Cardiovascular risk among ultra-endurance runners.

BACKGROUND: Our objective was to determine the prevalence and clinical correlates of conventional cardiovascular risk factors among ultra-endurance marathon runners. METHODS: An electronic internet survey to characterize modifiable cardiovascular risk factors including diabetes, hypertension, dyslipidemia, tobacco exposure and obesity (BMI>30) among competitive ultra-endurance runners. RESULTS: Among 290 respondents (mean±SD, 42±11 years, 31.4% female), 106 (36.6%) had at least one established cardiovascular risk factor. Female sex, younger age and participation in competitive high school or collegiate sports were associated with freedom from cardiovascular risk factors. There were no significant associations between risk factor status and either hours per week of running training (risk factor negative: 10±7 vs. risk factor positive: 11±8 hours, P=0.42) or years of ultra-endurance competition (6±8 vs. 7±9 years, P=0.38). Runners with at least one cardiovascular risk factor were more likely to have had personal or peer concerns about excessive alcohol use. CONCLUSIONS: Conventional cardiovascular risk factors are common among ultra-endurance runners. Early-life participation in competitive sports, rather than adult exercise habits, is associated with freedom from the development of cardiovascular risk factors during middle age. Determining mechanistic explanations for the legacy effect of early life exercise as a means to reduce cardiovascular risk among aging athletes represents an important area of future work.

Impact of Ad Libitum Versus Programmed Drinking on Endurance Performance: A Systematic Review with Meta-Analysis.

BACKGROUND: Debate continues on how athletes should hydrate during exercise. Several studies have recently been published comparing the effect of ad libitum (ALD) and programmed drinking (PD) on endurance performance (EP). OBJECTIVE: This work examined whether one drinking strategy offers an EP advantage over the other. DESIGN: Systematic review and meta-analysis of crossover controlled trials. DATA SOURCES: PubMed and SPORTDiscus database searches. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Key criteria were (1) experiments performed under controlled settings; (2) exercise lasting ≥ 1 h; (3) exercise initiated in an euhydrated state; (4) fluid intake during PD > ALD; (5) fluid composition matched for electrolytes; and (6) carbohydrate intake varied by > 25% between conditions when the exercise was 1 h and matched for exercise > 1 h. RESULTS: Seven publications, producing eight effect estimates, including cycling and running exercises and representing 82 subjects, were included. Mean (± standard deviation) ambient temperature, exercise intensity and duration of the experiments were 28 ± 6 °C, 81 ± 12% of maximal heart rate and 96 ± 25 min, respectively. Mean rate of fluid consumption for the PD and ALD conditions was 1073 ± 247 mL/h and 505 ± 156 mL/h, respectively. Mean change in body mass for the PD and ALD conditions was - 1.0 ± 0.5% and - 2.1 ± 0.7%, respectively. Compared with PD, ALD improved EP by 0.98 ± 0.44% (95% confidence interval 0.11-1.84%). The greater EP conferred by ALD is likely trivial. CONCLUSIONS: Despite ALD being associated with an hourly rate of fluid consumption half as much as PD, and resulting in a dehydration level considered sufficient to impair EP, both strategies were found to similarly impact 1-2 h cycling or running performances conducted at moderate to high intensity and under temperate to warm ambient conditions.

Nausea is associated with endotoxemia during a 161-km ultramarathon.

This study explored possible contributing factors to gastrointestinal distress, including endotoxemia, hyperthermia, dehydration and nutrition, during a 161-km ultramarathon. Thirty runners participated in the study and 20 finished the race. At three checkpoints and the finish, runners were interviewed to assess the incidence and severity of 12 gastrointestinal symptoms and to determine dietary intake. Core temperature was measured at the same locations. Runners were weighed pre-race, at the three checkpoints and the finish to monitor hydration status. Blood markers for endotoxemia (sCD14) and inflammation (interleukin-6 and C-reactive protein) were measured pre- and post-race. Gastrointestinal symptoms were experienced by most runners (80%), with nausea being the most common complaint (60%). Runners with nausea experienced significantly greater (P = 0.02) endotoxemia than those without nausea (sCD14 mean increase 0.7 versus 0.5 µg · mL(-1)). There was a significant positive correlation (r = 0.652, P = 0.005) between nausea severity and endotoxemia level. Inflammatory response, core temperature, hydration level and race diet were similar between runners with and without nausea. This study links endotoxemia to nausea in ultramarathon runners. Other possible contributing factors to nausea such as hyperthermia, dehydration and nutrition did not appear to play a role in the symptomatic runners in this study.

Special Considerations in Medical Screening for Participants in Remote Endurance Events.

