Repeatability of Ad Libitum Water Intake during Repeated 1 h Walking/Jogging Exercise Sessions Conducted under Hot Ambient Conditions.

A drinking strategy aiming to replace a given percentage of the sweat losses incurred during exercise should result in reproducible fluid intake volume and, hence, fluid balance from one exercise session to the other performed under similar scenarios. Whether this may also be the case with ad libitum drinking during exercise is unclear. We characterized the repeatability of ad libitum water intake during repeated 1 h exercise sessions and examined its effect over time on fluid balance and selected physiological functions and perceptual sensations. Twelve (3 women) healthy individuals participated in this study. At weekly intervals, they completed four 2 × 30 min walking/jogging exercise bouts (55% V˙O2max, 40 °C, 20-30% relative humidity) interspersed by a 3 min recovery period. During exercise, participants consumed water (20 °C) ad libitum. There were no significant differences among the four exercise sessions for absolute water intake volume (~1000 mL·h-1), percent body mass loss (~0.4%), sweat rate (~1300 mL·h-1) and percent of sweat loss replaced by water intake (~80%). Heart rate, rectal temperature, and perceived thirst and heat stress did not differ significantly between the first and fourth exercise sessions. Perceived exertion was significantly lower during the fourth vs. the first exercise session, but the difference was trivial (<1 arbitrary unit). In conclusion, ad libitum water intake during four successive identical 1 h walking/jogging sessions conducted in the heat will result in similar water intake volumes and perturbations in fluid balance, heart rate, rectal temperature, and perceived thirst, heat stress and exertion.

The Foot and Ankle in Ultramarathon Runners: Results of the Ultrarunners Longitudinal TRAcking (ULTRA) Study.

Background: The foot and ankle play a critical role in ultramarathon running. Because foot and ankle injuries are the most common location of injury in this group, proper care is essential for prevention. In this sport, small issues can become big problems over such long distances, and understanding the preventative measures taken by ultramarathon runners may provide insight for other athletes looking to avoid similar problems. The purpose of this study was to examine the routine and preventative care of the foot and ankle, as well as injury rates, in this group of high-risk athletes. Methods: The Ultrarunners Longitudinal TRAcking (ULTRA) Study is the largest known prospective longitudinal study of ultramarathon runners. In this portion of the study, participants reported general health status, running behavior and performance, as well as foot and ankle care, injuries, stretching frequency, and shoewear. Results: A total of 734 ultramarathon runners participated in the study. This group ran a median of 40.2 km per week. Overall, 71.2% of active ultramarathon runners reported a foot or ankle injury in the previous 12 months. The most common injuries reported were plantar fasciitis (36.3%), Achilles tendinitis (24.0%), nonspecific foot pain (14.0%), and stress fractures (13.4%). Sit and reach flexibility test showed that 63.7% of runners could not reach past their toes. There were no significant correlations for sit and reach flexibility or stretching frequency with injury rate. Conclusion: The high prevalence of foot and ankle injuries in ultramarathon runners does not appear to be influenced by arch type, foot strike pattern, orthotic usage, stretching behavior, or actual flexibility. A high percentage of the study runners used comfort as a shoe selection method, independent of alignment or foot strike pattern. These findings guide the clinician in shared decision making with runners about routine care, including injury prevention and shoe selection. Level of Evidence: Level II, prospective study.

Treatment with Oral Ondansetron for Ultramarathon-Associated Nausea: The TOO FUN Study.

Nausea and vomiting are common for runners during ultramarathons and often contribute to non-finishes. We aimed to determine the efficacy of ondansetron, a commonly used antiemetic, to treat nausea and vomiting in runners during an ultramarathon. Runners who had a previous history of frequent nausea or vomiting during races and entered in 160, 80, and 55 km ultramarathons in 2018 and 2019 were randomized in a double-blind fashion to 4 mg ondansetron or placebo capsules to use if they developed nausea or vomiting during the race with the ability to take three additional doses. Study participants completed a post-race online survey to assess medication use and efficacy. Of 62 study participants, 31 took either ondansetron (20) or placebo (11). In this small study, there were no group differences in those reporting any improvement in nausea and vomiting (p = 0.26) or in the amount of improvement (p = 0.15). We found no evidence that ondansetron capsules improve nausea and vomiting during ultramarathons.

