The immune response to prolonged cardiorespiratory exercise.
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Cardiovascular Physiological Phenomena↗
Biomedical subjects
D C Nieman
Publications and source records attributed to D C Nieman.
Comparison of eight microcomputer dietary analysis programs with the USDA Nutrient Data Base for Standard Reference.
OBJECTIVE: To compare the general operating features and nutrient databases of eight microcomputer dietary analysis programs. DESIGN: A 3-day food record with 73 food items was entered into each program by the authors. The general operating features of the program were summarized and evaluated. The nutrient database was evaluated by comparing the nutrient analysis output with the 1993 US Department of Agriculture (USDA) Nutrient Data Base for Standard Reference (NDB), full version, release 10, for microcomputers. RESULTS: The programs varied in cost, number of foods and nutrients in the database, use of non-USDA data, and inputting of data for missing values. We also found differences in the quality of user manuals and help screens, ease of food entry and averaging of 3-day nutrient intake, speed of analyzing and printing results, quality and number of print/export options, and overall ease of learning and using the program. All but one of the programs were within 15% of the USDA NDB for energy, protein, total fat, and total carbohydrates. However, there was some difference in the number of other nutrients and food components varying more than 15% from the USDA NDB. These differences occurred because of variations in the number of food items included in each programs' database and the number of missing nutrient values in the database. APPLICATIONS: Our results demonstrate the importance of carefully choosing a microcomputer dietary analysis program that is suitable to the user's specific and predetermined needs.
Databases, Factual↗
The acute immune response to exhaustive resistance exercise.
Ten young male adults (mean age 46.9 +/- 1.2 yrs) with 9.2 +/- 1.4 years of weight training experience and the ability to parallel squat at least 1.5 times their body mass were selected as subjects. The exercise session consisted of sets of 10 repetitions at 65% 1-RM of the parallel leg squat, with a cadence of one rep every 6 sec and 3 min rest between sets, to muscular failure. The average subject lifted a total of 9711 +/- 1576 kg during 98 +/- 14 reps for a total work output of 72.5 +/- 10.5 kJ before muscular failure occurred. Mean oxygen consumption during exercise was 1.58 +/- 0.06 l/min at 42.5 +/- 2.0% peak VO2. A strong leukocytosis, lymphocytosis, and lymphocytopenia, similar to what has been reported following high-intensity cardiorespiratory exercise, were measured following leg squat exercise. Con A-stimulated lymphocyte proliferation (unadjusted) rose 50% above preexercise levels (p = 0.07), but when these data were adjusted on a per T cell (CD3+) basis, no change from rest was observed. Natural killer cell cytotoxic activity (NKCA), when adjusted on a per NK cell (CD56+) basis, was decreased about 40% below preexercise levels for at least 2 h post-exercise. No significant increase in cortisol was seen after exercise, although norepinephrine and epinephrine increased moderately (465% and 133%, respectively), immediately following exercise. The data demonstrate that leg squat exercise to muscular failure results in a very similar immune response to that associated with intense endurance exercise, despite a lower mean oxygen consumption and only a moderate hormonal response.
Adult↗
Immune function in athletes versus nonathletes.
The purpose of this study was to compare natural killer cell cytotoxic activity (NKCA) and Con A-induced lymphocyte proliferation (T cell function) in athletes versus nonathletes, with measurement of natural killer (NK) and T cells to allow a comparison on a "per-cell" adjusted basis. Eighteen young male endurance athletes (10 runners and 8 cyclists) with a mean VO2max of 70.7 +/- 1.3 ml.kg-1.min-1 and 6.6 +/- 0.8 years of competitive experience were compared with 11 nonathletic male adults (47.6 +/- 3.1 ml.kg-1.min-1). Concentrations of circulating leukocyte and lymphocyte subsets, including NK and T cells, were not significantly different between groups. NKCA and T cell function also did not differ between groups, whether expressed unadjusted or adjusted on a per-cell basis. For all subjects combined, both NKCA and T cell function were unrelated to VO2max (r = 0.005, p = 0.98; r = 0.007, p = 0.97, respectively). These data do not support the contention that immune function, as measured in this study, is altered in endurance athletes.
Adult↗
Moderate exercise training and natural killer cell cytotoxic activity in breast cancer patients.
