How to design and establish a national school-based physical fitness monitoring and surveillance system for children and adolescents: A 10-step approach recommended by the FitBack network.

BACKGROUND: Providing individual- and population-level data on children's physical fitness (PF) is a crucial public health and education priority. However, few national fitness monitoring or surveillance systems are currently in practice internationally. We aim to summarize the current European PF monitoring and surveillance systems for school-aged children and to provide experience-based guidelines on how to design such systems. METHODS: The FitBack network consists of experts from diverse backgrounds with the common interest to improve the accessibility of PF monitoring for young people globally. Through FitBack network, we identified and compared the national or regional PF monitoring and surveillance systems currently in operation across Europe. We formulated a 10-step approach for designing and establishing one's own system, based on analysis of experienced strengths, weaknesses, opportunities, and threats to monitoring childhood fitness. RESULTS: We identified a total of eight PF monitoring systems in Finland, France, Galicia of Spain, Hungary, Lithuania, Portugal, Serbia, and Slovenia. The FitBack network recommends the following steps for designing and establishing one's own system: (1) set up mission statements and aims, (2) involve stakeholders, (3) utilize scientific background, (4) governance structure, (5) ensure sufficient funding, (6) data management planning, (7) provide meaningful feedback, (8) conduct pilot testing, (9) plan implementation process, and (10) invest in communication with stakeholders. CONCLUSIONS: This study provides an updated overview of the best practices for school-aged children's fitness monitoring and surveillance in Europe. Additionally, it offers a 10-step approach to assist in the creation of similar systems in Europe or globally.

Children With Cardiac Disease and Heat Exposure: Catastrophic Converging Consequences?

The detrimental impact of extreme heat exposure on the health and well-being of children is widely acknowledged. The direct and indirect effects of climate change have led to an increased risk of certain cardiovascular events which may be particularly harmful to children who are born with, or develop, heart disease. PURPOSE: To highlight the worrying paucity of investigative research aimed at differentiating how higher ambient temperatures further tax an already compromised cardiovascular system in children. METHODS: This commentary describes basic thermoregulatory concepts relevant to the healthy pediatric population and summarizes common heart diseases observed in this population. RESULTS: We describe how heat stress and exercise are important factors clinicians should more readily consider when treating children with heart disease. Countermeasures to physical inactivity are suggested for children, parents, clinicians, and policymakers to consider. CONCLUSIONS: As sudden, excessive heat exposures continue to impact our rapidly warming world, vulnerable populations like children with underlying heart conditions are at greater heat health risk, especially when coupled with the negative physical activity and fitness trends observed worldwide.

Challenges of social change: The 2021 Republic of Slovenia report card on physical activity of children and adolescents.

Background: Slovenian children are facing considerable health challenges from the rapid social changes that influence their opportunity to engage in daily physical activity. Objective: To overlay the social changes to the established Report Card model as a means of contextualising the extreme changes in physical activity and fitness observed over several years. Methods: Benchmarks were graded for 10 core indicators, plus two (Sleep, Seasonal Variations). Active Healthy Kids Slovenia members met (predominantly via zoom) liaising with team leader(s) on a flexible, individual basis, based on coronavirus disease 2019 (COVID-19) regulations, over the ∼2-year assessment period of the project. Data were separated to the years prior to, 'pre' 2018-2020, and 'during' the global pandemic (2020-2021). Where sufficient data existed for both timeframes, grades were averaged to produce an overall grade. Results: Grade results are expressed as pre/during/final grade, where the final grade (bolded) is a straight average of the two preceding time epochs: Overall Physical Activity (A-/A-/A-), Organized Sport and Physical Activity (C+/C/C), Active Play (D/C+/C), Active Transport (C/INC/C), Sedentary Behaviour (B/C/C+), Physical Fitness (A+/A-/A), Family and Peers (B+/INC/B+), Schools (A/A/A), Community and Environment (A+/A+/A+), Government (A/F/D), Sleep (D-/INC/D-), Seasonal Variations (D/C-/D+). Conclusion: Although Slovenia has some of the most consistently physically-active children in the world, the effects of the COVID-19 pandemic exerted significant reductions in physical activity opportunities, and especially when coupled with funding re-distributions, resulted in the steepest decline of child physical fitness observed within the >35-year history of Slovenia's well-established national fitness surveillance system.

