Exercise Immunology Applied to Pediatric Sport and the Importance of Monitoring Stages of Puberty and Biological Maturation.

CONTEXT: Exercise immunology is aimed at understanding how exercise sessions can affect the immune system in athletic subjects of different age groups. The objective of the current study was to discuss in which stage of biological maturation (BM) young athletes may be more vulnerable in relation to the immune system, and whether there is a BM range in which it is safer to perform sports training with strenuous exercise loads. EVIDENCE ACQUISITION: Evidence from scientific research from several scientific disciplines (eg, immunology, sport immunology, pediatrics, sports medicine, human development) was gathered to holistically examine the main particularities of exercise immunology as applied to pediatric sport. STUDY DESIGN: Narrative review. LEVEL OF EVIDENCE: Level 5. RESULTS: In pediatric patients, lymphoid tissue expands during puberty and involutes after puberty until it returns to pre-expansion values. This suggests that there is a specific period in which the immune system may be stronger, which may provide opportunities for strenuous exercise in pediatric athletes. However, the chronological period when puberty occurs will be determined by BM, which is the rate at which the biological systems of the human body improves. This may affect the period of lymphoid tissue expansion and, consequently, the behavior of the immune system in pediatric subjects of the same age category. CONCLUSION: During puberty, there is a significant increase in the proinflammatory profile; to compensate for this, there is an expansion of lymphoid tissue that may favor the efficiency of the immune system. The period in which puberty is reached may vary according to the stages of BM. Therefore, in exercise immunology applied to pediatric sports, in addition to external and internal training loads, it is necessary to consider BM and puberty, which have been shown to be safer biomarkers than chronological age for determining immune system behavior in pediatric athletes. STRENGTH-OF-RECOMMENDATION TAXONOMY (SORT): Evidence B level 3.

Influence of age and fitness level on immune responses of T and NK cells in healthy physically active subjects after strenuous aerobic exercise: a cross-sectional study.

Aim: The aim of this study is to analyze whether immune responses after strenuous exercise are influenced by chronological age and fitness level in physically active healthy men. Methods: Cross-sectional study with a sample of 32 physically active men. Participants were divided into two groups based on chronological age (younger: age 21.8 ± 1.8 vs. older: age 34.6 ± 8.3) and subsequently regrouped and divided based on fitness level (More conditioned: excellent and superior VO2max vs. Less conditioned: VO2max: weak, regular and good). Fitness was classified according to VO2max levels obtained by a treadmill test using a gas analyzer. Before and immediately after the ergospirometry test, blood samples were collected for evaluation of immunological markers: leukocytes, neutrophils, lymphocytes and subpopulations. Results: Chronological age had a moderate effect on CD3+CD4+ lymphocyte count (effect size: 0.204) and CD4/CD8 ratio (effect size: 0.278), favoring older subjects. The level of physical fitness had no significant effect on the analyzed immunological markers. Conclusions: Immune responses observed immediately after strenuous exercise may be more dependent on chronological age than on fitness level in healthy, physically active men.

Association between Intensity Levels of Physical Activity and Glucose Variability among Children and Adolescents with Type 1 Diabetes.

Studies would indicate a reduction in hemoglobin A1c levels following moderate and/or vigorous physical activity (PA) for people managing diabetes. However, prior investigations rarely looked at glucose variability in an adolescent population. PURPOSE: The purpose of this investigation was to test the relationship between physical activity intensity levels and glucose variability in a sample of adolescents with type 1 diabetes mellitus, and if the amount of time accumulated for each intensity level is predictive of changes in glucose variability. METHODS: Glucose variability was determined using continuous glucose monitor data and physical activity intensity time was retrieved through Fitabase®. Both glucose and physical activity data were collected over a two-week timeframe. Data analysis was completed using Pearson's correlation and a simple linear regression with a p-value of 0.05 to determine significance. RESULTS: A significant inverse relationship was observed (p = 0.04) between glucose variability and average minutes of daily moderate-intensity activity (r = -0.59), as well as moderate and vigorous physical activity (MVPA) combined (r = -0.86; p = 0.03). A simple linear regression indicated that only MVPA was a significant predictor of glucose variability (ß = -0.12; 95% CI: -0.23--0.01, p = 0.03). CONCLUSION: These data demonstrated that the total amount of daily physical activity is important when properly managing type 1 diabetes mellitus, but time spent in MVPA over two weeks may have an inverse relationship with glucose variability in children and adolescents over a span of two weeks.

