Does Prophylactic Stretching Reduce the Occurrence of Exercise-Associated Muscle Cramping? A Critically Appraised Topic.

CLINICAL SCENARIO: Exercise-associated muscle cramps (EAMC) are sudden, painful, and involuntary contractions of skeletal muscles during or after physical activity. The best treatment for EAMC is gentle static stretching until abatement. Stretching is theorized to relieve EAMC by normalizing alpha motor neuron control, specifically by increasing Golgi tendon organ activity, and physically separating contractile proteins. However, it is unclear if stretching or flexibility training prevents EAMC via the same mechanisms. Despite this, many clinicians believe prophylactic stretching prevents EAMC occurrence. CLINICAL QUESTION: Do athletes who experience EAMC during athletic activities perform less prophylactic stretching or flexibility training than athletes who do not develop EAMC during competitions? SUMMARY OF KEY FINDINGS: In 3 cohort studies and 1 case-control study, greater preevent muscle flexibility, stretching, or flexibility training (ie, duration, frequency) was not predictive of who developed EAMC during competition. In one study, athletes who developed EAMC actually stretched more often and 9 times longer (9.8 [23.8] min/wk) than noncrampers (1.1 [2.5] min/wk). CLINICAL BOTTOM LINE: There is minimal evidence that the frequency or duration of prophylactic stretching or flexibility training predicts which athletes developed EAMC during competition. To more effectively prevent EAMC, clinicians should identify athletes' unique intrinsic and extrinsic risk factors and target those risk factors with interventions. STRENGTH OF RECOMMENDATION: Minimal evidence from 3 prospective cohort studies and 1 case-control study (mostly level 3 studies) that suggests prophylactic stretching or flexibility training can predict which athletes develop EAMC during athletic competitions.

Comparative study of therapy-related and de novo adult b-cell acute lymphoblastic leukaemia.

We report a comparative analysis of patients with therapy-related acute lymphoblastic leukaemia (tr-ALL) vs de novo ALL. We identified 331 patients with B-ALL; 69 (21%) were classified as tr-ALL. The most common prior malignancies were breast (23·2%) and plasma cell disorders (20·3%). Patients with tr-ALL were older (median 63·2 vs. 46·2 years, P < 0.001), more often female (66·7% vs. 43·5%, P < 0·001), and more likely to have hypodiploid cytogenetics (18·8% vs. 5·0%, P < 0·001). In multivariable analysis, patients with tr-ALL were less likely to achieve complete remission [odds ratio (OR) = 0·16, P < 0·001] and more likely to be minimal residual disease-positive (OR = 4·86, P = 0·01) but had similar OS after diagnosis and allo-haematopoietic cell transplantation.

Sweat Characteristics in Individuals With Varying Susceptibilities of Exercise-Associated Muscle Cramps.

ABSTRACT: Szymanski, M, Miller, KC, O'Connor, P, Hildebrandt, L, and Umberger, L. Sweat characteristics in individuals with varying susceptibilities of exercise-associated muscle cramps. J Strength Cond Res 36(5): 1171-1176, 2022-Many medical professionals believe dehydration and electrolyte losses cause exercise-associated muscle cramping (EAMC). Unlike prior field studies, we compared sweat characteristics in crampers and noncrampers but accounted for numerous factors that affect sweat characteristics including initial hydration status, diet and fluid intake, exercise conditions, and environmental conditions. Sixteen women and 14 men (mean ± SD; age = 21 ± 2 year, body mass = 69.1 ± 11.6 kg, height = 171.4 ± 9.9 cm) self-reported either no EAMC history (n = 8), low EAMC history (n = 10), or high EAMC history (n = 12). We measured V̇o2max, and subjects recorded their diet. At least 3 days later, subjects ran at 70% of their V̇o2max for 30 minutes in the heat (39.9 ± 0.6° C, 36 ± 2% relative humidity). Dorsal forearm sweat was collected and analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). Sweat rate (SWR) was estimated from body mass and normalized using body surface area (BSA). Dietary fluid, Na+, and K+ ingestion was estimated from a 3-day diet log. We observed no differences for any variable among the original 3 groups (p = 0.05-p = 0.73). Thus, we combined the high and low cramp groups and reanalyzed the data against the noncramping group. Again, there were no differences for [Na+]sw (p = 0.68), [K+]sw (p = 0.86), [Cl-]sw, (p = 0.69), SWR/BSA (p = 0.11), dietary Na+ (p = 0.14), dietary K+ (p = 0.66), and fluid intake (p = 0.28). Fluid and electrolyte losses may play a more minor role in EAMC genesis than previously thought.