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.

Programmed vs. Thirst-Driven Drinking during Prolonged Cycling in a Warm Environment.

We compared the effect of programmed (PFI) and thirst-driven (TDFI) fluid intake on prolonged cycling performance and exercise associated muscle cramps (EAMC). Eight male endurance athletes (26 ± 6 years) completed two trials consisting of 5 h of cycling at 61% V˙O2peak followed by a 20 km time-trial (TT) in a randomized crossover sequence at 30 °C, 35% relative humidity. EAMC was assessed after the TT with maximal voluntary isometric contractions of the shortened right plantar flexors. Water intake was either programmed to limit body mass loss to 1% (PFI) or consumed based on perceived thirst (TDFI). Body mass loss reached 1.5 ± 1.0% for PFI and 2.5 ± 0.9% for TDFI (p = 0.10). Power output during the 20 km TT was higher (p < 0.05) for PFI (278 ± 41 W) than TDFI (263 ± 39 W), but the total performance time, including the breaks to urinate, was similar (p = 0.48) between conditions. The prevalence of EAMC of the plantar flexors was similar between the drinking conditions. Cyclists competing in the heat for over 5 h may benefit from PFI aiming to limit body mass loss to <2% when a high intensity effort is required in the later phase of the race and when time lost for urination is not a consideration.

Proteinuria in a high-altitude 161-km (100-mile) ultramarathon.

PURPOSE: Urine dipstick analysis (UDA) is a useful tool in clinical practices. Abnormalities in UDA parameters have been observed as a result of extreme exercise. The exact incidence of UDA abnormalities, particularly proteinuria, as the result of running ultramarathons is unknown. The purpose of this study was to estimate the incidence of proteinuria and to identify the characteristics of those with proteinuria. METHODS: We conducted a prospective observational study using urine samples from volunteer athletes before and immediately after the Leadville Trail 100 Run in August 2014. There were 33 runners with both pre-race and post-race samples and a total of 70 provided post-race samples. Demographic information was collected as a part of a larger study. RESULTS: At least one abnormality was demonstrated in 89% of post-race urine samples. Twenty-one (30%) runners had post-race proteinuria (≥1+). Serum creatine kinase concentration (CK) was the only variable that was significantly correlated with the incidence of proteinuria in a multiple logistic regression model. CONCLUSION: A majority of runners developed abnormalities in their UDA. Proteinuria was common and found to be associated with serum CK concentration.

State of the Science on Ultramarathon Running After a Half Century: A Systematic Analysis and Commentary.

PURPOSE: To systematically examine scientific publishing related to ultramarathon running. METHODS: PubMed-indexed publications through 2019 were identified in which the work involved data collection at or in association with an ultramarathon running event, included experimental running trials of ultramarathon duration using human subjects, focused on human ultramarathon runners as the study participants, or were directed at discussing some aspect of ultramarathon running or ultramarathon runners. The characteristics of each publication were tabulated. RESULTS: A total of 616 indexed publications were identified, with the first being in 1970. A rapid increase in publications was seen by 2010 in association with increased participation in ultramarathon running, followed by a plateauing at around 49 annual publications from 2014 to 2018. Most (83.3%) publications were observational, and the mean annual number of 1.6 experimental studies did not change (P = .20) from 1999 to 2019. Most of the publications were related to physiological issues, and race performance was the largest topic area (21.8%). The largest percentage of publications came from authors from the United States, followed by authors from Switzerland. CONCLUSIONS: Research related to ultramarathon running has had a small presence in sport science and offers potential for further development. At present, publishing appears to be stable and without recent increased emphasis on experimental studies. Worthwhile research opportunities remain, particularly those where ultramarathons serve as a model for stress and could offer relevance to a wider population than ultramarathon runners, but such research appears challenged by relatively small participation in the activity and limited funding opportunities.