Heat risk exacerbation potential for neurology patients during the COVID-19 pandemic and related isolation.

COVID-19 may increase the risk of heat-related symptoms during hot weather since vulnerable populations, including the elderly and those with neurological disabilities, must continue to self-isolate, often indoors. Within the chronic neurological patient population, indoor conditions in summer months present a hazard because of impaired and/or altered thermoregulation, including poor hydration status due to both autonomic and behavioral dysfunction(s). To address this increased risk, telemedicine protocols should include an assessment of the patient's environmental parameters, and when combined with physiological data from wearable devices, identify those with neurological diseases who are at higher risk of heat illness. Personalized medicine during times of self-isolation must be encouraged, and using smart technology in ambient assisted living solutions, including e-health to monitor physiological parameters are highly recommended, not only during extreme weather conditions but also during times of increased isolation and vulnerability.

Effects of a cooling vest with sham condition on walking capacity in heat-sensitive people with Multiple Sclerosis.

PURPOSE: Heat sensitivity is a common contraindication in people with Multiple Sclerosis (pwMS), and physical fatigue is one of the most frequently reported symptoms that can affect quality of life. Increases in body temperature may exacerbate fatigue and heat-related symptoms. Decreasing body temperature via cooling devices may mitigate disease symptoms and improve physical abilities and quality of life. This study evaluates the effects of a cooling vest with sham condition on walking capacity using a commercially-available cooling vest specifically designed for pwMS. METHODS: A counter-balanced, cross-over design was used to assess the effects of a cooling vest (CryoVest Comfort, CryoInnov, France) (COLD) from a menthol-induced sham condition (CON) on ground walking time to exhaustion (Tex, s) and distance at exhaustion (Dex, m) in ambulatory pwMS. Secondary outcomes were heart rate (HR, bpm), thermal sensation (Tsens), skin chest (Tchest) and back (Tback) temperature. RESULTS: Ten females with Multiple Sclerosis (59 ± 9 years, EDSS 3.0-5.5) participated to the study. During COLD, pwMS walked significantly longer (1896 ± 602 vs. 1399 ± 404 s, p < 0.001) and farther (1879 ± 539 vs. 1302 ± 318 m, p < 0.001) than CON. Importantly, Tsens and HR at exhaustion were not significantly different between conditions, although Tchest (- 2.7 ± 1.8 °C, p < 0.01) and Tback (- 3.9 ± 1.8 °C, p < 0.001) were lower at volitional fatigue during COLD. CONCLUSION: The lightweight cooling vest improved total walking time and distance in heat-sensitive pwMS. These physiological improvements were likely due to feeling perceptually cooler in the COLD trial, compared to the corresponding point of fatigue in the CON condition.

Fluid balance and hydration status in combat sport Olympic athletes: a systematic review with meta-analysis of controlled and uncontrolled studies.