Molecular-Driven Therapy in Advanced Thyroid Cancer.

OPINION STATEMENT: With a growing understanding of the biologic drivers of different thyroid cancers, there is an ongoing revolution in the treatment of aggressive and advanced disease variants. This includes matching patients with specific point mutations or gene fusions to targeted therapies (e.g., selective RET inhibitors), delineating patients who are likely to respond to immune checkpoint inhibition (i.e., PD-L1-positive tumors) and even priming responses to traditional therapies such as radioactive iodine (via concomitant MAPK pathway inhibition). There is also a growing role for genomics in the prognostication of thyroid tumors to aid the adjudication of appropriate treatments. Taking stock of the current state of the field, recent successes should be celebrated, but there still remains a long road ahead to improve outcomes for patients, particularly for radioactive-iodine refractory differentiated thyroid cancer and anaplastic thyroid cancer. In this review, we summarize findings from recent clinical trials and highlight promising preclinical data supporting molecular-driven therapy in advanced thyroid cancer. Ultimately, enrollment in clinical trials remains paramount to the advancement of thyroid cancer care.

Sweat Characteristics of Cramp-Prone and Cramp-Resistant Athletes.

Exercise-associated muscle cramps (EAMCs) are thought to be caused by dehydration and/or electrolyte losses. In this multicenter, cross-sectional study, the authors determined whether sweat rates (SRs), sweat electrolyte concentrations, or sweat electrolyte content differed in athletes with (i.e., crampers) and without (i.e., noncrampers) a history of EAMCs and whether these variables could predict EAMC-prone athletes. Male and female collegiate athletes (N = 350) from 11 sports with (n = 245) and without (n = 105) a self-reported history of EAMCs completed a typical exercise or conditioning session. SRs, calculated from body mass, and posterior forearm sweat were analyzed for sweat sodium concentration ([Na+]sw), sweat potassium concentration ([K+]sw), and sweat chloride concentration ([Cl-]sw). The authors used SRs and sweat electrolyte concentrations to calculate sweat electrolyte content lost. Within each gender, no differences in SRs (204 males, p = .92; 146 females, p = .24); [Na+]sw (191 males, p = .55; 126 females, p = .55); Na+sw content (191 males, p = .59; 126 females, p = .20); [K+]sw (192 males, p = .57; 126 females, p = .87); K+sw content (192 males, p = .49; 126 females, p = .03); [Cl-]sw (192 males, p = .94; 77 females, p = .57); and Cl-sw content (192 males, p = .55; 77 females, p = .34) occurred between crampers and noncrampers. Receiver operating characteristic curve analysis revealed that sweat electrolyte content and SRs were predictive of EAMC-prone athletes in American football (area under curve = 0.65-0.72, p ≤ .005), but not in any other sport. EAMCs may not be solely caused by fluid or electrolyte losses in most athletes. Fluid and electrolyte replacement may help American footballers. Clinicians should individualize fluid and electrolyte replacement and understand different etiologies for EAMCs.

Histone deacetylase inhibition in combination with MEK or BCL-2 inhibition in multiple myeloma.