As participation at remote endurance events increases, so does the need to screen participants for potentially problematic medical conditions, but this process has been ill-defined to date. This article aims to outline a general approach to screening and discusses common or important medical conditions that may need consideration in the screening process. Medical conditions that are considered low risk may translate to high-risk conditions in the setting of a remote and austere location. Medical directors of remote endurance events should have a familiarity with assessing risks and applying informed consent principles to participation. While there are no specific standards on medical disqualification from an event based on medical history alone, several systematic considerations should be made that allow for an assessment of risk to an individual for a specific event. The medical director and event director, in discussion with the athlete and treating clinician when appropriate, should come to a consensus on participation when high-risk medical conditions become apparent during the screening process. Both modifications and accommodations to participation may be used to mitigate both clinical and medicolegal risk and allow for participation.

An investigation of ultramarathon-associated visual impairment.

OBJECTIVE: The purpose of this study was to investigate the characteristics under which ultramarathon-associated visual impairment occurs and to seek to identify its physiological basis and risk factors. METHODS: Through an online questionnaire, distributed worldwide, we obtained information from 173 self-identified ultramarathon runners who had experienced visual impairment during an ultramarathon. We attempted to characterize this vision impairment-its symptoms, duration, and the conditions under which it occurs. Select characteristics were compared with a reference group of 412 registrants of the 161-km Western States Endurance Run. RESULTS: Ultramarathon-associated visual impairment was typically characterized as painless clouding of vision that resolved either during (13.5%) or after racing within a median of 3.5 hours (range 0 to 48 hours) upon cessation of running. The mean (±SD) distance at which vision impairment occurred was 73±40 km, and the 161-km distance was the most frequent race distance (46.8%) in which visual impairment occurred. Visual impairment was often recurrent, with respondents reporting having it develop during a median of 2 races. Respondents with a history of refractive surgery had more episodes than those without such history (median 3.5 vs 2 episodes, P=.010). Compared with the reference group, runners with visual impairment were nearly twice as likely (23.7% vs 12.1%, P<.001) to have had refractive surgery. CONCLUSIONS: Ultramarathon-associated visual impairment typically presents as a painless clouding of vision that is self-limited but tends to recur in certain runners. Risk appears higher among those with a history of refractive surgery, which is relevant for ultramarathon runners who are considering, or who have a history of, refractive surgery.

The impact of chronic endurance and resistance training upon the right ventricular phenotype in male athletes.

OBJECTIVES: The traditional view of differential left ventricular adaptation to training type has been questioned. Right ventricular (RV) data in athletes are emerging but whether training type mediates this is not clear. The primary aim of this study was to evaluate the RV phenotype in endurance- vs. resistance-trained male athletes. Secondary aims included comparison of RV function in all groups using myocardial speckle tracking, and the impact of allometric scaling on RV data interpretation. METHODS: A prospective cross-sectional design assessed RV structure and function in 19 endurance-trained (ET), 21 resistance-trained (RT) and 21 sedentary control subjects (CT). Standard 2D tissue Doppler imaging and speckle tracking echocardiography assessed RV structure and function. Indexing of RV structural parameters to body surface area (BSA) was undertaken using allometric scaling. RESULTS: A higher absolute RV diastolic area was observed in ET (mean ± SD: 27 ± 4 cm(2)) compared to CT (22 ± 4 cm(2); P < 0.05) that was maintained after scaling. Whilst absolute RV longitudinal dimension was greater in ET (88 ± 9 mm) than CT (81 ± 10 mm; P < 0.05), this difference was removed after scaling. Wall thickness was not different between ET and RT and there were no between group differences in global or regional RV function. CONCLUSION: We present some evidence of RV adaptation to chronic ET in male athletes but limited structural characteristics of an athletic heart were observed in RT. Global and regional RV functions were comparable between groups. Allometric scaling altered data interpretation in some variables.

The impact of an ultramarathon on hormonal and biochemical parameters in men.

OBJECTIVE: To examine circulating hormonal responses in men competing in the Western States Endurance Run (WSER, June 23 to 24, 2012): a 161-km trail run that starts in Squaw Valley, CA, and concludes in Auburn, CA. METHODS: We examined 12 men who completed the WSER. Blood samples were obtained the morning before the race, immediately postrace (IP), and 1 (D1) and 2 (D2) days after the conclusion of the WSER. The hypothalamic-pituitary-testicular (HPT) axis was assessed by measuring testosterone and luteinizing hormone (LH). We also examined sex hormone-binding globulin (SHBG) and cortisol. Biochemical and muscle damage markers were also measured. RESULTS: Relative to prerace, there were significant (P ≤ .05) decreases in testosterone, LH, and SHBG, whereas cortisol showed a significantly marked elevation at IP. Testosterone, LH, SHBG, and cortisol remained significantly different from prerace at D1. Additionally, the testosterone to cortisol (T:C) ratio, a marker of anabolism, was decreased at IP and D1. Serum total protein, albumin, and globulin significantly decreased at IP, and remained decreased at D1 and D2. Bilirubin increased significantly IP and D1, whereas alkaline phosphatase decreased at D1 and D2. Creatine kinase, myoglobin, aspartate aminotransferase, and alanine aminotransferase increased at IP, and continued to be significantly elevated at D1 and D2. CONCLUSIONS: Training for and completing the WSER produced a significant suppression in the HPT axis as seen by decreased levels of testosterone and LH. Additionally, running the WSER continued to influence endocrine function until 2 days after the race. Furthermore, the stress caused by the WSER produced severe muscle damage.