Recommendations on the Appropriate Level of Medical Support at Ultramarathons.

Participation in ultramarathons continues to grow, especially among older individuals and among younger runners who may have less running and wilderness experience than many past participants. While ultramarathons tend to have relatively few serious medical issues, adverse medical incidents do occur. These factors make it increasingly important that appropriate safety precautions and medical support are defined and implemented at these events to enhance the safety of participants, spectators, and volunteers. This document establishes the minimum recommended level of medical support that should be available at ultramarathons based on current knowledge and the experience of the authors. It offers a balance that is intended to avoid excessive stress on the local medical system while also precluding undue burden on events to provide medical support beyond that which is practical. We propose a three-level classification system to define the extent of medical services, personnel, systems, supplies, and equipment in place and recommend the level of medical support based on event size, distance/duration, remoteness, and environmental conditions that may be encountered during the event. This document also outlines the recommended education and training of medical providers and discusses other medical and logistical considerations related to the provision of medical support at ultramarathons. We suggest that ultramarathon organizers review and adopt these recommendations to enhance safety and reduce the risk of adverse events to participants.

Belief in the need for sodium supplementation during ultramarathons remains strong: findings from the Ultrarunners Longitudinal TRAcking (ULTRA) study.

In the past, ultramarathon runners have commonly believed that consuming sodium supplements, as capsules or tablets, will prevent exercise-associated hyponatremia (EAH), dehydration, muscle cramping, and nausea, but accumulating evidence indicates that sodium supplementation during ultramarathons is not necessary and may be potentially dangerous. In this work, beliefs about whether sodium supplements should be made available at ultramarathons were assessed during 2018 among 1152 participants of the Ultrarunners Longitudinal TRAcking (ULTRA) study, of which 85.2% had completed an ultramarathon during 2014-2018. Two-thirds (66.4%) of study participants indicated that sodium supplements should be made available at ultramarathons, supported by beliefs that they prevent EAH (65.5%) and muscle cramping (59.1%). Of those indicating that sodium supplements should not be made available, 85.0% indicated it is because runners can provide their own, 27.9% indicated it is because they are not necessary, and 12.1% indicated they could increase thirst drive and cause overhydration. In general, there was a tendency for those who were older, less active in running ultramarathons in recent years, and with a longer history of ultramarathon running to be less likely to know that sodium supplements do not help prevent EAH, muscle cramping, and nausea. Novelty Ultramarathon runners continue to have misunderstandings about the need for sodium supplementation during ultramarathons. Few ultramarathon runners recognize that supplementing sodium intake beyond that in food and drink is generally not necessary during ultramarathons or that it could result in overhydration. Continued educational efforts are warranted to help ensure safe participation in the sport.

Predictors of clinical success with stabilization exercise are associated with lower levels of lumbar multifidus intramuscular adipose tissue in patients with low back pain.

Purpose: Investigate the construct validity of prognostic factors purported to predict clinical success with stabilization exercise for low back pain by exploring their associations with lumbar multifidus composition.Methods: Patients with low back pain were recruited from a hospital imaging department. The presence of fivepredictors (age <40 years, positive prone instability test, aberrant trunk flexion movements, straight leg raise range of motion >91°, spinal hypermobility) were identified by standardized physical examination. Predictors were grouped by total positive findings and status on a clinical prediction rule. The proportion of lower lumbar multifidus intramuscular adipose tissue was measured with 3.0 T magnetic resonance imaging. Univariate and multivariate associations were examined with linear regression and reported with standardized beta coefficients (ß) and 95% confidence intervals.Results: Data from 62 patients (11 female) with mean (SD) age of 45.2 (11.8) years were included. Total number of predictors (ß[95% CI] = -0.37[-0.61,-0.12]; R2 = 0.12), positive prediction rule status (ß[95% CI] = -0.57[-0.79,-0.35]; R2 = 0.30), and age <40 years were associated with lower intramuscular adipose tissue (ß[95% CI] = -0.55[-0.77,-0.33]; R2 = 0.27). No other individual factors were associated with lumbar multifidus intramuscular adipose tissue.Conclusions: These findings support the construct validity of the grouped prognostic criteria. Future research should examine the clinical utility of these criteria. Implications for RehabilitationLow back pain is the single largest cause of disability worldwide and exercise therapy is recommended by international low back pain treatment guidelines.Lower levels of lumbar multifidus intramuscular adipose tissue were associated with predictors of clinical success with stabilization exercise.Higher proportions of lumbar multifidus intramuscular adipose tissue may help identify patients who require longer duration exercise training, or those who are unlikely to respond to stabilization exercise.

