrease in TC. When change in dietary quality and body weight are equated in a group of mildly obese women, the effect of moderate exercise training on indices of serum lipid and lipoprotein is limited to HDL-C.

Body Composition↗
PubMed1990

The effects of moderate exercise training on nutrient intake in mildly obese women.

The relationship between moderate exercise training (five 45-minute sessions per week, brisk walking at 62 +/- 2% VO2 max for 15 weeks) and changes in nutrient intake was investigated in a group of 36 sedentary, mildly obese women. The study was conducted using a 2 x 3 factorial design (two groups of subjects: exercise and nonexercise groups; three periods: baseline, 6-week, and 15-week testing sessions). Data were analyzed using repeated measures ANOVA. The pattern of change in caloric intake over time tended to be different between groups (F[2, 68] = 2.50, p = .089); the exercise group experienced a significant decrease in caloric intake by 15 weeks. Significant group x time interactions were found for intakes of carbohydrate, dietary fiber, thiamin, niacin, vitamin B-6, and folate. Intake tended to decrease in the exercise group and to increase in the nonexercise group. Change in intake of each of these nutrients was significantly correlated with change in bread and cereal consumption. The pattern of change in bread and cereal intake over time was significantly different between groups (Pillais Trace = 0.266, F[2, 33] = 5.99, p = .006); the exercise group had significant decreases in intake at 6 and 15 weeks vs baseline values. These data suggest that mildly obese women reduce energy intake subsequent to initiating an exercise program; concomitantly there is a decrease in the quality of nutrient intake from their diets compared with those of sedentary controls.

Adult↗
PubMed1990

Infectious episodes in runners before and after the Los Angeles Marathon.

An epidemiologic study of Los Angeles Marathon (LAM) applicants was conducted to investigate the relationship between self-reported infectious episodes (IE), training data, and LAM participation. Eight days before the LAM, 4926 of 12,200 applicants were randomly selected, and sent a pilot-tested four page questionnaire, which was received 7 days after the LAM. The 2311 respondents were found to be 2.0 yr older and 7.6 min faster than other LAM finishers (p less than .01). Univariate and multivariate analyses (logistic regression) were conducted to test the relationship between IE and km/wk of running (6 total categories). The final model tested controlled for age, marital status, reported sickness in other members of the runner's home, perceived feelings of stress in response to personal training regimens, and the suppressive effect of sickness on regular training. In runners training greater than or equal to 97 vs less than 32 km/wk, the odds ratio (OR) for IE during the 2 month period prior to the LAM was 2.0 (95% confidence interval (CI) 1.2-3.4). A test for trend showed an increase in OR with increase in km/wk category (p = .04) which was largely explained by the increased odds of reported sickness in the greater than or equal to 97 km/wk category. Of the 1828 LAM participants without IE before the LAM, 236 (12.9%) reported IE during the week following the LAM vs 3 of 134 (2.2%) similarly experienced runners who did not participate, OR = 5.9 (95% CI 1.9-18.8). These data suggest that runners may experience increased odds for IE during heavy training or following a marathon race.

Adult↗
PubMed1990

The effect of long endurance running on natural killer cells in marathoners.

Ten experienced marathoners were exercised 3 h in the laboratory. Blood samples were collected at 0 h baseline, 1 h exercise, and 5 min, 1.5 h, 6 h, and 21 h recovery and were analyzed for total number of lymphocytes expressing membrane antigens found on natural killer (NK) cells. NK activity was also measured. Four of the seven subpopulations of lymphocytes studied, Leu-11+19+, Leu-11+19-, Leu-11+7-, and Leu-19+11-, showed significant within-subject effects over time, using repeated measures ANOVA. Simple contrasts with baseline values showed that, at 1.5 h and 21 h recovery, total number of lymphocytes bearing three different combinations of NK markers, Leu-11+19+, Leu-11+19-, and Leu-11+7-, were significantly decreased when compared with baseline values. At 1.5 h recovery, NK activity was significantly decreased below baseline levels for four of the six effector NK cell/target K562 myelogenous leukemia cell (E:T) ratios tested. At 6 h recovery, NK activity was still decreased significantly with the 12.5:1 and 3:1 E:T ratios. By 21 h recovery, NK activity did not differ significantly from baseline levels. Cortisol levels at 5 min post-exercise were negatively correlated with NK activity at 1.5 h recovery (r = -0.62, P = 0.05, 50:1 E:T ratio; r = -0.66, P = 0.04, 25:1 E:T ratio). Further research is needed to elucidate the effect these changes have on host immunosurveillance and immunoresponsiveness in vivo.

Epinephrine↗
PubMed1989

Complement and immunoglobulin levels in athletes and sedentary controls.