Despite recent advances in the treatment of multiple myeloma, patients with this disease still inevitably relapse and become refractory to existing therapies. Mutations in K-RAS, N-RAS and B-RAF are common in multiple myeloma, affecting 50% of patients at diagnosis and >70% at relapse. However, targeting mutated RAS/RAF via MEK inhibition is merely cytostatic in myeloma and largely ineffective in the clinic. We examined mechanisms mediating this resistance and identified histone deacetylase inhibitors as potent synergistic partners. Combining the MEK inhibitor AZD6244 (selumetinib) with the pan-histone deacetylase inhibitor LBH589 (panobinostat) induced synergistic apoptosis in RAS/RAF mutated multiple myeloma cell lines. Interestingly, this synergy was dependent on the pro-apoptotic protein BIM. We determined that while single-agent MEK inhibition increased BIM levels, the protein remained sequestered by antiapoptotic BCL-2 family members. LBH589 dissociated BIM from MCL-1 and BCL-XL, which allowed it to bind BAX/BAK and thereby initiate apoptosis. The AZD6244/LBH589 combination was specifically active in cell lines with more BIM:MCL-1 complexes at baseline; resistant cell lines had more BIM:BCL-2 complexes. Those resistant cell lines were synergistically killed by combining the BH3 mimetic ABT-199 (venetoclax) with LBH589. Using more specific histone deacetylase inhibitors, i.e. MS275 (entinostat) and FK228 (romidepsin), and genetic methods, we determined that concomitant inhibition of histone deacetylases 1 and 2 was sufficient to synergize with either MEK or BCL-2 inhibition. Furthermore, these drug combinations effectively killed plasma cells from myeloma patients ex vivo Given the preponderance of RAS/RAF mutations, and the fact that ABT-199 has demonstrated clinical efficacy in relapsed/refractory multiple myeloma, these drug combinations hold prom ise as biomarker-driven therapies.

Precooling's Effect on American Football Skills.

Bradley, LJ, Miller, KC, Wiese, BW, and Novak, JR. Precooling's effect on American football skills. J Strength Cond Res 33(10): 2616-2621, 2019-Precooling (i.e., cooling before exercise) may reduce the risk of exertional heatstroke (EHS) in American football athletes. However, implementation of precooling by coaches or medical staff would likely be poor if it impaired performance. We investigated whether precooling impacted American football skill performance in this randomized, crossover, counterbalanced study. Twelve men (24 ± 2 years, mass = 85.5 ± 6.3 kg, height = 181.8 ± 8.1 cm) completed a familiarization day to practice each skill and then 2 testing days. On testing days (wet-bulb globe temperature = 19.3 ± 4.1° C), subjects were either precooled for 15 minutes using cold-water immersion (10.1 ± 0.3° C) or not (control). Then, they donned an American football uniform and completed several bouts of 8 different football skills. Rectal temperature (Trec) was measured before, during, and after skill testing. Precooling did not affect vertical jump, broad jump, agility, dynamic or stationary catching, or maximum throwing distance (p ≥ 0.13). Precooling impaired 40-yard dash time (precooling = 5.72 ± 0.53 seconds, control = 5.31 ± 0.34 seconds; p = 0.03, effect size = 1.2) and throwing accuracy (precooling = 4 ± 1 points, control = 7 ± 2 points; p = 0.001, effect size = 1.4). On average, Trec was 0.58 ± 0.35° C lower during skills testing after precooling and statistically differed from control from minute 10 to the end of testing (∼35 minutes; p < 0.05, effect size ≥ 1.2). Precooling may be a useful EHS prevention strategy in American football players because it lowered Trec without impacting most skills. By lowering Trec, precooling would prolong the time it would take for an athlete's Trec to become dangerous (i.e., >40.5° C). If precooling is implemented, coaches should alter practice so that throwing accuracy and speed drills occur after an athlete's Trec returns to normal (i.e., >35 minutes).

Does Precooling With Whole-Body Immersion Affect Thermal Sensation or Perceived Exertion? A Critically Appraised Topic.

Clinical Scenario: Exertional heat stroke (EHS) is a potentially deadly heat illness and poses a significant health risk to athletes; EHS survival rates are near 100% if properly recognized and treated. Whole-body cold water immersion (CWI) is the most effective method for lowering body core temperature. Precooling (PC) with CWI before exercise may prevent severe hyperthermia or EHS by increasing the body's overall heat storage capacity. However, PC may also alter athletes' perception of how hot they feel or how hard they are exercising. Consequently, they may be unable to accurately perceive their body core temperature or how hard they are working, which may predispose them to severe hyperthermia or EHS. Clinical Question: Does PC with whole-body CWI affect thermal sensation (TS) or rating of perceived exertion (RPE) during exercise in the heat? Summary of Key Findings: In 4 studies, RPE during exercise ranged from 12 (2.0) to 20 (3.0), with no clinically meaningful differences between PC and control trials. TS scores ranged from 2 (1.0) to 8 (0.5) in control trials and from 2 (1.0) to 7.5 (0.5) during PC trials. Clinical Bottom Line: PC did not cause clinically meaningful differences in RPE or TS during exercise. It is unlikely that PC would predispose athletes to EHS by altering perceptions of exercise intensity or body core temperature. Strength of Recommendation: None of the reviewed studies (all level-2 studies with Physiotherapy Evidence Database scores ≥ 5) suggest that PC with CWI influences RPE or TS in exercising males.