Sixteen female breast cancer patients who had been diagnosed (3.0 +/- 1.2 years previous to the study) and undergone surgery, chemotherapy, and/or radiation treatment were randomly assigned to exercise and nonexercise groups. Pre- and post-study measurements were taken for aerobic performance, leg strength, and concentrations of circulating lymphocyte subsets and natural killer cell cytotoxic activity (NKCA). Exercise training consisted of 60 minutes of supervised weight training and aerobic activity three times each week for eight weeks. Although subjects in the exercise groups demonstrated some modest improvement in the various aerobic and strength tests, NKCA and concentrations of circulating T and NK cells were not significantly altered relative to the nonexercise group. This study suggests that moderate exercise over an eight-week period has no significant effect on the function of in vitro natural killer cells in breast cancer patients.
Adult↗
Lymphocyte proliferative response to 2.5 hours of running.
The effect of 2.5 h of treadmill running at 75.6 +/- 0.9% VO2max on circulating leukocyte and lymphocyte subpopulations, epinephrine and cortisol concentrations, and the Con A-induced lymphocyte proliferative response was investigated in 22 experienced marathon runners (VO2max 57.9 +/- 1.1 ml.kg-1.min-1, age 38.7 +/- 1.5 yrs). Blood samples were taken 15 min before (07.15h) and immediately after exercise (10.00h), with three more samples taken during 6h of recovery (11.30, 13.00, 16.00h). Ten sedentary controls (34.7 +/- 1.0 ml.kg-1.min-1, 45.3 +/- 2.3 yrs) sat in the laboratory during testing and had their blood sampled at the same time points. Serum cortisol was elevated relative to controls for more than 3 h post-exercise, and correlated significantly with the 3-h post-exercise, and correlated neutrophil/lymphocyte ratio (r = 0.68, p < 0.001). The concanavalin A- (Con A) induced lymphocyte proliferative response was decreased relative to controls for more than 3 h post-exercise, and except for the immediate post-exercise time point, tended to parallel the decrease in T cell (CD3+) concentrations.
Adult↗
Upper respiratory tract infections and exercise.
The epidemiological data suggest that endurance athletes are at increased risk for upper respiratory tract infections during periods of heavy training and the 1-2 week period following a marathon or similar event. At present there is no clear indication that chronic alterations in immune function explain this increased risk. Following acute bouts of prolonged heavy endurance exercise, several components of the immune system are suppressed for several hours. This has led to the concept of the "open window" theory described as the 1-9 hour period following prolonged endurance exercise when host defense is decreased and the risk of upper respiratory tract infection is increased.
Adult↗
Indomethacin does not alter natural killer cell response to 2.5 h of running.
The effect of 2.5 h of treadmill running at 75.6 +/- 0.9% maximal O2 uptake (VO2max) on natural killer (NK) cell cytotoxic activity (NKCA) was investigated in 22 experienced marathon runners (VO2max 57.9 +/- 1.1 ml.kg-1.min-1, age 38.7 +/- 1.5 yr). Blood samples were taken before (0715) and immediately after exercise (1000), with three more samples taken during 6 h of recovery (1130, 1300, and 1600). Ten sedentary controls (VO2max 34.7 +/- 1.0 ml.kg-1.min-1, age 45.3 +/- 2.3 yr) sat in the laboratory during testing and had their blood sampled at the same time points. The pattern of change in NKCA over time was significantly different between groups [F(4,27) = 6.53; P = 0.001], with the runner's NKCA dropping 51-61% below preexercise levels throughout 6 h of recovery. Preincubation of blood mononuclear cells in vitro with indomethacin had no effect on the difference in pattern of change in NKCA between groups [F(4,17) = 8.59; P = 0.001] and did not attenuate the postexercise reduction in the runners. When NKCA was adjusted on a per-NK cell basis, group differences and the postexercise decline in NKCA were eliminated [F(4,80) = 0.65; P = 0.63]. Serum cortisol and plasma epinephrine in the runners were elevated relative to control subjects during recovery from exercise, but no significant correlation with changes in NK cells or NKCA was found. These data indicate that NKCA is decreased significantly during recovery from 2.5 h of running due to a numerical redistribution of NK cells.
Adult↗
Immune function in marathon runners versus sedentary controls.