PURPOSE: Athletes in Olympic combat sports experience body water fluctuations resulting from training and intentional dehydration when making weight. Despite the popularity of urine specific gravity (USG) and urine osmolality (UOSM) measurement in characterizing fluid fluctuations, their utility remains questioned. This systematic review/meta-analysis examined the utility of urinary hydration indices in laboratory and field settings in Olympic combat sport athletes. METHODS: 27 articles met the inclusion criteria for systematic review, 15 studies were included in the meta-analysis; with USG and UOSM the main outcome variables. Meta-regression analyses evaluated the interrelationship among body mass (BM), fluid intake, and urine measures. RESULTS: Significant USG alterations were observed following different sampling time frames: dehydration (ES 0.59; 95% CI 0.46-0.72; p = 0.001), follow-up period (ES 0.31; 95% CI 0.11-0.50; p = 0.002) and rehydration (ES - 0.34; 95% CI - 0.56 to - 0.12; p = 0.003). Direct comparison of laboratory (ES 0.20; 95% CI - 0.19 to 0.59; p = 0.324) and field (ES 0.35; 95% CI 0.14-0.56; p = 0.001) sampling showed marginally trivial and small effects. Small effects on UOSM were observed following dehydration (ES 0.31; 95% CI 0.12-0.74, p = 0.15), follow-up period (ES 0.39; 95% CI 0.08-0.70, p = 0.015) and rehydration (ES - 0.45; 95% CI - 0.60 to 0.30, p = 0.001). Meta-regression analysis suggests only fluid intake predicts USG alterations (p = 0.044) during rehydration protocols. CONCLUSIONS: There were likely small changes in both USG and UOSM readings across all experimental conditions, with moderate-to-large heterogeneity in all studies, except for USG readings during dehydration protocols. The meta-regression failed to provide conclusive evidence concerning the interrelationship among urine measures, BM fluctuations, and fluid intake.

Ski-Everest (8848 m) Expedition: Digit Skin Temperature Responses to Cold Immersion May Reflect Susceptibility to Cold Injury.

INTRODUCTION: We tested the hypothesis that individual susceptibility to freezing cold injury might be reflected in an attenuated cold-induced vasodilatation (CIVD) response by comparing the CIVD responses of an elite alpinist with a history of freezing cold injury in the feet (case alpinist) with those of an age- and ability- matched noninjured alpinists control group (controls). According to this hypothesis, the vasomotor responses to a CIVD test of the case alpinist would represent a pathophysiological response when compared with the normal physiological response of a noninjured cohort. METHODS: The case alpinist and the controls in the cohort group conducted a cold water immersion test comprising sequential immersion of a hand and foot for 5 min in 35°C water, followed by a 30-min immersion in 8°C water and a 10-min recovery period in room air. During this test we monitored the finger and toe skin temperatures. RESULTS: The case alpinist had a significantly attenuated CIVD response and a lower skin temperature in all injured and noninjured digits during immersion (∼2°C lower than in the control group) and an attenuated recovery of finger skin temperatures (∼6°C lower than in the control group). CONCLUSIONS: The attenuated CIVD response of the case alpinist may reflect a previously unrecognized enhanced susceptibility to frostbite. In addition to the poor vasomotor response observed in the injured toes, he also exhibited a poor vasomotor response in his noninjured fingers. The results of the present study indicate that a test of vasomotor activity during thermal stress may identify individuals predisposed to cold injury.

Fluid Intake Habits in Type 1 Diabetes Individuals during Typical Training Bouts.

BACKGROUND/AIMS: Hyperglycemia may influence the hydration status in diabetic individuals. During exercise, type 1 diabetes mellitus (T1DM) individuals may be challenged by a higher risk of dehydration due to a combination of fluid losses from sweat and increased urine output via glycosuria. So far, no study has characterised spontaneous fluid intake in T1DM individuals during active trainings. METHODS: A validated questionnaire was used to assess T1DM participants' diabetes therapy, sports characteristics and fluid intake during training; results were then compared to an age- and sport-matched sample of non-diabetic individuals. RESULTS: Ninety individuals completed the survey (n = 45 T1DM individuals, n = 45 matched controls). A proportion of T1DM -individuals reported blood glucose levels greater than 10.0 mmol at both the start (28.9%) and end (24.4%) of the exercise. The mean self-reported fluid intake was greater in T1DM (0.60 ± 0.47 L·h-1) compared to that of the control (0.37 ± 0.28 L·h-1, p < 0.05). In spite of drinking fluid volumes in line with international guidelines, 84.4% of those with T1DM reported that they were still feeling thirsty at the end of their training session. CONCLUSIONS: T1DM individuals self-report spontaneously consuming fluid adequate volumes suggested by sport nutrition guidelines for non-diabetic athletes. Discrepancies in the T1DM subjectively reported feelings of thirst suggest that more education on hydration during exercise is needed for this population to adequately compensate for elevated blood glucose levels. It remains to be established whether fluid volumes suggested for healthy athletes are adequate for maintaining euhydration in T1DM patients due to their altered diuresis.