Integration of Consumer-Based Activity Monitors into Clinical Practice for Children with Type 1 Diabetes: A Feasibility Study.

Current technology commonly utilized in diabetes care includes continuous glucose monitors (CGMs) and insulin pumps. One often overlooked critical component to the human glucose response is daily physical activity habits. Consumer-based activity monitors may be a valid way for clinics to collect physical activity data, but whether or not children with type 1 diabetes (T1D) would wear them or use the associated mobile application is unknown. Therefore, the purpose of this study was to test the feasibility of implementing a consumer-based accelerometer directly into ongoing care for adolescents managing T1D. METHODS: Adolescents with T1D were invited to participate in this study and instructed to wear a mobile physical activity monitor while also completing a diet log for a minimum of 3 days. Clinical compliance was defined as the number of participants who were compliant with all measures while also having adequate glucose recordings using either a CGM, insulin pump, or on the diet log. Feasibility was defined as >50% of the total sample reaching clinical compliance. RESULTS: A total of 57 children and teenagers between the ages of 7 and 19 agreed to participate in this study and were included in the final analysis. Chi-square results indicated significant compliance for activity tracking (p < 0.001), diet logs (p = 0.04), and overall clinical compliance (p = 0.04). CONCLUSION: More than half the children in this study were compliant for both activity monitoring and diet logs. This indicates that it is feasible for children with T1D to wear a consumer-based activity monitor while also recording their diet for a minimum of three days.

Association between Physical Activity and Sport Participation on Hemoglobin A1c Among Children and Adolescents with Type 1 Diabetes.

PURPOSE: To determine associations between physical activity (PA) and sport participation on HbA1c levels in children with type 1 diabetes (T1D). METHOD: Pediatric patients with T1D were invited to complete a PA and sport participation survey. Data were linked to their medical records for demographic characteristics, diabetes treatment and monitoring plans, and HbA1c levels. RESULTS: Participants consisted of 71 females and 81 males, were 13 ± 3 years old with an average HbA1c level of 8.75 ± 1.81. Children accumulating 60 min of activity 3 days or more a week had significantly lower HbA1c compared to those who accumulated less than 3 days (p < 0.01) of 60 min of activity. However, there was no significant difference in HbA1c values based on sport participation groups. A multiple linear regression model indicated that PA, race, age, duration of diagnosis, and CGM use all significantly predicted HbA1c (p < 0.05). CONCLUSION: This study demonstrated the significant relationship between daily PA and HbA1c. Those in this sample presented with lower HbA1c values even if accumulating less than the recommended number of days of activity. Further, it was shown that sport participation alone may not be adequate enough to impact HbA1c in a similar manner.

Mobile App Use in Adults with Comorbid Type 2 Diabetes and Depression.

The purpose of this preliminary study was to determine smartphone usage, expressed level of interest, and intent to use mHealth apps among adults with comorbid type 2 diabetes (T2D) and depression. A convenience sample of adults (N=35) completed a Demographic and Mobile App Survey and the CESD-R-10. A majority reported using mobile apps (n=23, 65.7%) and felt comfortable or very comfortable using mobile apps (n=14, 46.7%). However, few respondents used a health app (n=6, 17.1%) or a diabetes-specific app for diabetes management (n=3, 8.6%). Adjusted, age and education were the two variables that independently impacted app use; those aged less than 55 years as well as those with a graduate degree were more likely to use apps. Being younger and having an advanced degree increased the odds of using a diabetes-specific app. The findings suggest that adults with T2D are amenable to using mHealth apps to manage diabetes.

Physiology Understanding Week in a public middle school in Southern Indiana: exercise and health.