Eleven marathon runners (42.7 +/- 2.1 yrs, 54.2 +/- 1.8 ml.kg-1.min-1) and nine sedentary controls (44.2 +/- 1.2 yrs, 33.3 +/- 1.1 ml.kg-1.min-1) were studied during 30 min of rest, a graded maximal treadmill test using the Balke protocol, and 45 min of recovery to determine the effects of training and acute exercise on complement and immunoglobulin levels. Three baseline and five recovery blood samples were obtained in addition to repeated 5-min samples during exercise. Data for the exercise period were analyzed using a multiple regression approach to repeated measures ANOVA to allow comparison between groups on a percent VO2max basis. Groups did not differ during any of the three phases for IgG, IgA, or IgM. Resting levels of complement C3 (0.89 +/- 0.05 vs 1.27 +/- 0.10 g/L, P less than 0.001) and C4 (0.19 +/- 0.02 vs 0.29 +/- 0.03 g/L, P less than 0.001) were significantly lower in athletes than in controls. Exercise complement C3 [F(1,18) = 14.1, P = 0.001] and C4 [F(1,18) = 7.6, P = 0.013], and recovery complement [F(1,18) = 19.4, P less than 0.001] and C4 [F(1,18) = 13.5, P = 0.002] were also lower in the athletes than in sedentary controls. Acute increases during exercise were not associated with changes in catecholamines or cortisol. These data suggest that blood concentrations of C3 and C4, but not IgG, IgA, or IgM, are decreased during rest, graded maximal exercise, and recovery in marathon runners in comparison with sedentary controls.

Adult↗
PubMed1989

Hematological, anthropometric, and metabolic comparisons between vegetarian and nonvegetarian elderly women.

The purpose of this study was to investigate hematological, anthropometric, and metabolic differences in elderly women who were similar in most respects except for choice of diet. Nineteen vegetarian (V) and 12 non-vegetarian (NV) elderly women (mean ages 72.3 +/- 1.4 and 69.5 +/- 1.0 years, respectively) were recruited based on several selection criteria including race, religion, education, Quetelet Index, absence of major chronic disease and use of medications, physical activity, and geographic area. Average years of adherence by V and NV groups to dietary regimens were 46.3 +/- 3.3 and 69.6 +/- 1.0, respectively; Hematological comparisons revealed that the V elderly women had significantly lower glucose (4.60 +/- 0.09 vs 5.13 +/- 0.11 mmol/L), low-density lipoprotein cholesterol (3.14 +/- 0.19 vs 4.09 +/- 0.27 mmol/L) and total cholesterol levels (5.41 +/- 0.20 vs 6.48 +/- 0.29 mmol/L) than the NV elderly women (P less than 0.01) for each. The V elderly women tended to have less body fat and midupper arm muscle area than the NV. No differences between groups were found in a variety of metabolic and electrocardiographic parameters during graded maximal treadmill testing except for lower heart rates in the V women. VO2max was not significantly different between the V and NV elderly women (23.8 +/- 1.5 vs 21.9 +/- 0.8 ml.kg-1.min-1, respectively). In summary, when healthy elderly V women are compared with closely matched NV peers, the vegetarian diet is associated with several benefits, primarily lower blood glucose and lipid levels, but not greater functional capacity.

Aged↗
PubMed1989

Effects of long-endurance running on immune system parameters and lymphocyte function in experienced marathoners.

The extent and duration of changes in leukocyte subsets, lymphocyte subpopulations, spontaneous blastogenesis, cortisol, and catecholamines were measured in ten experienced marathoners, who ran 3 h to exhaustion in a laboratory setting. Blood samples were taken at baseline, 1 h of exercise, and 5 min, 1.5 h, 6 h, and 21 h of recovery. The 3-h endurance run was associated with significant leukocytosis, granulocytosis, neutrophilia, monocytosis, and eosinopenia during recovery. All of these parameters except for eosinophils returned to normal by 21 h of recovery. Total lymphocyte count increased 31% at 1 h of exercise, then decreased 19% at 1.5 h of recovery when compared with baseline values. T cell count showed no significant changes, but B cell lymphocytosis was measured at 5 min and 6 h of recovery. T helper/T suppressor ratio (H/S) was significantly elevated 39% at both 1.5 h and 21 h of recovery due to the decrease in number of T suppressor cells. Spontaneous blastogenesis was significantly increased 52% by 1 h of exercise and remained elevated throughout recovery. The increase in cortisol from baseline to 1.5 h of recovery correlated positively with the increase in both total leukocyte count (r = 0.78, P = 0.008) and granulocyte count (r = 0.81, P = 0.005). Our results suggest that exhaustive endurance exercise in marathon runners is associated with many significant perturbations in immune system parameters, most of which return to normal levels at 21 h of recovery.