Does Gender Affect Rectal Temperature Cooling Rates? A Critically Appraised Topic.

Clinical Scenario: Exertional heat stroke (EHS) is a medical emergency characterized by body core temperatures >40.5°C and central nervous system dysfunction. An EHS diagnosis should be immediately followed by cold-water immersion (CWI). Ideally, EHS victims cool at a rate >0.15°C/min until their temperature reaches 38.9°C. While generally accepted, these EHS treatment recommendations often stem from research that examined only males. Since gender differences exist in anthropomorphics (eg, body surface area, lean body mass) and anthropomorphics impact CWI cooling rates, it is possible that CWI cooling rates may differ between genders. Clinical Question: Do CWI rectal temperature (Trec) cooling rates differ between hyperthermic males and females? Summary of Findings: The average Trec cooling rate across all examined studies for males and females was 0.18 (0.05) and 0.24 (0.03)°C/min, respectively. Hyperthermic females cooled ∼33% faster than males. Clinical Bottom Line: Hyperthermic females cooled faster than males, most likely because of higher body surface area to mass ratios and less lean body mass. Regardless of gender, CWI is highly effective at lowering Trec. Clinicians must be able to treat all EHS victims, regardless of gender, with CWI, given its high survival rate when implemented appropriately. Strength of Recommendation: Moderate evidence (2 level 3 studies) suggests that females cool faster than males when treated with CWI following severe hyperthermia. Despite gender differences, cooling rates exceeded cooling rate recommendations for EHS victims (ie, 0.15°C/min).

Prophylactic stretching does not reduce cramp susceptibility.

INTRODUCTION: Some clinicians advocate stretching to prevent muscle cramps. It is unknown whether static or proprioceptive neuromuscular facilitation (PNF) stretching increases cramp threshold frequency (TFc ), a quantitative measure of cramp susceptibility. METHODS: Fifteen individuals completed this randomized, counterbalanced, cross-over study. We measured passive hallux range of motion (ROM) and then performed 3 minutes of either static stretching, PNF stretching (hold-relax-with agonist contraction), or no stretching. ROM was reassessed and TFc was measured. RESULTS: PNF stretching increased hallux extension (pre-PNF 81 ± 11°, post-PNF 90 ± 10°; P < 0.05) but not hallux flexion (pre-PNF 40 ± 7°, post-PNF 40 ± 7°; P > 0.05). Static stretching increased hallux extension (pre-static 80 ± 11°, post-static 88 ± 9°; P < 0.05) but not hallux flexion (pre-static 38 ± 9°, post-static 39 ± 8°; P > 0.05). No ROM changes occurred with no stretching (P > 0.05). TFc was unaffected by stretching (no stretching 18 ± 7 Hz, PNF 16 ± 4 Hz, static 16 ± 5 Hz; P = 0.37). DISCUSSION: Static and PNF stretching increased hallux extension, but neither increased TFc . Acute stretching may not prevent muscle cramping. Muscle Nerve 57: 473-477, 2018.

Muscle cramp susceptibility increases following a volitionally induced muscle cramp.

INTRODUCTION: Muscle cramping may increase peripheral nervous system excitability. It is unknown if, and how long, cramp susceptibility is affected by previous cramping. We tested whether volitionally induced muscle cramps (VIMCs) lowered cramp threshold frequency (TFc ) and how long TFc was affected post-VIMC. METHODS: Fifteen cramp-prone participants volitionally induced a flexor hallucis brevis (FHB) cramp on 4 separate days. FHB TFc was measured before VIMC (i.e., baseline) and 5, 30, and 60 min post-VIMC. VIMC electromyography (EMG) amplitude, VIMC duration, and perceived VIMC intensity were measured to ensure consistency of VIMC between days. RESULTS: VIMC EMG amplitude, duration, and perceived intensity were similar between days (P > 0.05). VIMC lowered TFc ; baseline TFc (18 ± 6 Hz) was higher than 5-min (14 ± 6 Hz), 30-min (14 ± 5 Hz), and 60-min TFc (14 ± 5 Hz; P < 0.05). DISCUSSION: Acute VIMCs increase cramp susceptibility. Clinicians should apply treatments for at least 60 min postcramp to decrease the probability of cramp recurrence. Muscle Nerve 56: E95-E99, 2017.