Participant Opinions and Expectations about Medical Services at Ultramarathons: Findings from the Ultrarunners Longitudinal TRAcking (ULTRA) Study.

Background This work explores the opinions and expectations of ultramarathon runners about medical services and their perceived quality during ultramarathons. Methods Focused questions related to medical services at ultramarathons were included in the 2018 survey of Ultrarunners Longitudinal TRAcking (ULTRA) Study enrollees. Results Among the 1,156 respondents, 83.2% agreed that ultramarathons should provide at least a minimum level of medical support with basic first aid and emergency transport services rated as the most important medical services, and individuals with basic first aid training rated as the most important medical providers at ultramarathons. Participant safety was felt to largely be the responsibility of each runner as well as the race and/or medical director. Among 832 respondents having completed an ultramarathon in 2016-2018, their impression of medical services at 4,853 ultramarathons was generally favorable. Of the four percent of times in which medical support was needed, it met expectations 74% of the time. Of the total of 240 different medical issues for which medical support was needed, blister management was the most common, accounting for 26.7% of issues. Conclusions Even though medical services receive minimal utilization during ultramarathons, ultramarathon runners largely believe that these events should provide at least a minimum level of medical support. Ultramarathon runners place a high onus for safety during ultramarathons on themselves, but they also place a high level of responsibility on race and medical directors, so it is prudent for the race and medical directors to consider this information and avoid a mismatch between runner expectations and the medical services actually provided.

Too much too early? An analysis of worldwide childhood ultramarathon participation and attrition in adulthood.

BACKGROUND: Physical inactivity is associated with chronic disease and premature death, but excessive exercise can also lead to injury. Ultramarathon running is popular among adults but has not been assessed in children. To analyze ultramarathon participation in children and to determine if they continue running ultramarathons into adulthood provide some evidence of associated health risks. METHODS: Race results databases were used to identify ultramarathon finishers under the age of 19 between 1960-2017. Participation trends across calendar years, age groups and different race distances were analyzed and continued participation into adulthood examined. RESULTS: A total of 7775 finishes by 5418 individual children were recorded worldwide with an increase in ultramarathon finishers over time (P<0.0001), with the greatest number among older age groups (>16 years) and the 50 and 100 km race distances. Less than 25% of childhood ultramarathon runners continued running ultramarathons into adulthood and approximately 12% continued beyond 20 years. CONCLUSIONS: Childhood participants has been growing exponentially over the last 20 years. While few of those children continue to complete ultramarathons into adulthood, the finding that some have continued well into adulthood suggests there is no obligate serious adverse physical impairment resulting from childhood ultramarathon participation.

Nutrition for Ultramarathon Running: Trail, Track, and Road.