The Physiology Understanding (PhUn) Week is a national outreach event sponsored by the American Physiological Society. Our PhUn team conducted an event for 551 students (12.5 ± 0.9 yr old) in a middle school in Indiana. The aims of this program were to: 1) teach about the negative consequences of inactivity on cardiovascular (CV) health and overall well-being; 2) help students to determine their own CV fitness level and design their fitness plan; and 3) test the hypothesis that students who are offered daily physical education (PE) classes are able to meet the Physical Activity Guidelines for Americans. The University of Louisville PhUn team visited the school during school hours to execute the outreach program to students enrolled in Health and PE as their course elective. During the event, students were educated about CV physiology and the effects of exercise on CV fitness and metabolism. Additionally, students were asked to completed a questionnaire about their physical activity behaviors outside the school. Students were also educated about ways to increase energy expenditure by 150 METy (units of metabolism for youth) per day during 7 days. CV fitness levels were estimated by using the PACER (Progressive Aerobic Cardiovascular Endurance Run) test, and students were asked to create a plan to increase energy expenditure daily. The results showed that 53% of the students did not perform enough physical activity outside school to meet the guidelines. In conclusion, the incorporation of PE in schools is critical to cultivate healthy lifestyles and decrease the sedentarism epidemic in the U.S.

Predicting Nocturnal Hypoglycemia with Measures of Physical Activity Intensity in Adolescent Athletes with Type 1 Diabetes.

For someone managing type 1 diabetes, understanding their body's glucose response to physical activity could aid in effectively addressing nocturnal hypoglycemia. The purpose of this investigation was to examine the acute temporal associations between blood glucose and measures of moderate-vigorous physical activity (MVPA) through an accelerometer. Ten adolescent athletes with type 1 diabetes wore an accelerometer and continuous glucose monitor (CGM) consecutively for a minimum of 2 weeks. Physical activity was analyzed according to intensity indicating time spent in light, moderate, and vigorous intensities. Hypoglycemic episodes were defined as two successive CGM readings <70 mg/dL, at 5-min intervals, with an episode ending with at least two CGM readings >70 mg/dL. Incidence of nocturnal hypoglycemia occurred during 29% of the nights measured with an average duration of 52.33 ± 41.04 min. When combining total minutes of moderate and vigorous intensities a significant difference was observed between combined MVPA and number of nocturnal hypoglycemic episodes (62.92 min vs. 49 episodes, P = 0.02). Moderate intensity activity alone was not significant in predicting hypoglycemic events or duration. Vigorous intensity physical activity was a significant predictor of nocturnal hypoglycemia after controlling for sedentary and light intensity minutes, age, and gender (ß = 0.21, P = 0.01) with an average time of 26 min of vigorous intensity. Engaging in vigorous intensity physical activity increased the risk of prolonged nocturnal hypoglycemia in adolescent athletes with type 1 diabetes. Incorporating accelerometers into patient care could prove beneficial when making further recommendations for athletes.

Musculoskeletal Outcomes from Chronic High-Speed, High-Impulse Resistance Exercise.

While bones and muscles adapt to mechanical loading, it appears that very specific types of stimuli must be applied to achieve osteogenesis. Our study assessed musculoskeletal outcomes to 30 training sessions on an Inertial Exercise Trainer (Newnan, GA). Subjects (n=13) performed workouts with their left leg, while their right served as an untreated control. Workouts entailed three 60-s sets each of knee extension, hip extension and calf press exercises, separated by 90-s rests. Before and after the 30 training sessions, subjects underwent strength tests (knee and ankle extensors of both legs), DEXA scans (hip, knee and ankles of both legs), and blood draws. After 30 training sessions 2×2 ANOVAs showed left leg peak torques rose significantly. 2×2 ANCOVAs, with bone scan area as a covariate, showed significant left leg calcaneal bone mineral content (+29%) and density (+33%) increases after 30 training sessions. A significant decline in C-terminal telopeptides of type I collagen, a blood marker of bone resorption, also occurred after 30 training sessions. The Inertial Exercise Trainer's large volume of training session repetitions elicited high peak force, peak acceleration and impulses that likely provided a mechanical loading stimulus that evoked calcaneal accretion.

Exercise and Positive Living in Human Immunodeficiency Virus/AIDS.