Koroska 8000 Himalayan expedition: digit responses to cold stress following ascent to Broadpeak (Pakistan, 8051 m).

PURPOSE: Cold-induced vasodilatation (CIVD) is a peripheral blood flow response, observed in both the hands and feet. Exercise has been shown to enhance the response, specifically by increasing mean skin temperatures (Tsk), in part due to the increased number of CIVD waves. In contrast, hypobaric hypoxia has been suggested to impair digit skin temperature responses, particularly during subsequent hand rewarming following the cold stimulus. This study examined the combined effect of exercise and hypobaric hypoxia on the CIVD response. We compared the CIVD responses in the digits of both the hands and feet of a team of alpinists (N = 5) before and after a 35-day Himalayan expedition to Broadpeak, Pakistan (8051 m). METHODS: Five elite alpinists participated in hand and foot cold water immersion tests 20 days before and immediately upon return from their expedition. RESULTS: The alpinists summited successfully without supplemental oxygen. Post-expedition, all alpinists demonstrated higher minimum Tsk in their hands (pre: 9.9 ± 1.1, post: 10.1 ± 0.7 °C, p = 0.031). Four alpinists had either greater CIVD waves, and, consequently, higher mean Tsk in their hands, or higher recovery temperatures (pre: 26.0 ± 5.5 °C post: 31.0 ± 4.1 °C, p = 0.052), or faster rewarming rate (pre: 2.6 ± 0.5 °C min-1 post: 3.1 ± 0.4 °C min-1,p = 0.052). In the feet, the responses varied: 1/5 had higher wave amplitudes and 1/5 had higher passive recovery temperatures, whereas 3/5 had lower mean toe temperatures during cold exposure. CONCLUSIONS: The results of the cold stress test suggest after a 35-day Himalayan expedition, alpinists experienced a slight cold adaptation of the hands, but not the feet.

The effect of a Live-high Train-high exercise regimen on behavioural temperature regulation.

PURPOSE: Acute hypoxia alters the threshold for sensation of cutaneous thermal stimuli. We hypothesised that hypoxia-induced alterations in cutaneous temperature sensation may lead to modulation of the perception of temperature, ultimately influencing behavioural thermoregulation and that the magnitude of this effect could be influenced by daily physical training. METHODS: Fourteen men were confined 10 days to a normobaric hypoxic environment (PIO2 = 88.2 ± 0.6 mmHg, corresponding to 4175 m elevation). Subjects were randomly assigned to a non-exercising (Live-high, LH, N = 6), or exercising group (Live-high Train-high, LH-TH, N = 8) comprised of 1-h bouts of cycle ergometry, twice daily, at a work-rate equivalent to 50% hypoxic peak power output. A subset of subjects (N = 5) also completed a control trial under normoxic conditions. The thermal comfort zone (TCZ) was determined in normoxia, and during hypoxic confinement days 2 (HC2) and 10 (HC10) in both groups using a water-perfused suit in which water temperature was regulated by the subjects within a range, they deemed thermally comfortable. Mean skin temperature and proximal-distal temperature gradients (two sites: forearm-fingertip, calf-toe) were recorded each minute throughout the 60-min protocol. RESULTS: The average width of the TCZ did not differ between the control group (9.0 ± 6.9 °C), and the LH and LH-TH groups on days HC2 (7.2 ± 4.2 °C) and HC10 (10.2 ± 7.5 °C) of the hypoxic exposure (p = 0.256). [Formula: see text] was marginally higher on HC2 (35.9 ± 1.0 °C) compared to control (34.9 ± 0.8 °C, p = 0.040), but not on HC10 (35.6 ± 1.0 °C), reflecting the responses of hand perfusion. CONCLUSION: There was a little systematic effect of hypoxia or exercise training on TCZ magnitude or boundary temperatures.