Thermoregulatory and Perceptual Effects of a Percooling Garment Worn Underneath an American Football Uniform.

Keen, ML, Miller, KC, and Zuhl, MN. Thermoregulatory and perceptual effects of a percooling garment worn underneath an American football uniform. J Strength Cond Res 31(11): 2983-2991, 2017-American football athletes are at the highest risk of developing exertional heat illness (EHI). We investigated whether percooling (i.e., cooling during exercise) garments affected perceptual or physiological variables in individuals exercising in the heat while wearing football uniforms. Twelve male participants (age = 24 ± 4 year, mass = 80.1 ± 8.5 kg, height = 182.5 ± 10.4 cm) completed this cross-over, counterbalanced study. On day 1, we measured peak oxygen consumption (V[Combining Dot Above]O2). On days 2 and 3, participants wore percooling garments with (ICE) or without (CON) ice packs over the femoral and brachial arteries. They donned a football uniform and completed 3, 20-minute bouts of treadmill exercise at ∼50% of peak V[Combining Dot Above]O2 (∼33° C, ∼42% relative humidity) followed by a 10-minute rest period. Ice packs were replaced every 20 minutes. Rating of perceived exertion (RPE), thermal sensation, and thirst sensation were measured before and after each exercise bout. Environmental symptoms questionnaire (ESQ) responses and urine specific gravity (Usg) were measured pretesting and after the last exercise bout. V[Combining Dot Above]O2, change in heart rate (ΔHR), and change in rectal temperature (ΔTrec) were measured every 5 minutes. Sweat rate, sweat volume, and percent hypohydration were calculated. No interactions (F17,187 ≤ 1.6, p ≥ 0.1) or main effect of cooling condition (F1,11 ≤ 1.4, p ≥ 0.26) occurred for ΔTrec, ΔHR, thermal sensation, thirst, RPE, ESQ, or Usg. No differences between conditions occurred for sweat volume, sweat rate, or percent hypohydration (t11 ≤ 0.7, p ≥ 0.25). V[Combining Dot Above]O2 differed between conditions over time (F15,165 = 3.3, p < 0.001); ICE was lower than CON at 30, 55, and 70 minutes (p ≤ 0.05). It is unlikely that these garments would prevent EHI or minimize dehydration in football athletes.

Should Cooling Vests Be Used to Treat Exertional Heatstroke? A Critically Appraised Topic.

Clinical Scenario: Exercise performed in hot and humid environments increases core body temperature (TC). If TC exceeds 40.5°C for prolonged periods of time, exertional heat stroke (EHS) may occur. EHS is a leading cause of sudden death in athletes. Mortality and morbidity increase the longer the patient's TC remains above 40.5°C; thus, it is imperative to initiate cooling as quickly as possible. Acceptable cooling rates in EHS situations are 0.08-0.15°C/min, while ideal cooling rates are above 0.16°C/min. Cooling vests are popular alternatives for cooling hyperthermic adults. Most vests cover the anterior and posterior torso and have varying numbers of pouches for phase-change materials (eg, gel packs); some vests only use circulating water to cool. While cooling vests offer several advantages (eg, portability), studies demonstrating their effectiveness at rapidly reducing TC in EHS scenarios are limited. CLINICAL QUESTION: Are TC cooling rates acceptable (ie, >0.08°C/min) when hyperthermic humans are treated with cooling vests postexercise? SUMMARY OF FINDINGS: No significant differences in TC cooling rates occurred between cooling vests and no cooling vests. Cooling rates across all studies were ≤0.053°C/min. Clinical Bottom Line: Cooling vests do not provide acceptable cooling rates of hyperthermic humans postexercise and should not be used to treat EHS. Instead, EHS patients should be treated with cold-water immersion within 30 min of collapse to avoid central nervous system dysfunction and organ failure. Strength of Recommendation: Strong evidence (eg, level 2 studies with PEDro scores ≥5) suggests that cooling vests do not reduce TC quickly and thus should not be used in EHS scenarios.