Marathon runners (N = 22) who had completed at least seven marathons (X +/- SEM = 23.6 +/- 5.7) and had been training for marathon race events for at least 4 yr (12.3 +/- 1.3) were compared with sedentary controls (N = 18). Although the two groups were of similar age (38.7 +/- 1.5 and 43.9 +/- 2.2 yr, respectively) and height, the marathon runners were significantly leaner and possessed a VO2max 60% higher than that of the controls. Neutrophil counts tended to be lower in the group of marathoners, while other leukocyte and lymphocyte subsets were similar to controls. Mitogen-induced lymphocyte proliferation did not differ between groups. Natural killer cell cytotoxic activity (NKCA) was significantly higher in the marathoners versus controls (373 +/- 38 vs 237 +/- 41 total lytic units, respectively, a 57% difference, P = 0.02). For all subjects combined (N = 40) and within the group of marathon runners (N = 22), percent body fat was negatively correlated with NKCA (r = -0.48, P = 0.002; r = -0.49, P = 0.019, respectively), and age was negatively correlated with Con A-induced lymphocyte proliferation (r = -0.41, P = 0.009; r = -0.53, P = 0.011, respectively). These data indicate that NKCA but not mitogen-induced lymphocyte proliferation is higher in marathon runners relative to sedentary controls.
Adult↗
Effect of high- versus moderate-intensity exercise on lymphocyte subpopulations and proliferative response.
The effect of 45 min of high- (80% VO2max) versus moderate- (50% VO2max) intensity treadmill exercise on circulating leukocyte and lymphocyte subpopulations, catecholamine and cortisol concentrations, and the mitogen-stimulated lymphocyte proliferative response was investigated in 10 well-conditioned (mean VO2max 66.0 +/- 1.9 ml/kg/min), young males (mean age 22.1 +/- 1.3 yrs). Blood samples were taken before and immediately after exercise, with three more samples taken during 3.5 h of recovery. Treatment order on the treadmill (graded walking at 7.3 +/- 0.1 km/h, 6.5 +/- 0.6% grade, versus level running at 16.1 +/- 0.3 km/h) was counterbalanced, with subjects acting as their own controls and results analyzed using a 2 x 5 repeated measures ANOVA. The concanavalin A- (Con A) stimulated lymphocyte proliferative response was decreased at 1 h and 2 h post-exercise relative to baseline levels following both exercise-intensity conditions. However, when adjusted on a per-T cell (CD3+) basis to account for the change in number of T cells in the in vivo assay, only the high-intensity exercise condition was associated with a 1-h post-exercise decrease (21%, p = 0.05) in the proliferative response relative to baseline. Exercise at 80% versus 50% VO2max resulted in significantly greater increases in cortisol and epinephrine concentrations, providing a physiological rationale for the immediate-post-exercise lymphocytosis, 1- to 3.5-h lymphocytopenia, and the decrease in Con A-stimulated lymphocyte proliferative response (per CD3+ cell) that occurred in greater measure following high-intensity exercise.
Adolescent↗
Exercise, infection, and immunity.
In this article, emphasis was placed on the relationship between exercise and upper respiratory tract infection (URTI) in humans, experimentally induced infections in animals subjected to varying levels of exertion, and potential changes in the immune system that might explain the altered risk of infection. With regard to induced infections in animals, the influence of any exercise intervention appears to be pathogen specific, and dependent on the species, age, and sex of the animals selected for study, and the type of exercise paradigm. In general, although further research with larger subject pools and improved study designs is needed, published data at this time support a "J" curve relationship between risk of URTI and increasing exercise workloads. For example, individuals exercising moderately may lower their risk of URTI while those undergoing heavy exercise regimens may have higher than normal risk. Although researchers have investigated changes in immune function that might provide a biological rationale for the "J" curve model of infection and exercise, the wide variety of research designs, exercise protocols, subject characteristics, and methodologies combined with the innate complexity of the immune system have made interpretation of published findings equivocal. T and NK cell function, for example, is often reported to be decreased during recovery from high-intensity exercise. However, when adjustments are made for exercise-induced perturbations in blood lymphocyte subsets, any link to decreased host protection is unlikely.
Animals↗
Food intake patterns of marathon runners.