Fluid balance and hydration assessment during the weight-stable preparation phase in elite youth boxers.

This study investigated (i) the prevalence of hypohydration and (ii) association between urinary indices of hydration status and confounding factors (e.g., urine protein content, water intake) in elite youth boxers during their weight-stable phase before competition. Sixteen national champion boxers (all male, 17 ± 1 y) were measured on 3 occasions (baseline, day 3, day 10), 30-day prior to competition. Body mass, total body water, urine specific gravity (USG), osmolality (UOSM) and total protein content (TPC) were evaluated to determine hydration status and fluid balance. Overall macronutrient and water intake were assessed using dietary records. Both UOSM and USG increased from day 3 to day 10 by 16% and 0.4% (P < 0.001), despite athletes being in their weight-stability period, and regardless of ad libitum fluid intake. Hypohydration was universally prevalent among all athletes on both test days with USG: 1.027 ± 0.003 g · mL-1 and UOSM: 1035 ± 108 mOsmol · kg-1. An inverse association between mean UOSM values and mean water intake was observed (R = -0.52, P = 0.04), while TPC was not associated with any urinary dehydration markers (USG, P = 0.51; UOSM, P = 0.61). The present outcomes find that the most prevalent urinary dehydration markers used to classify hydration status in competition exhibit large variability, even during weight-stable periods.

Effect of exercise on night periodic breathing and loop gain during hypoxic confinement.

BACKGROUND AND OBJECTIVE: Hypoxic exercise exacerbates periodic breathing in otherwise healthy, awake humans. Interactions between sleep, exercise and hypoxic exposure have not been fully elucidated. METHODS: Fourteen men were confined 10 days to a simulated altitude of 4175 m (FIO2 = 0.139; PIO2 = 88 mm Hg). They were randomly assigned to an exercise intervention of 2 × 60-min cycle exercise/day at 50% of their hypoxia-specific peak power output (exercise, n = 8), or they completed no exercise (control, n = 6, random order). Sleep and breathing were objectively assessed via full polysomnography on night 1, after 14-h acute exposure (N1), and again on night 10 (N10). RESULTS: The exercise group spent more time in light sleep than control on N10 (95% confidence interval (CI): 8.5-15.0%; P = 0.013) and experienced more stage shifts (CI: 13-44; P = 0.023) on both nights compared with control. The exercise group experienced more apnoea-hypopnoea (AH) events per hour compared with control (CI: 1-110; P = 0.046); AH events that were associated with night desaturations were also higher on N1 (exercise: 397 ± 320, control: 124 ± 205, P = 0.047) and N10 (exercise: 375 ± 229, control: 110 ± 138, P = 0.028, CI: 49-489 total events; P = 0.020). The length of hyperpnoea was increased from 12.8 ± 2.2 s on N1 to 14.6 ± 2.7 s on N10 (P = 0.008), and thus, total cycle length also increased (P = 0.002) in both cohorts. Mean pooled duty ratios were 0.68 ± 0.02 on N1 and 0.69 ± 0.02 on N10 (group effect P = 0.617). CONCLUSION: Daily, moderate-intensity exercise in normobaric hypoxia equivalent to 4175 m exacerbated AH events, and negatively affected sleep architecture in exercisers compared with matched controls.

Finger and Toe Temperature Responses to Cold After Freezing Cold Injury in Elite Alpinists.

