Preparing for a hotter climate: A systematic review and meta-analysis of heatwaves and ambulance callouts in Australia.

OBJECTIVE: The objective of this study was to quantify the impact of heatwaves on likelihood of ambulance callouts for Australia. METHODS: A systematic review and meta-analysis was conducted to retrieve and synthesise evidence published from 1 January 2011 to 31 May 2023 about the association between heatwaves and the likelihood of ambulance callouts in Australia. Different heatwave definitions were used ranging from excess heat factor to heatwave defined as a continuous period with temperatures above certain defined thresholds (which varied based on study locations). RESULTS: We included nine papers which met the inclusion criteria for the review. Eight were eligible for the meta-analyses. The multilevel meta-analyses revealed that the likelihood of ambulance callouts for all causes and for cardiovascular diseases increased by 10% (95% confidence interval: 8%, 13%) and 5% (95% confidence interval: 1%, 3%), respectively, during heatwave days. CONCLUSIONS: Exposure to heatwaves is associated with an increased likelihood of ambulance callouts, and there is a dose-response association between heatwave severity and the likelihood of ambulance callouts. IMPLICATIONS FOR PUBLIC HEALTH: The number of heatwave days are going to increase, and this will mean an increase in the likelihood of ambulance callouts, thereby, spotlighting the real burden that heatwaves place on our already stressed healthcare system. The findings of this study underscore the critical need for proactive measures, including the establishment of research initiatives and holistic heat health awareness campaigns, spanning from the individual and community levels to the healthcare system, in order to create a more resilient Australia in the face of heatwave-related challenges.

Heat, heatwaves, and ambulance service use: a systematic review and meta-analysis of epidemiological evidence.

Ambulance data has been reported to be a sensitive indicator of health service use during hot days, but there is no comprehensive summary of the quantitative association between heat and ambulance dispatches. We conducted a systematic review and meta-analysis to retrieve and synthesise evidence published up to 31 August 2022 about the association between heat, prolonged heat (i.e. heatwaves), and the risk of ambulance dispatches. We initially identified 3628 peer-reviewed papers and included 48 papers which satisfied the inclusion criteria. The meta-analyses showed that, for each 5 °C increase in mean temperature, the risk of ambulance dispatches for all causes and for cardiovascular diseases increased by 7% (95% confidence interval (CI): 5%, 10%) and 2% (95% CI: 1%, 3%), respectively, but not for respiratory diseases. The risk of ambulance dispatches increased by 6% (95% CI: 4%, 7%), 7% (95% CI: 5%, 9%), and 18% (95% CI: 12%, 23%) under low-intensity, severe, and extreme heatwaves, respectively. We observed two potential sources of bias in the existing literature: (1) bias in temperature exposure measurement; and (2) bias in the ascertainment of ambulance dispatch causes. This review suggests that heat exposure is associated with an increased risk of ambulance dispatches, and there is a dose-response relationship between heatwave intensity and the risk of ambulance dispatches. For future studies assessing the heat-ambulance association, we recommend that (1) using data on spatially refined gridded temperature that is either very well interpolated or derived from satellite imaging may be an alternative to reduce exposure measurement bias; and (2) linking ambulance data with hospital admission data can be useful to improve health outcome classification.

Does increased core temperature alter cognitive performance during exercise-induced heat strain? A narrative review.

Research to date provides equivocal evidence regarding the influence of heat stress, heat strain, and more specifically, elevated exercise-induced core temperature on cognitive performance. This review sought to identify differences in how specific cognitive tasks were affected by increases in core body temperatures. Included papers (n = 31) measured cognitive performance and core temperature during exercise, while experiencing heightened thermal stress. Cognitive tasks were classified as cognitive inhibition, working memory, or cognitive flexibility tasks. Independently, core temperature changes were not sufficient predictors of cognitive performance. However, reaction time, memory recall, and Stroop tasks appeared to be most effective at identifying cognitive changes during heightened thermal strain. Alterations in performance were more likely to arise under increased thermal loads, which were typically associated with cumulative physiological stressors, such as elevated core temperatures, occurring alongside dehydration, and prolonged exercise durations. Future experimental designs should consider the relevance, or futility of assessing cognitive performance in activities that do not elicit a considerable degree of heat strain, or physiological load.

A cost-consequences analysis of the SAFE trial: a comparative, effectiveness trial evaluating high- versus low-supervision of an exercise intervention for women with breast cancer.

PURPOSE: The aim of this analysis was to compare the cost-consequences of a 12 week exercise intervention when delivered under high- versus low-level supervision conditions by an Exercise Professional (ExP) to women with breast cancer. METHODS: 60 women (50 ± 9 years) with stage II + breast cancer, who were insufficiently active, and reported ≥ 1 comorbidities or persistent treatment-related side-effects, were randomized to the high- or low-supervision group. The high-supervision group received 20 supervised sessions with an ExP over a 12 week period (reflecting a typical research model), whereas the low-supervision group received five sessions over the same period (replicating what is publicly funded within Australia). Health outcomes including health-related quality of life, and physical and psychosocial outcomes were assessed at baseline and post-intervention. To assess intervention consequences, composite effectiveness scores were created by calculating mean z-scores from raw data for all outcomes per participant. Total program costs were calculated including program development, staff training, program implementation, and equipment. RESULTS: 79.3% of the high- and 63.0% of the low-supervision group showed clinically relevant health improvements. Cost per improver was $1,814 for 23 improvers and $1,571 for 17 improvers in the high- and low-supervision groups, respectively. CONCLUSION: The SAFE exercise intervention, when delivered via high- or low-supervised conditions, represents good value with over 60% of women in both groups reporting health improvements. High-supervision levels resulted in a greater proportion of women experiencing health benefits, but future research will need to determine the longer term health impacts of these group differences.