![\"\"](\"https:\/\/stg-blogs.bmj.com\/bjsm\/files\/2011\/03\/runners-over-bride_2.jpg\" "\\"runners")
<\/p>\n<\/p>\n
The packs of runners visible on many urban landscapes are a clear sign that distance road race season is upon us. As professional and amateur competitors get ready for their big events, lots of advice and suggestions are bouncing around the Internet. <\/em><\/p>\n One of the most common misconceptions is that athletes should over-hydrate before races to prevent illness. Don\u2019t do this — \u00a0drink according to thirst!<\/strong>…but I am getting ahead of myself here. In part 1 of this 2-part blog post let\u2019s turn to the expertise of BJSM Associate Editor Professor Tim Noakes:<\/em><\/p>\n Individual susceptibility, rather than the environmental conditions, plays a much more important role in the development of heatstroke than previously acknowledged.<\/p>\n Humans have remarkable ability to exercise in the heat without health risk. This was brilliantly shown by the performance of the 40 kg Japanese runner, Mizuki Noguchi<\/a>,<\/strong> who won the 2004 Athens Olympic Marathon for women in a time of 2 h 26 min 20 s despite the extreme environmental conditions\u201435\u00b0C with moderate humidity (watch<\/a><\/strong> video clip of race<\/a><\/strong>). However, heat injury, in particular heatstroke,can afflict persons exercising in much less severe environmental conditions when the total heat load cannot explain why heatstroke developed.<\/p>\n To prevent harm, it is important to be aware of the causes, presentation, and treatment of heatstroke and exercise-associated collapse and cramps.<\/p>\n Appropriate clinical assessment of the athlete who presents after exercising in the heat is the cornerstone of good management. In the past, there has been a tendency to initiate treatment before making a rational diagnosis. This position was taken partly because of the problem of high rates of admission to the medical tent at major events and partly because it was assumed<\/em> that all athletes who collapsed were dehydrated and needed immediate intravenous hydration. The former problem can be overcome by a system of triage at events, and the latter assumption is not evidence-based (Noakes 2000).<\/p>\n Thus, the emergency treatment of life-threatening conditions, including heatstroke and hyponatremia, can safely be delayed for 1 or 2 minutes while the rectal temperature and the blood sodium concentration are measured and a reasonable working diagnosis is established. The obvious exception is cardiac arrest, which occurs uncommonly, and the diagnosis of which is unambiguous.<\/p>\n How severe is the heat illness?<\/p>\n Conscious<\/strong><\/span><\/span><\/span><\/span><\/p>\n Alert<\/strong><\/span><\/span><\/span><\/span><\/p>\n Rectal temperature: <40\u00b0C (104\u00b0F)<\/strong><\/span><\/span><\/span><\/span><\/p>\n Systolic blood pressure: >100 mmHg<\/strong><\/span><\/span><\/span><\/span><\/p>\n Heart rate: <100 beats\/min<\/strong><\/span><\/span><\/span><\/span><\/td>\n Unconscious or altered mental state<\/strong><\/span><\/span><\/span><\/span><\/p>\n Confused, disoriented, aggressive<\/strong><\/span><\/span><\/span><\/span><\/p>\n Rectal temperature: >40\u00b0C (104\u00b0F)<\/strong><\/span><\/span><\/span><\/span><\/p>\n Systolic blood pressure: <100 mmHg<\/strong><\/span><\/span><\/span><\/span><\/p>\n Heart rate: >100 beats\/min<\/strong><\/span><\/span><\/span><\/span><\/td>\n<\/tr>\n Blood glucose level: 4\u201310 mmol\/L (72\u2013180 mg\/dL)<\/strong><\/span><\/span><\/span><\/span><\/p>\n Serum sodium concentration: 135\u2013148 mmol\/L Body weight loss: 0\u20135%<\/strong><\/span><\/span><\/span><\/span><\/p>\n <\/strong><\/span><\/span><\/span><\/span><\/td>\n Blood glucose level: <4 or >10 mmol\/L (<72 or Serum sodium concentration: <135 or >148 mmol\/L Body weight loss: >10%<\/strong><\/span><\/span><\/span><\/span><\/p>\n Body weight gain: >2%<\/strong><\/span><\/span><\/span><\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n <\/strong><\/p>\n Tomorrow we outline the top 10 recommendations for the prevention of heat illness<\/p>\n In related news, 9 Japanese women were added to the elite London Marathon field as their World Championship trial was cancelled because of the earthquake and tsunami. Read more <\/em>here<\/em><\/a><\/p>\n References: Noakes TD. Hyperthermia, hypothermia and problems of hydration. In: Shepard RJ, Astrand PO, editors.\u00a0Endurance in Sport<\/em>. Oxford: Blackwell Scientific, 2000:591-613.<\/p>\n","protected":false},"excerpt":{"rendered":" The packs of runners visible on many urban landscapes are a clear sign that distance road race season is upon us. As professional and amateur competitors get ready for their big events, lots of advice and suggestions are bouncing around the Internet. One of the most common misconceptions is that athletes should over-hydrate before races […]<\/p>\nGuidelines for determining the severity of the collapsed athlete\u2019s condition<\/strong><\/h3>\n
\n\n
\n Non-severe<\/strong><\/span><\/span><\/span> <\/strong><\/span><\/span><\/span><\/td>\n Severe<\/strong><\/span><\/span><\/span> <\/strong><\/span><\/span><\/span><\/td>\n<\/tr>\n \n I<\/strong><\/span>mmediate assessment<\/strong><\/span><\/span><\/span><\/p>\n Immediate assessment<\/strong><\/span><\/span><\/span><\/p>\n \n Specialized assessment<\/strong><\/span><\/span><\/span><\/p>\n
\n(135\u2013148 mEq\/L)<\/strong><\/span><\/span><\/span><\/span><\/p>\nSpecialized assessment<\/strong><\/span><\/span><\/span><\/p>\n
\n>180 mg\/dL)<\/strong><\/span><\/span><\/span><\/span><\/p>\n
\n(<135 or >148 mEq\/L)<\/strong><\/span><\/span><\/span><\/span><\/p>\n
\n<\/em><\/p>\n