Body mass index and its correlates in 1,212 ultramarathon runners: baseline findings from the ULTRA study.

BACKGROUND: Little is known about the sociodemographics and lifestyle behaviors of ultramarathon runners, and the effects of these characteristics on body weight and body mass index (BMI). METHODS: We cross-sectionally analyzed baseline data of 1212 ultramarathoners on sociodemographics, lifestyle behaviors and BMI from the initial 12-month enrollment period in a longitudinal observational study. RESULTS: The ultramarathoners were mostly middle-aged men who were more educated, more likely to be in a stable relationship, and more likely to use over-the-counter vitamins/supplements than the general population. They appear to gain less body weight with advancing age than the general population. Factors with the greatest effect on current BMI were BMI at 25 years of age and sex, which explained 48% and 3% of the variance. Negligible, but statistically significant direct relationships, with BMI were observed for age, work hours per week, television watching hours per week, and composite fat consumption frequency score. Negligible, but statistically significant inverse relationships, with BMI were observed for running distance during the prior year, and composite fruit and vegetable consumption frequency score. CONCLUSIONS: While lifestyle decisions were found to impact BMI within this group of ultramarathoners, BMI at age 25 was the strongest predictor of current BMI.

Health and exercise-related medical issues among 1,212 ultramarathon runners: baseline findings from the Ultrarunners Longitudinal TRAcking (ULTRA) Study.

Regular exercise is associated with substantial health benefits; however, little is known about the health impact of extreme levels of exercise. This study examined the prevalence of chronic diseases, health-care utilization, and risk factors for exercise-related injuries among ultramarathon runners. Retrospective, self-reported enrollment data from an ongoing longitudinal observational study of 1,212 active ultramarathon runners were analyzed. The most prevalent chronic medical conditions were allergies/hay fever (25.1%) and exercise-induced asthma (13.0%), but there was a low prevalence of serious medical issues including cancers (4.5%), coronary artery disease (0.7%), seizure disorders (0.7%), diabetes (0.7%), and human immunodeficiency virus (HIV) infection (0.2%). In the year preceding enrollment, most (64.6%) reported an exercise-related injury that resulted in lost training days (median of 14 days), but little nonattendance of work or school due to illness, injury, or exercise-related medical conditions (medians of 0 days for each). The knee was the most common area of exercise-related injury. Prior year incidence of stress fractures was 5.5% with most (44.5%) involving the foot. Ultramarathon runners who sustained exercise-related injuries were younger (p<0.001) and less experienced (p<0.01) than those without injury. Stress fractures were more common (p<0.01) among women than men. We conclude that, compared with the general population, ultramarathon runners appear healthier and report fewer missed work or school days due to illness or injury. Ultramarathon runners have a higher prevalence of asthma and allergies than the general population, and the prevalence of serious medical issues was nontrivial and should be recognized by those providing medical care to these individuals. Ultramarathon runners, compared with shorter distance runners, have a similar annual incidence of exercise-related injuries but higher proportion of stress fractures involving the foot, and it is the younger and less experienced ultramarathoners who appear most at risk for injury.

The need for salt: does a relationship exist between cystic fibrosis and exercise-associated hyponatremia?

Salt replacement is often recommended to prevent exercise-associated hyponatremia (EAH) despite a lack of evidence to support such practice. Exercise-associated hyponatremia is known to be a complex process resulting from the interplay of hydration, arginine vasopressin, and sodium balance. Although evidence suggests overhydration is the dominant pathophysiologic factor in most cases, the contributions of sweat sodium losses remain unclear. A theoretical genetic mechanism producing exuberant sweat sodium loss in athletes is the presence of cystic fibrosis (CF) gene. Individuals with CF develop hypovolemic hyponatremia by sodium loss via sweat through a defective chloride ion transport channel, the CF transmembrane conductance regulator (CFTR). Elevated sweat sodium concentrations in CF single heterozygotes suggest that athletes developing EAH may be CFTR carriers. We targeted the 2010 and 2011 Western States Endurance Run ultramarathon, an event where athletes with EAH regularly present in a hypovolemic state, for a cohort maximizing the potential to document such a relationship. A total of 798 runners started the 2010 (n = 423) and 2011 (n = 375) races. Of the 638 finishers, 373 were screened for EAH by blood draw, 60 (16%) were found to have EAH, and 31 (alpha = 0.05 for n = 9) reported their CF result from a saliva-based genetic testing kit. Neither the 31 EAH-positive athletes nor the 25 EAH-negative comparison cohort athletes tested positive for a CF mutation. This null relationship suggests that CFTR mutations are not associated with the development of EAH and that salt supplementation is unnecessary for such a reason.