OBJECTIVE: To assess whether previous freezing cold injuries (FCI) would affect digit skin temperatures and rewarming rates during a follow-up cold stress test protocol. DESIGN: Nonrandomized control trial. METHODS: Twenty elite alpinists participated; alpinists with previous FCI requiring digit amputations (injured, INJ: n = 10 total, n = 8 male) were compared with ability-matched, uninjured alpinists (control, CON: n = 10, all male). Digit skin temperature was measured using infrared thermography as an index of peripheral digit perfusion after a cold stress test, which consisted of 30 minutes of immersion in 8°C water. RESULTS: The INJ alpinists' injured toes were warmer (approximately 6%) than their uninjured toes immediately after cold immersion (95% CI, 0.01°C to 1.00°C; P = .05); there were no differences between the rates of rewarming of injured and uninjured toes (INJ, 0.5° ± 0.1°C/min; CON, 0.7° ± 0.3°C/min; P = .16). Although the INJ alpinists had colder injured fingers immediately after the 35°C warm bath compared with their own uninjured fingers (32.2° ± 2.0°C vs 34.5° ± 0.5°C; P = .02), there were no differences observed between the rates of rewarming of injured and uninjured fingers after cold exposure (INJ, 1.1° ± 0.2°C/min; CON, 1.3° ± 0.5°C/min; P = .22). CONCLUSIONS: Even after FCI that requires digit amputation, there is no evidence of different tissue rates of rewarming between the injured and uninjured fingers or toes of elite alpinists.

Impact of hypocapnia and cerebral perfusion on orthostatic tolerance.

We examined two novel hypotheses: (1) that orthostatic tolerance (OT) would be prolonged when hyperventilatory-induced hypocapnia (and hence cerebral hypoperfusion) was prevented; and (2) that pharmacological reductions in cerebral blood flow (CBF) at baseline would lower the 'CBF reserve', and ultimately reduce OT. In study 1 (n = 24; aged 25 ± 4 years) participants underwent progressive lower-body negative pressure (LBNP) until pre-syncope; end-tidal carbon dioxide (P ET , CO 2) was clamped at baseline levels (isocapnic trial) or uncontrolled. In study 2 (n = 10; aged 25 ± 4 years), CBF was pharmacologically reduced by administration of indomethacin (INDO; 1.2 mg kg(-1)) or unaltered (placebo) followed by LBNP to pre-syncope. Beat-by-beat measurements of middle cerebral artery blood flow velocity (MCAv; transcranial Doppler), heart rate (ECG), blood pressure (BP; Finometer) and end-tidal gases were obtained continuously. In a subset of subjects' arterial-to-jugular venous differences were obtained to examine the independent impact of hypocapnia or cerebral hypoperfusion (following INDO) on cerebral oxygen delivery and extraction. In study 1, during the isocapnic trial, P ET , CO 2 was successfully clamped at baseline levels at pre-syncope (38.3 ± 2.7 vs. 38.5 ± 2.5 mmHg respectively; P = 0.50). In the uncontrolled trial, P ET , CO 2 at pre-syncope was reduced by 10.9 ± 3.9 mmHg (P ≤ 0.001). Compared to the isocapnic trial, the decline in mean MCAv was 15 ± 4 cm s(-1) (35%; P ≤ 0.001) greater in the uncontrolled trial, yet the time to pre-syncope was comparable between trials (544 ± 130 vs. 572 ± 180 s; P = 0.30). In study 2, compared to placebo, INDO reduced resting MCAv by 19 ± 4 cm s(-1) (31%; P ≤ 0.001), but time to pre-syncope remained similar between trials (placebo: 1123 ± 138 s vs. INDO: 1175 ± 212 s; P = 0.53). The brain extracted more oxygen in face of hypocapnia (34% to 53%) or cerebral hypoperfusion (34% to 57%) to compensate for reductions in delivery. In summary, cerebral hypoperfusion either at rest or induced by hypocapnia at pre-syncope does not impact OT, probably due to a compensatory increase in oxygen extraction.

The separate and combined effects of hypoxia and sustained recumbency/inactivity on sleep architecture.