Adult↗
PubMed1989

Nutrient intake of marathon runners.

Three-day food records from a large group of marathon runners (291 men, 56 women) were analyzed and compared to various standards of dietary quality. Intake by the runners exceeded two-thirds of the Recommended Dietary Allowance for all nutrients except vitamin D and zinc in female runners. Energy and nutrient intake levels in the marathon runners were higher than those of the general U.S. population except for total fat, vitamin B-12, and zinc in both men and women and sodium in men. In general, runners consumed better diets than the general population. However, both caloric intake and percent energy as carbohydrate were lower than recommended for individuals engaging in endurance exercise. The need for professional help in planning high-carbohydrate diets for runners is indicated. Increasing amounts of training were not associated with significant increases in nutrient densities across three activity categories within this group of runners. However, more than 75% of the runners perceived their diets to be much improved after they began regular training (men 8.2 +/- 0.3 years of running experience, women 6.7 +/- 0.6). Together, these data suggest that regular moderate-to-heavy endurance exercise is associated with a better quantity and quality of nutrient intake than that found in the general population, which may in part be related to the adoption of such exercise by previously sedentary individuals.

Adult↗
PubMed1989

Dietary status of Seventh-Day Adventist vegetarian and non-vegetarian elderly women.

The purpose of this study was to investigate nutrient intakes of Seventh-Day Adventist elderly women who were similar in many demographic and life-style factors except for choice of diet. Twenty-three vegetarian and 14 non-vegetarian elderly women (mean +/- standard error ages 72.2 +/- 1.3 and 71.1 +/- 1.4 years, respectively) were recruited on the basis of several selection criteria, including race, religion, education, geographic area, Quetelet index, self-reported absence of major chronic disease and use of medications, and physical activity. Average years +/- SE of adherence to dietary regimens were 47.0 +/- 2.9 and 71.2 +/- 1.4 in the vegetarian and non-vegetarian groups, respectively. Results from analysis of 7-day food records showed that vegetarians consumed significantly less cholesterol, saturated fatty acids, and caffeine but more carbohydrate, dietary fiber, magnesium, vitamins E and A, thiamin, pantothenic acid, copper, and manganese than non-vegetarians (p less than .05). On the basis of group means, 67% of the Recommended Dietary Allowance was met for all nutrients except zinc and vitamin D in both groups, and vitamins B-6, folacin, and vitamin E in the non-vegetarians. Compared with non-vegetarians, vegetarians had significantly lower serum glucose (5.18 +/- 0.11 vs. 4.65 +/- 0.09 mmol/L), low-density-lipoprotein cholesterol (4.08 +/- 0.25 vs. 3.34 +/- 0.19 mmol/L), and total cholesterol levels (6.46 +/- 0.27 vs. 5.62 +/- 0.21 mmol/L) (p less than .05). In summary, when healthy elderly vegetarian women were compared with closely matched non-vegetarian peers, the vegetarian diet was associated with improved nutrient intake and associated reductions in blood glucose and lipid levels.

Aged↗
PubMed1989

Infectious episodes in runners before and after a roadrace.

Various researchers have implied that regular and moderate exercise training may improve the ability of the immune system to protect the host from infection. In contrast, acute, maximal, and exhaustive exercise may have negative effects of the immune system. This study compared the incidence of infectious episodes in 273 runners during a two month training period prior to a 5 K, 10 K, or half-marathon race. In addition, the effect of the race experience on infectious episodes was studied. Twenty-five percent of the runners training more than 15 miles per week reported at least one infectious episode as compared with 34.3% of runners training less than 15 miles per week (p = 0.09). Only 6.8% of the runners preparing for the half-marathon race reported becoming sick with the flu versus 17.9% of the 5 K and 10 K runners (p = 0.067). During the week following the roadrace, runners did not report an increase in infectious episodes as compared to the week prior to the race. These trends suggest that runners with a more serious commitment to regular exercise may experience less infectious episodes than recreational runners because of both direct and indirect affects on immunosurveillance. In addition, the stressful race experience does not appear to increase risk of acquiring an acute respiratory infection.

Adult↗
PubMed1989

Supplementation patterns in marathon runners.

The purpose of the present investigation was to study the use of supplements in a large group of endurance runners (no. = 347) who had participated in the 1987 Los Angeles Marathon. Three-day dietary records were analyzed for nutrient content and supplement usage. The runners' supplementation patterns with respect to demographics, dietary quality, training habits, and race performance were investigated. In general, no significant associations were found between supplement use and the aforementioned variables. Use of supplements, especially vitamins C and E, calcium, and zinc, increased with age (p less than .05). Daily use of at least one type of supplement was reported by 29% of the runners; 48% reported use of at least one type of supplement within the 3-day period.