Can Temperate-Water Immersion Effectively Reduce Rectal Temperature in Exertional Heat Stroke? A Critically Appraised Topic.

Clinical Scenario: Exertional heat stroke (EHS) is a medical emergency which, if left untreated, can result in death. The standard of care for EHS patients includes confirmation of hyperthermia via rectal temperature (Trec) and then immediate cold-water immersion (CWI). While CWI is the fastest way to reduce Trec, it may be difficult to lower and maintain water bath temperature in the recommended ranges (1.7°C-15°C [35°F-59°F]) because of limited access to ice and/or the bath being exposed to high ambient temperatures for long periods of time. Determining if Trec cooling rates are acceptable (ie, >0.08°C/min) when significantly hyperthermic humans are immersed in temperate water (ie, ≥20°C [68°F]) has applications for how EHS patients are treated in the field. CLINICAL QUESTION: Are Trec cooling rates acceptable (≥0.08°C/min) when significantly hyperthermic humans are immersed in temperate water? SUMMARY OF FINDINGS: Trec cooling rates of hyperthermic humans immersed in temperate water (≥20°C [68°F]) ranged from 0.06°C/min to 0.19°C/min. The average Trec cooling rate for all examined studies was 0.11±0.06°C/min. Clinical Bottom Line: Temperature water immersion (TWI) provides acceptable (ie, >0.08°C/min) Trec cooling rates for hyperthermic humans post-exercise. However, CWI cooling rates are higher and should be used if feasible (eg, access to ice, shaded treatment areas). Strength of Recommendation: The majority of evidence (eg, Level 2 studies with PEDro scores ≥5) suggests TWI provides acceptable, though not ideal, Trec cooling. If possible, CWI should be used instead of TWI in EHS scenarios.

Does a Reduction in Serum Sodium Concentration or Serum Potassium Concentration Increase the Prevalence of Exercise-Associated Muscle Cramps?

CLINICAL SCENARIO: Although exercise-associated muscle cramps (EAMC) are common in ultradistance runners and athletes in general, their etiology remains unclear. EAMC are painful, sudden, involuntary contractions of skeletal muscle occurring during or after exercise and are recognized by visible bulging or knotting of the whole, or part of, a muscle. Many clinicians believe EAMC occur after an imbalance in electrolyte concentrations, specifically serum sodium concentration ([Na+]s) and serum potassium concentration ([K+]s). Studies that have established a link between EAMC occurrence and serum electrolyte concentrations after an athletic event are unhelpful. Focused Clinical Question: Are [Na+]s and [K+]s different in athletes who experience EAMC than noncrampers?

Golgi tendon organ reflex inhibition following manually applied acute static stretching.

Golgi tendon organ disinhibition may contribute to exercise-associated muscle cramp (henceforth referred to as "cramps") genesis. Static stretching pre-exercise is prescribed to prevent cramps based on the assumption golgi tendon organ inhibition remains elevated post-stretching. We determined whether stretching increased gastrocnemius golgi tendon organ inhibition and, if so, the time course of this inhibition post-stretching. Twelve participants' dominant limb medial gastrocnemius inhibition was measured before, and at 1, 5, 10, 15 and 30 min after investigators applied three, 1-min duration stretches. Participants maintained voluntary contraction intensities of 5% of their maximum while the Achilles tendon was stimulated transcutaneously 50 times. Five-hundred millisecond epochs of raw electromyographic activity were band-pass filtered, full-wave rectified and averaged. An algorithm identified inhibitory points and calculated the area, maximum and duration of inhibition. Area of inhibition (F1,14 = 1.5, P = 0.25), maximum inhibition (F1,14 = 0.2, P = 0.72) and duration of inhibition (F1,14 = 1.5, P = 0.24) were unaffected by static stretching over the 30-min post-stretching period. If pre-stretching does prevent fatigue-induced cramping, the mechanism is unlikely to involve the autoinhibition produced by the golgi tendon organ reflex. Further empirical research is needed to validate the proposed link between static stretching and cramping and then to investigate alternative mechanisms.