Evidence would suggest that regardless of disease status, people living with human immunodeficiency virus (HIV)/AIDS can obtain similar health benefits from routine physical activity reported within general populations. Research has shown significant improvements among psychological and physiologic variables within the first 5 to 6 weeks of beginning a routine physical activity program. Daily activity has shown promising results in other clinical populations, but there is still a paucity of research that limits evidence among the HIV population. Additional research is needed to examine the long-term benefits of physical activity, and to discover more practical ways to achieve this lifestyle change.

Health Benefits of Exercise for People Living With HIV: A Review of the Literature.

With life expectancy increasing and the symptomatology of HIV being altered since the advent of antiretroviral therapy (ART), we now have begun to see metabolic changes with negative implications among people living with HIV/AIDS (PLWHA). Some of these changes include increased blood lipids, central fat accumulation, lipodystrophy, and decreased aerobic capacity. All of which are known risk factors for cardiovascular disease, cancer, and all-cause mortality. A common practice among healthy and other clinical populations to help modify these risk factors is some form of aerobic exercise, resistance exercise, or a combination of both. It has been demonstrated that PLWHA could respond in a similar manner, which in turn may enhance life expectancy and/or quality of life. The purpose of this literature review was to examine the evidence of health benefits of routine exercise training among PLWHA since the advent of ART. Although limited in strength because of small sample sizes and limited intervention durations, there is overall consistency in the general findings. An overview of the findings would indicate that physical activity and exercise are both safe and effective in improving cardiorespiratory fitness, metabolic profile, and quality of life among PLWHA.

Association of Markers of Inflammation with Sleep and Physical Activity Among People Living with HIV or AIDS.

This study examined associations of sleep and minutes spent in moderate-vigorous physical activity (MVPA) with C-reactive protein (CRP) and interleukin (IL)-6 among persons living with HIV. Cross-sectional analyses (n = 45) focused on associations of inflammatory outcomes (i.e., CRP and IL-6) with actigraph-derived sleep duration, latency, and efficiency; sleep onset; wake time; and wake-after-sleep-onset; as well as MVPA. Least square means for CRP and IL-6 by levels of sleep and MVPA were computed from general linear models. Individuals below the median of sleep duration, above the median for sleep onset, and below the median of MVPA minutes had higher CRP or IL-6 levels. Generally, individuals with both low MVPA and poor sleep characteristics had higher inflammation levels than those with more MVPA and worse sleep. Understanding the combined impact of multiple lifestyle/behavioral factors on inflammation could inform intervention strategies to reduce inflammation and therefore, chronic disease risk.

Association of exercise heart rate response and incidence of hypertension in men.

OBJECTIVE: To examine the association of heart rate (HR) responses at rest, during exercise, and after exercise with incident hypertension (HTN) in men. PARTICIPANTS AND METHODS: A total of 10,418 healthy normotensive men without abnormalities on electrocardiography or a history of myocardial infarction, stroke, cancer, or diabetes underwent a maximal exercise test and were followed up for incidence of HTN. Heart rate reserve was defined as the maximal HR minus resting HR. Heart rate recovery was defined as HR 5 minutes after the exercise test. RESULTS: During a mean follow-up of 6 years, there were 2831 cases of HTN. Compared with men who had lower HR reserve, the risk of incident HTN was significantly lower for men with higher HR reserve (hazard ratio, 0.84; 95% CI, 0.74-0.95 for the highest quartile vs the lowest quartile of HR reserve; P=.002) when adjusted for age, baseline examination year, smoking, heavy drinking, body mass index, resting blood pressure, cholesterol and glucose levels, and cardiorespiratory fitness. Compared with men who had higher HR recovery, the risk of incident HTN was significantly lower for men with lower HR recovery (hazard ratio, 0.90; 95% CI, 0.80-0.99 for quartile 3 vs highest quartile; P=.04) after adjusting for the aforementioned confounders. However, the overall linear trend for HR recovery was not significant (P=.26). CONCLUSION: The risk of HTN decreased in men with higher HR reserve. Therefore, HR reserve may be considered as a useful exercise parameter for predicting the risk of HTN in men.

Associations between physical activity and sedentary time on components of metabolic syndrome among adults with HIV.