PURPOSE: The objective was to determine the separate and combined effects of hypoxia and inactivity/unloading on sleep architecture during a 10-day period of confinement. METHODS: Ten subjects participated in three 10-day trials in random order: hypoxic ambulatory (HAMB), hypoxic bedrest (HBR), and normoxic bedrest (NBR). During the HAMB and HBR trials, subjects were confined to a hypoxic facility. The hypoxia profile was: simulated altitude of 2,990 m on day 1, 3,380 m on day 2, and 3,881 m on day 3. In the NBR and HBR trials, subjects maintained a horizontal position throughout the confinement period. During each trial, sleep polysomnography was conducted one night prior to (baseline; altitude of facility is 940 m) and on the first (NT1, altitude 2,990 m) and tenth (NT10, altitude 3,881 m) night of the 10-day intervention. RESULTS: Average time in sleep stage 1 decreased from NT1 to NT10 irrespective of trial. Overall incidence and time spent in periodic breathing increased from NT1 to NT10 in both HAMB and HBR. During NT1, both HAMB and HBR reduced slow-wave sleep and increased light sleep, whereas NBR and HBR increased the number of awakenings/night. There were fewer awakenings during HAMB than NBR. CONCLUSIONS: Acute exposure to both hypoxia and bedrest (HBR) results in greater sleep fragmentation due to more awakenings attributed to bedrest, and lighter sleep as a result of reduced slow wave sleep caused by the hypoxic environment.

Moving in a hotter world: Maintaining adequate childhood fitness as a climate change countermeasure.

Children cope with high temperatures differently than adults do, largely because of slight alterations in their body proportions and heat loss mechanisms compared to fully mature humans. Paradoxically, all current tools of assessing thermal strain have been developed on adults. As the Earth's warming continues to accelerate, children are set to bear the health risk brunt of rising global temperatures. Physical fitness has a direct impact on heat tolerance, yet children are less fit and more obese than ever before. Longitudinal research reveals that children have 30% lower aerobic fitness than their parents did at the same age; this deficit is greater than can be recovered by training alone. So, as the planet's climate and weather patterns become more extreme, children may become less capable of tolerating it. This comprehensive review provides an outline of child thermoregulation and assessment of thermal strain, before moving to summarize how aerobic fitness can modulate hyperthermia, heat tolerance, and behavioral thermoregulation in this under-researched population. The nature of child physical activity, physical fitness, and one's physical literacy journey as an interconnected paradigm for promoting climate change resilience is explored. Finally, future research foci are suggested to encourage continued exploration of this dynamic field, notable since more extreme, multifactorial environmental stressors are expected to continue challenging the physiological strain of the human population for the foreseeable future.

24-h movement behaviour, thermal perception, thirst, and heat management strategies of children and adults during heat alerts: a pilot study.

Background: Heat waves caused by climate change are increasingly challenging the wellbeing of individuals across the lifespan. Current efforts to understand the thermal perceptions and behaviours of people throughout the lifespan during heat waves are limited. Methods: Since June 2021, the Active Heatwave project has been recruiting households to better understand how individuals perceive, cope, and behave during heat waves. Using our novel web platform, participants were prompted to answer our Heat Alert Survey on days when a participants geolocation corresponded to a broadcasted local heat alert. Participants provided 24-h movement behaviour, thirst, thermal perception, and cooling strategies via validated questionnaires. Results: A total of 285 participants (118 children) from 60 distinct weather station locations globally participated between June and September 2021 and 2022. At least 1 heat alert (834 total) were identified from 95% (57/60) of the weather stations. Children reported spending more time performing vigorous intensity exercise compared to adults (p < 0.05), but no differences in thermal sensation, thermal comfort, or thirst sensation (all p > 0.31) were observed. For thirst management, 88% of respondents used water to relieve thirst, although notably, 15% of adults reported using alcohol. Regardless of age, staying indoors was the most common heat management strategy, whereas visiting cooling centres was the least. Conclusion: The present study presents a proof-of-concept combining local heat alert notifications with e-questionnaires for collecting near-real-time perceptual and behavioural data for both children and adults during heat waves. The observed patterns of behaviour suggest that present public heat-health guidelines are often ignored, children engage in fewer heat management strategies compared to adults, and these disparities highlight the need to improve public health communication and knowledge dissemination around promoting effective and accessible cooling solutions for children and adults.