Body Bag Cooling with Two Different Water Temperatures for the Treatment of Hyperthermia.

INTRODUCTION: Exertional heatstroke (EHS) is a life-threatening condition that requires quick recognition and cooling for survival. Experts recommend using cooling modalities that reduce rectal temperature (TREC) faster than 0.16°C/min though rates above 0.08°C/min are considered "acceptable." Hyperthermic individuals treated in body bags filled with ice water (∼3°C) have excellent cooling rates (0.28 ± 0.09°C/min). However, clinicians may not have access to large amounts of ice or ice water when treating EHS victims. The purpose of this study was to determine if using a body bag filled with water near the upper limits of expert recommendations for EHS treatment would produce acceptable (>0.08°C/min) or "ideal (>0.16°C/min)" TREC cooling rates or different nadir values.METHODS: A total of 12 individuals (9 men, 3 women; age: 21 ± 2 yr; mass: 74.6 ± 10.2 kg; height: 179.5 ± 9.6 cm) exercised in the heat until TREC was 39.5°C. They lay supine while 211.4 ± 19.5 L of 10°C (Ten) or 15°C (Fifteen) water was poured into a body bag. Subjects cooled until TREC was 38°C. They exited the body bag and rested in the heat for 10 min.RESULTS: Subjects exercised in similar conditions and for similar durations (Ten = 46.3 ± 8.6 min, Fifteen = 46.2 ± 7.8 min). TREC cooling rates were faster in Ten than Fifteen (Ten = 0.18 ± 0.07°C/min, Fifteen = 0.14 ± 0.09°C/min). TREC nadir was slightly higher in Fifteen (37.3 ± 0.2°C) than Ten (37.1 ± 0.3°C).DISCUSSION: Body bag cooling rates met expert definitions of acceptable (Fifteen) and ideal (Ten) for EHS treatment. This information is valuable for clinicians who do not have access to or the resources for ice water cooling to treat EHS.Miller KC, Amaria NY. Body bag cooling with two different water temperatures for the treatment of hyperthermia. Aerosp Med Hum Perform. 2024; 95(4):194-199.

Exertional Heatstroke Survivors' Knowledge and Beliefs about Exertional Heatstroke Diagnosis, Treatment, and Return to Play.

CONTEXT: Little information exists regarding what exertional heatstroke (EHS) survivors know and believe about EHS best practices. Understanding this would help clinicians focus educational efforts to ensure survival and safe return-to-play following EHS. OBJECTIVE: We sought to better understand what EHS survivors knew about EHS seriousness (e.g., lethality, short- and long-term effects), diagnosis and treatment procedures, and recovery. Design: Multi-year, cross-sectional, descriptive design. SETTING: An 11.3-km road race located in the Northeastern United States in August 2022 and 2023. PATIENTS OR OTHER PARTICIPANTS: Forty-two of 62 runners with EHS (15 women, 27 men; age: 33±15 y; pre-treatment rectal temperature [TREC]: 41.5±0.9°C). INTERVENTIONS: Medical professionals evaluated runners requiring medical attention at the finish line. If they observed TREC ≥40°C with concomitant central nervous system dysfunction (CNS) EHS was diagnosed and patients were immersed in a 189.3-L tub filled with ice-water. Before medical discharge, we asked EHS survivors 15 questions about their experience and knowledge of select EHS best practices. Survey items were piloted and validated by experts and laypersons a priori (content validity index ≥0.88 for items and scale). MAIN OUTCOME MEASURES: Survey responses. RESULTS: Sixty-seven percent (28/42) of patients identified EHS as potentially fatal and 76% (32/42) indicated it negatively affected health. Seventy-nine percent (33/42) correctly identified TREC as the best temperature site to diagnose EHS. Most patients (74%, 31/42) anticipated returning to normal exercise within 1 week post-EHS; 69% (29/42) stated EHS would not impact future race participation. Patients (69%, 29/42) indicated it was important to tell their primary care physician about their EHS. CONCLUSIONS: Our patients were knowledgeable on the potential seriousness and adverse health effects of EHS and the necessity of TREC for diagnosis. However, educational efforts should be directed towards helping patients understand safe recovery and return-to-play timelines following EHS.