Recent data show that people living with HIV/AIDS (PLWHA) are at a greater risk of cardiovascular disease (CVD), which could possibly be explained by an increased prevalence of metabolic syndrome (MetSyn) due to the known toxicities associated with antiretroviral therapy (ART). The purpose of this study is to examine the relationships between physical activity (PA) and components of MetSyn in a sample of PLWHA taking ART. A total of 31 males and 32 females living with HIV and currently taking ART were enrolled in a home-based PA intervention aimed to reduce risk factors for CVD. Clinical assessments included measures of resting blood pressure (BP), waist circumference, height, weight, PA levels via accelerometer, and a fasted blood draw. Components of MetSyn were divided into three clusters (1 = 0-1; 2 = 2; 3 = 3 or more). A one-way analysis of variance was used to determine differences between clusters. Multiple linear regressions were used to identify significant associations between moderate intensity PA (MPA) and sedentary time among components of MetSyn. MPA was significantly lower across MetSyn clusters (p < 0.001), whereas sedentary time was significantly higher (p = 0.01). A multiple linear regression showed MPA to be a significant predictor of waist circumference after controlling for age, race, gender, and sedentary time. Routine PA can be beneficial in helping PLWHA reduce waist circumference ultimately leading to metabolic improvements. This in turn would help PLWHA self-manage known components of MetSyn, thus reducing their risk of CVD and mortality.

Psychological correlates of HIV-related symptom distress.

This investigation sought to determine the association of symptom distress with selected psychological factors in HIV-infected persons. Data from a randomized controlled trial were used; all subjects who completed baseline data collection were included (N = 99). Data packets included these questionnaires: the Perceived Stress Scale, HIV-related Symptom Distress Scale, and Profile of Mood State. Significant correlations were included in a final regression model. The Perceived Stress Scale, total mood disturbance (including the Profile of Mood State subscales), self-rated current health, and HIV status were independently associated with both frequency of symptoms and symptom distress. Symptom frequency, depression, anger, and fatigue retained significance in the final regression model. Findings from this study indicated significant associations of multiple psychological correlates, suggesting that symptom distress is a complex outcome with a multifactorial etiology. Psychological factors such as depression, anger, and fatigue contribute to the level of distress experienced with HIV-related symptoms.

The energy balance study: the design and baseline results for a longitudinal study of energy balance.

PURPOSE: The Energy Balance Study (EBS) was a comprehensive study designed to determine over a period of 12 months the associations of caloric intake and energy expenditure on changes in body weight and composition in a population of healthy men and women. METHOD: EBS recruited men and women aged 21 to 35 years with a body mass index between 20 and 35 kg/m2. Measurements of energy intake and multiple objective measures of energy expenditure, as well as other physiological, anthropomorphic and psychosocial measurements, were made quarterly. Resting metabolic rate and blood chemistry were measured at baseline, 6 and 12 months. RESULTS: Four hundred and thirty (218 women and 212 men) completed all baseline measurements. There were statistically significant differences by sex uncovered for most anthropomorphic, physiological and behavioral variables. Only percent of kcals from fat and alcohol intake, as well as energy expenditure in light activity and very vigorous activity were not different. Self-reported weight change (mean +/- SD) over the previous year were 0.92 +/- 5.24 kg for women and--1.32 +/- 6.1 kg for men. Resting metabolic rate averages by sex were 2.88 +/- 0.35 ml/kg/min for women and 3.05 +/- 0.33 ml/kg/min for men. CONCLUSION: Results from EBS will inform our understanding of the impact of energy balance components as they relate to changes in body weight and composition. Initial findings suggest a satisfactory distribution of weight change to allow for robust statistical analyses. Resting metabolic rates well below the standard estimate suggest that the evaluation of the components of total energy expenditure will be impactful for our understanding of the roles of energy intake and expenditure on changes in energy utilization and storage.

A home-based exercise intervention to increase physical activity among people living with HIV: study design of a randomized clinical trial.