Ultramarathon running events and participation numbers have increased progressively over the past three decades. Besides the exertion of prolonged running with or without a loaded pack, such events are often associated with challenging topography, environmental conditions, acute transient lifestyle discomforts, and/or event-related health complications. These factors create a scenario for greater nutritional needs, while predisposing ultramarathon runners to multiple nutritional intake barriers. The current review aims to explore the physiological and nutritional demands of ultramarathon running and provide general guidance on nutritional requirements for ultramarathon training and competition, including aspects of race nutrition logistics. Research outcomes suggest that daily dietary carbohydrates (up to 12 g·kg-1·day-1) and multiple-transportable carbohydrate intake (∼90 g·hr-1 for running distances ≥3 hr) during exercise support endurance training adaptations and enhance real-time endurance performance. Whether these intake rates are tolerable during ultramarathon competition is questionable from a practical and gastrointestinal perspective. Dietary protocols, such as glycogen manipulation or low-carbohydrate high-fat diets, are currently popular among ultramarathon runners. Despite the latter dietary manipulation showing increased total fat oxidation rates during submaximal exercise, the role in enhancing ultramarathon running performance is currently not supported. Ultramarathon runners may develop varying degrees of both hypohydration and hyperhydration (with accompanying exercise-associated hyponatremia), dependent on event duration, and environmental conditions. To avoid these two extremes, euhydration can generally be maintained through "drinking to thirst." A well practiced and individualized nutrition strategy is required to optimize training and competition performance in ultramarathon running events, whether they are single stage or multistage.

Proper Hydration During Ultra-endurance Activities.

The health and performance of ultra-endurance athletes is dependent on avoidance of performance limiting hypohydration while also avoiding the potentially fatal consequences of exercise-associated hyponatremia due to overhydration. In this work, key factors related to maintaining proper hydration during ultra-endurance activities are discussed. In general, proper hydration need not be complicated and has been well demonstrated to be achieved by simply drinking to thirst and consuming a typical race diet during ultra-endurance events without need for supplemental sodium. As body mass is lost from oxidation of stored fuel, and water supporting the intravascular volume is generated from endogenous fuel oxidation and released with glycogen oxidation, the commonly promoted hydration guidelines of avoiding body mass losses of >2% can result in overhydration during ultra-endurance activities. Thus, some body mass loss should occur during prolonged exercise, and appropriate hydration can be maintained by drinking to the dictates of thirst.

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.

Considerations for ultra-endurance activities: part 1- nutrition.

Ultra-endurance activities (≥ 4h) present unique challenges that, beyond fatigue, may be exacerbated by sub-optimal nutrition during periods of increased requirements and compromised gastrointestinal function. The causes of fatigue during ultra-endurance exercise are multi-factorial. However, mechanisms can potentially include central or peripheral fatigue, thermal stress, dehydration, and/or endogenous glycogen store depletion; of which optimising nutrition and hydration can partially attenuate. If exercise duration is long enough (e.g. ≥ 10h) and exercise intensity low enough (e.g. 45-60% of maximal oxygen uptake), it is bio-energetically plausible that ketogenic adaptation may enhance ultra-endurance performance, but this requires scientific substantiation. Conversely, the scientific literature has consistently demonstrated that daily dietary carbohydrates (3-12g/kg/day) and carbohydrate intake (30-110g/h) during ultra-endurance events can enhance performance at individually tolerable intake rates. Considering gastrointestinal symptoms are common in ultra-endurance activities, effective dietary prevention and management strategies may provide functional, histological, systemic, and symptomatic benefits. Taken together, a well-practiced and individualized fuelling approach is required to optimize performance in ultra-endurance events.

Considerations for ultra-endurance activities: part 2 - hydration.

It is not unusual for those participating in ultra-endurance (> 4 hr) events to develop varying degrees of either hypohydration or hyperhydration. Yet, it is important for ultra-endurance athletes to avoid the performance limiting and potentially fatal consequences of these conditions. During short periods of exercise (< 1 hr), trivial effects on the relationship between body mass change and hydration status result from body mass loss due to oxidation of endogenous fuel stores, and water supporting the intravascular volume being generated from endogenous fuel oxidation and released with glycogen oxidation. However, these effects have meaningful implications during prolonged exercise. In fact, body mass loses well over 2% may be required during some ultra-endurance activities to avoid hyperhydration. Therefore, the typical hydration guidelines to avoid more than 2% body mass loss do not apply in ultra-endurance activities and can potentially result in hyperhydration. Fortunately, achieving the balance of proper hydration during ultra-endurance activities need not be complicated and has been well demonstrated to generally be achieved by simply drinking to thirst and avoiding excessive sodium supplementation with intention of replacing all sodium losses during the exercise.