Effectiveness of a population-scaled, school-based physical activity intervention for the prevention of childhood obesity.

OBJECTIVE: The aim of this study was to examine the effectiveness of a real-world, population-scaled, school-based physical activity (PA) intervention that provided two to three additional physical education lessons per week to children aged 6 to 14 years in Slovenia. METHODS: More than 34,000 participants from over 200 schools were compared with a similar number of nonparticipants from the same schools. Generalized estimating equations were used to estimate the effects of differing levels of exposure to the intervention (i.e., from 1-5 years) on BMI in children with normal weight, overweight, or obesity at baseline. RESULTS: BMI was lower in the intervention group, irrespective of participation duration or baseline weight status. The difference in BMI increased with the program duration, with maximal effects being seen after 3 to 4 years of participation, and was consistently larger for children with obesity (peaking at 1.4 kg/m2 [95% CI: 1.0-1.9] for girls with obesity and peaking at 0.9 kg/m2 [95% CI: 0.6-1.3] for boys with obesity). The program started to become effective at reversing obesity after 3 years, whereas the lowest numbers needed to treat (NNTs) were observed after 5 years (NNTs = 17 for girls and 12 for boys). CONCLUSIONS: The population-scaled, school-based PA intervention was effective in preventing and treating obesity. The effects were the greatest in children initially presenting with obesity, such that the program was able to benefit children needing support the most.

Can Primary School Mathematics Performance Be Predicted by Longitudinal Changes in Physical Fitness and Activity Indicators?

OBJECTIVE: To determine to what extent physical fitness indicators and/or moderate to vigorous physical activity (MVPA) may account for final mathematics academic performance (APmath) awarded at the end of primary school. METHODS: School-aged youth were sampled in a repeated-measures, longitudinal design in Grade 6 (∼11 years), and again in Grade 9 (∼14 years). The youth (N = 231, 111 girls) completed a fitness test battery consisting of: flamingo balance test, standing long jump, backward obstacle course, plate tapping, sit ups, sit and reach, handgrip, and 20-m shuttle run. APmath scores were obtained for all children at the end of Grade 5, end of Grade 8, and end of Grade 9 (their final year of primary school). In a sub-sample of Grade 6 youth (N = 50, 29 girls), MVPA was measured objectively via SenseWear Pro Armbands (MVPAOB) for seven consecutive days, with measurements repeated in Grade 9. RESULTS: Math scores decreased from Grade 6 to 9 for both boys and girls (95%CI: -0.89 to -0.53, p < 0.001). MVPAOB was reduced by ∼45.7 min (-33%) from Grade 6 to 9 (p < 0.01). Significant main and interaction effects are noted for each fitness indicator (p < 0.05). A backward stepwise multiple regression analysis determined significant shared variance in final APmath grade to the change scores from Grade 6 to Grade 9 in: ΔAPmath, Δbackward obstacle course, Δsit and reach, and Δsit-ups [R 2 = 0.494, F(4,180) = 43.67, p < 0.0001]. A second regression was performed only for the youth who completed MVPAOB measurements. In this sub-sample, MVPAOB did not significantly contribute to the model. CONCLUSION: Longitudinal changes in youth fitness and their delta change in APmath score accounted for 49.4% of the variance in the final math grade awarded at the end of Grade 9. Aerobic power, upper body strength, and muscular endurance share more common variance to final math grade in boys, whereas whole-body coordination was the more relevant index in girls; this finding suggests that future research exploring the relationship of AP and PF should not be limited to cardiorespiratory fitness, instead encompassing muscular and neuro-muscular components of PF.