Heat Stroke and Sunstroke: Prevention

To prevent heat stroke and sunstroke, attention must be paid to reducing individual risk factors. Behavioral risk factors

  • Diet
    • Insufficient fluid and electrolyte intake (electrolyte deficiency), i.e. insufficient compensation of sweat losses.
  • Consumption of stimulants
    • Alcohol* (alcohol consumption is considered a risk factor for heat illness regardless of physical exertion).
  • Drug use (can trigger hyperthermia).
    • 3,4-Methylenedioxypyrovalerone (MDPV, “bath salts“).
    • Amphetamines (indirect sympathomimetic).
    • Cocaine
    • “magic mushrooms” (psilocybin)
    • Methylenedioxyamphetamine (Ecstasy)
    • Phenylcyclohexylpiperidine (PCP, “angel dust”).
  • Physical activity
    • Sports
    • Severe physical exertion under high ambient temperature and insufficient hydration → exercise-induced hyperthermia
    • No heat acclimatization*
    • Dehydration*
  • Sleep deprivation*
  • Overweight (BMI ≥ 25; obesity)* ; heat incident for:
    • Trained overweight: almost 4 times higher risk.
    • Untrained overweight recruits: 8-fold increased risk.
  • No head covering (i.e. sun exposure to uncovered skull → thermal meningitis/ meningitis).
  • Thermal insulating clothing
  • Prolonged standing in hot environment → see below symptoms/heat syncope.

Medications that can negatively affect thermoregulation or provoke desiccosis (dehydration):

  • Anticholinergics, antidepressants: increase heat production and thus increase body temperature, which leads to increased sweating and thus electrolyte losses!
  • Antihistamines
  • Benzodiazepines
  • Beta-blockers: reduction in cardiac output (cardiac output), which may affect heat adaptation.
  • Diuretics and ACE inhibitors/ angiotensin II receptor antagonists: dehydration (fluid deficiency) and/or electrolyte imbalance (imbalance of body salt balance) due to hyponatremia (sodium deficiency).
  • Neuroleptics, Selective Serotonin Reuptake Inhibitor (SSRI): inhibition of central thermoregulation.
  • Muscarinic receptor antagonists: reduction of sweat secretion and thus risk of overheating.
  • Sedation by dopaminergic and Parkinson’s drugs: lowering the perception of heat exhaustion or reducing the feeling of thirst and thus risk of dehydration.

Environmental stress – intoxications

  • High ambient temperature*
    • Heat (heat day: > 30 °C; desert day: > 35 °C)Note: Above 37 degrees it can be critical for humans, especially if it is humid.
  • High humidity*
  • Lack of air movement*
  • Lack of shadow*

* Risk factors of exertion-induced heat stroke.

Prevention measures in the heat

  • Nutrition
    • Attention should be paid to an adequate amount of drinking (eg, high-sodium mineral water, isotonic sports drinks or fruit juice spritzers in a ratio of 3/4 to 2/ 3 water to 1/4 to 1/3 juice).
    • As far as no diseases (eg heart failure / cardiac insufficiency) limit the fluid requirement – per kilogram of body weight 35 ml (from the age of 65: 30 ml) of water per day; in case of heavy sweating, the drinking amount increases to more than 3 liters / day; to note, only if the urine is light, the fluid intake is sufficient!
    • In very hot weather, water with a sodium content of 400-800 mg / l should be drunk; if necessary, high-salt diet or taking salt tablets in heat-exposed persons; also a sufficient supply of magnesium and potassium is required – after several hours of continuous exercise about 300 mg potassium / liter are lost through sweat.
    • Abstain from alcohol and drugs!
  • Clothing
    • When outdoors, headgear should always be worn.
    • Lightweight, air-permeable clothing should be worn, rather than tight-fitting clothing.
    • The clothing should be as light as possible, so as not to put additional stress on the body by stored heat…
    • Sunglasses with optimal UV protection (UV400) should always be worn; these block all UV rays below 400 nm (UV-A, -B, -C).
  • Physical activity
    • Before heavy exertion, the body should be accustomed to the new climate (sufficient acclimatization).
    • Heat acclimatization (heat acclimatization) occurs only through physical activity and lasts about 4 to 5 days.
    • For training, use the cool morning hours or the evening hours.
    • Limit physical activities when the temperature in the shade is high.
    • Already from 28 ° C can lead to circulatory problems, sunstroke, heat stroke or dehydration (dehydration) during strenuous exercise (especially endurance sports).
    • At a humidity of more than 80% or ozone values of more than 180 μg/m3 air is to refrain from an intensive running training.
    • Recreational activities only to the extent that these, taking into account air temperature, humidity and air movement, do not lead to physical overload!
    • In high temperatures, the last meal before a sporting activity should be at least two hours ago.
    • For endurance sports, start with a maximum of 30 to 40 minutes at reduced intensity; heart rate should not be more than 10 beats higher than normal.
  • Body care and cooling down
    • Frequent cold showers without detergent or detergent (to prevent sebum depletion); if necessary, it may be sufficient to hold the arms up to the elbows in cold water or refresh the calves by treading water in a bucket of cool water.
  • Pay attention to blood pressure!
    • This note applies to patients taking antihypertensive drugs. If the blood pressure is strikingly low despite sufficient fluid intake, contact should be made with the family doctor. The question should be clarified whether not given if the dose of blood pressure medication should be temporarily reduced.
  • Medication: some drugs can negatively affect thermoregulation or provoke exsiccosis (dehydration):
    • Anticholinergics, antidepressants: increase heat production and thus increase body temperature, which leads to increased sweating and thus also to electrolyte losses!
    • Beta-blockers: reduction of cardiac output (cardiac output), which may affect heat adaptation.
    • Diuretics and ACE inhibitors/ angiotensin II receptor antagonists: dehydration (fluid deficiency) and/or electrolyte imbalance (imbalance of body salts) due to hyponatremia (sodium deficiency).
    • Neuroleptics, Selective Serotonin Reuptake Inhibitors (SSRIs): inhibition of central thermoregulation.
    • Muscarinic receptor antagonists: reduction of sweat secretion and thus risk of overheating.
    • Sedation by dopaminergic and Parkinson’s drugs: lowering the perception of heat exhaustion or reducing the feeling of thirst and thus risk of dehydration.
    • The State Health Office in Lower Saxony (NLGA) points to risks from other drugs. These include non-steroidal anti-inflammatory drugs (NSAIDs), antiarrhythmics, biguanides, H1 antihistamines, pseudoephedrine, sulfonamides and sulfonylureas.
    • Notice:
      • Dehydration can lead to increased toxicity of drug concentrations in the body (e.g., lithium).
      • Transdermal systems (e.g., fentanyl patches) may result in increased drug release, leading to overdose….

    Travel advice: when traveling in countries with hot or hot and humid climate, a consultation regarding the intake of medication is required!