A group of marathon runners (290 males, 54 females, mean age 39.7 +/- 0.7 years) who participated in the Los Angeles Marathon recorded their food and fluid intake throughout a 3-day period, with the time of day denoted for each entry. Investigators coded each subject's food intake according to six time periods: 5:00-8:59 a.m., 9:00-10:59 a.m., 11:00 a.m.-1:59 p.m., 2:00-3:59 p.m., 4:00-7:59 p.m., and 8:00 p.m.-4:59 a.m. The average intake of the runners consisted of 314 +/- 6 g (52.3%) carbohydrates, 83.2 +/- 2.0 g (30.7%) fat, and 99.7 +/- 2.3 g (16.5%) protein. Time periods for breakfast (13.7%), lunch (23.8%), and supper (34.0%) accounted for 71.5% of total caloric intake, with snack time periods contributing 28.5%. Breakfast calories were 68.9 +/- 0.9% carbohydrate and 20.4 +/- 0.7% fat in contrast to supper calories, which were 47.7 +/- 0.8% and 31.8 +/- 0.6%, respectively. A sizable proportion of the daily caloric intake of recreational marathon runners is contributed by snacks and food intake after 4:00 p.m.
Adult↗
The relationship between cardiorespiratory fitness, physical activity, and dietary quality.
This study evaluated the relationship between cardiorespiratory fitness, physical activity, and dietary quality in a group of 20- to 40-year-old women (n = 34) who varied widely in levels of physical activity. Nutrient intakes were determined using 10 repeated 24-hr diet records, randomly assigned, over a 10-week period. Physical activity was determined on the same randomly assigned days using the Caltrac Personal Activity Computer. Cardiorespiratory fitness was assessed by two maximal graded treadmill tests with continuous metabolic monitoring at both the beginning and end of the 10-week period. Neither physical activity nor cardiorespiratory fitness was significantly correlated with nutrient density (nutrient/1,000 kcal). Intake of energy (kcal/kg body weight) was higher for the more physically active and fit women, leading to a significant increase in most nutrients consumed per kilogram of body weight.
Adult↗
Exercise, upper respiratory tract infection, and the immune system.
The relationship between exercise and upper respiratory tract infections (URTI) may be modeled in the form of a "J" curve. Various epidemiological studies suggest that unusually heavy acute or chronic exercise is associated with an increased risk of URTI. The risk appears to be especially high during the one or 2-wk period following marathon-type race events. Among runners varying widely in training habits, the risk for URTI is slightly elevated for the highest distance runners, but only when several confounding factors are controlled for. Two randomized experimental trials using small numbers of subjects have provided important preliminary data in support of the viewpoint that moderate physical activity may reduce URTI symptomatology. Clinical data support the concept that heavy exertion increases the athlete's risk of URTI because of negative changes in immune function and elevation of the stress hormones, epinephrine, and cortisol. On the other hand, there is growing evidence that moderate amounts of exercise may decrease one's risk of URTI through favorable changes in immune function without the negative attending effects of the stress hormones.
Exercise↗
Role of endurance exercise in immune senescence.
The immune system undergoes significant changes with advancing age. The increased incidence of malignancy, infectious disease, and autoimmune disorders with age is felt to be linked with this decline of immunocompetence. The aging process does not uniformly affect the immune system, however, and there is a high degree of individual variation. There is growing evidence that the variation in immune function among the elderly is associated at least in part with environmental factors such as nutritional status and physical activity. Although investigation of the relationship between endurance exercise and immune function in elderly subjects has just recently begun, data from the few studies available are intriguing and have potential for widespread public health influence. These data are reviewed in this paper, with directions given for future research.
Adult↗
The effect of exercise on immune function.
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Exercise↗
The immune response to exercise.
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Antibody Formation↗
The exercise test as a component of the total fitness evaluation.
In this article, physical fitness has been defined as a dynamic state of energy and vitality that enables one to carry out daily tasks, to engage in active leisure-time pursuits, and to meet unforeseen emergencies without undue fatigue. In addition, physically fit individuals are described as being at low risk for hypokinetic diseases and being more able to function at the peak of intellectual capacity while experiencing "joie de vivre." The measurable elements of physical fitness have been categorized into two groups: skill-related fitness and health-related fitness. The former category includes agility, balance, coordination, speed, power, and reaction time. The latter includes cardiorespiratory endurance, body composition, and musculoskeletal fitness, which incorporates flexibility, muscular strength, and muscular endurance. It is highly recommended that clinicians provide comprehensive fitness testing for their patients because of the well-established health-related benefits that are related to each component.
Body Composition↗