Adult↗
PubMed1988

Vegetarian dietary practices and endurance performance.

Confounding influences of varying fat, protein, and carbohydrate (CHO) levels, training habits, and lifestyle patterns make the interpretation of specific influences of the diet on endurance performance unclear. In general, exhaustion during prolonged, hard endurance exercise is tied to low muscle glycogen stores. Athletes in heavy training are urged to consume 70% of calories as CHO to maximize body CHO stores. A deemphasis in animal products with an emphasis in high-CHO plant foods would facilitate athletes in conforming to nutritional recommendations. Some female athletes may increase their risk of iron deficiency and/or amenorrhea if a restrictive vegetarian diet is adopted. In general, the high-CHO nature of the vegetarian diet can help the endurance athlete in heavy training maximize body glycogen stores and thus the ability to perform. The balanced vegetarian diet provides the athlete with added reduction in coronary risk factors while meeting all known nutritional needs.

Diet↗
PubMed1987

Running endurance in 27-h-fasted humans.

Nine male marathon runners were exercised to exhaustion to determine the effects of a 27-h fast on endurance performance. Each subject completed two exercise tests at the same treadmill speed (set at 70% maximal O2 uptake), one following a 27-h fast and one 3 h after a preexercise meal, in random order. Fasting caused a 44.7 +/- 5.8% (SE) decrease in endurance performance (P less than 0.01). Blood, muscle, psychological, and ventilatory data were examined to determine the cause of the decreased performance. Fasting caused significant increases in O2 uptake (9.3 +/- 2.0%), heart rate (8.4 +/- 2.4%), and rating of perceived exertion, ventilation, and psychological fatigue, evident within the first 60 min of exercise. There were no differences in plasma glucose or epinephrine levels. Muscle glycogen degraded at the same rate (0.482 +/- 0.146 vs. 0.470 +/- 0.281 mumol.g-1.min-1 in the nonfasted and fasted tests, respectively) despite lower respiratory exchange ratio and elevated free fatty acid levels, which may partially explain the elevated O2 uptake. Lactate, insulin, and norepinephrine were all increased in the fasted test (P less than 0.05). The increase in norepinephrine (r = 0.79, P less than 0.01), the diameter of type I muscle fibers (r = 0.70, P less than 0.05), and ending insulin levels (r = -0.88, P less than 0.01) were correlated with endurance time in the fasted state. Fatigue in endurance running for 27-h fasted humans appears to be related to a combination of physiological, psychological, metabolic, and hormonal changes.

Adult↗
PubMed1987

A comparative study of two microcomputer nutrient data bases with the USDA Nutrient Data Base for Standard Reference.

The results of this investigation show that when direct comparisons are made between the USDA NDB and microcomputer data bases (avoiding the confounding factors of coding judgment and the differences between older and newer USDA nutrient data), differences still can exist. N3 and FP chose to seek out alternate data when the USDA NDB provided no data for a certain nutrient. FP chose to use a large number of additional sources to supplement USDA Handbook No. 8. Although the USDA NDB was very complete for all nutrients listed except for vitamin E/total and copper, gaps are likely to continue to exist because the USDA NDB is and will be in continual revision as an increasing number of nutrients are reported for an ever-growing food supply. Therefore, in accordance with established local needs, the dietitian has the responsibility both for knowing the sources used in the microcomputer nutrient data base and for making sure that reported results are reasonable.

Computers↗
PubMedDate not supplied

Accuracy of a piezoelectric crystal microphone interfaced through an audio amplifier board for use in an automated blood pressure device.

Two certified blood pressure technicians and a computerized blood pressure monitor from Computerized Screening, Inc., model 2000 (CSI 2000) obtained 900 blood pressure (BP) readings from 100 subjects aged 15 to 85 years (mean = 44.1 +/- 1.8 SEM). Measurements were obtained simultaneously on the same limb by the observers and the CSI 2000 three times per subject within a 30-minute period). Pressures obtained from the CSI 2000, which uses a piezoelectric crystal microphone interfaced through a newly designed audio amplifier board, were compared with the results of indirect cuff mercury sphygmomanometry. Correlations between the CSI 2000 readings and simultaneous readings obtained by two certified BP technicians for systolic and diastolic BP were r = 0.96 (p less than 0.001) and r = 0.91 (p less than 0.001), respectively. For systolic BP readings, the estimating equation (least-squares) based on a linear relationship between measurements from the test and reference methods was: CSI 2000 systolic BP = -3.454 + [1.015 x (observers' systolic BP)]. For diastolic BP readings, the estimating equation (least squares) was: CSI 2000 = 5.997 + [0.906 x (observers' diastolic BP)]. Close agreement was found between the readings obtained by the CSI 2000 and the average of those obtained by the two certified BP technicians.

Acoustics↗