BACKGROUND: While combination antiretroviral therapy has extended the life expectancy of those infected with human immunodeficiency virus (HIV), there is a high prevalence of comorbidities that increase the risk of cardiovascular morbidity and mortality among people living with HIV/AIDS (PLWHA). The side effects associated with antiretroviral therapy (ART) lead to multiple metabolic disorders, making the management of these metabolic issues and risk of cardiovascular disease (CVD) in those treated with ART a critical issue. Clinical research trials, primarily clinical exercise, rarely include this population due to unique challenges in research methods with underserved minority populations living with a life threatening illness like HIV/AIDS. This paper describes the rationale and design of a randomized clinical trial evaluating the feasibility of a home-based exercise program designed to increase physical activity (PA) and reduce the risk of CVD in PLWHA. METHODS/DESIGN: PLWHA being treated with ART will be randomly assigned to one of two groups: a home-based PA intervention or standard care. All participants will receive an educational weight loss workbook and pedometer for self-monitoring of PA. Only those in the intervention group will receive additional elastic Thera-bands® for strength training and behavioral telephone based coaching. DISCUSSION: This study will evaluate the feasibility of a home-based program designed to increase PA among PLWHA. Further, it will evaluate the effectiveness of such a program to decrease modifiable risk factors for CVD as a secondary outcome. This study was funded by the NIH/NINR R21 Grant 1R21NRO11281. TRIAL REGISTRATION: Clinical Trial Identifier NCT01377064.

Moderate-Intensity Exercise Improves Body Composition and Improves Physiological Markers of Stress in HIV-Infected Men.

HIV/AIDS and its treatment often alter body composition and result in poorer physical functioning. The aim of this study was to determine the effects of a moderate-intensity exercise program on body composition and the hormones and cytokines associated with adverse health outcomes. HIV-infected males (N = 111) were randomized to an exercise group (EX) who completed 6 weeks of moderate-intensity exercise training, or to a nonintervention control group (CON). In pre- and postintervention, body composition was estimated via DXA, peak strength was assessed, and resting blood samples were obtained. There was a decrease in salivary cortisol at wake (P = 0.025) in the EX and a trend (P = 0.07) for a decrease 1 hour after waking. The EX had a significant increase in lean tissue mass (LTM) (P < 0.001) following the intervention. Those in the EX below median body fat (20%) increased LTM (P = 0.014) only, while those above 20% decreased fat mass (P = 0.02), total fat (N = 0.009), and trunk fat (P = 0.001), while also increasing LTM (P = 0.027). Peak strength increased between 14% and 28% on all exercises in the EX group. These data indicate that 6 weeks of moderate-intensity exercise training can decrease salivary cortisol levels, improve physical performance, and improve body composition in HIV-infected men.

Metabolic syndrome and risk of cancer mortality in men.

BACKGROUND: Metabolic syndrome (MetS) has been linked with an increased risk of developing cancer; however, the association between MetS and cancer mortality remains less clear. Little research has focused on pre-cancer risk factors that may affect the outcome of treatment. The purpose of this study was to examine the association between MetS and all-cancer mortality in men. METHODS: The participants included 33,230 men aged 20-88 years who were enrolled in the Aerobics Centre Longitudinal Study and who were free of known cancer at the baseline. RESULTS: At baseline 28% of all the participants had MetS. During an average of 14 years follow-up, there were a total of 685 deaths due to cancer. MetS at baseline was associated with a 56% greater age-adjusted risk in cancer mortality. CONCLUSION: These data show that MetS is associated with an increased risk of all-cause cancer mortality in men. Based on these findings, it is evident that successful interventions should be identified to attenuate the negative effects of MetS.

Impact of Aerobic and Resistance Exercise on the Health of HIV-Infected Persons.

Individuals infected with HIV experience numerous comorbidities caused by the disease progression and medications, lack of (or inability to perform) physical activity, malnutrition, or a combination of these causes. Common symptoms include loss of muscle mass, fatigue, lypodystrophy, lypoatrophy, and decreases in strength, functional capacity, and overall quality of life. Studies have shown that exercise is a potential treatment of many of these symptoms. Research suggests that exercise may produce beneficial physiological changes in the HIV-infected population such as improved body composition and increases in both strength and endurance. In addition, psychological conditions such as depression and anxiety have been shown to be positively affected by exercise. The purpose of this review is to examine the literature regarding effects of aerobic, resistance, and combined aerobic and resistance exercise training on HIV-infected individuals.