Understanding the risks involved in training in hot climates (25 °C+) and high humidity

The average temperature in September in Bahrain is 34 °C with a average humidity of 54%. Even in the evening at the start of the month the temperature is 35°C and humidity of 57%.

Do you think it’s safe to train???

• Deaths of three soldiers down to a catalogue of 'gross failures’…… their inquest concluded. Running on one of the hottest days of the year, with temperatures reaching more than 31 °C. Independent (2015)

Special Forces Selection

• Royal Marine dies on training exercise, the temperature in the Brecon Beacons would have been in the low to mid 20 °C s on Monday. He added: “It would have been a hot day, particularly on the low ground.” WalesOnline (2008)

• London marathon runner died yards from finish after his body overheated (2014): 23 °C

Robert Berry (42), who collapsed at the finish of the London marathon 2014 from a heat related injury. 

How heat affects your body

Training in hot weather (over 25 °C) puts extra stress on your body. If you don't take care when exercising in the heat, you risk serious illness.   When you training in the heat your body sends more blood to circulate through your skin. This leaves less blood for your muscles (reduction in oxygen), which in turn increases your heart rate. If the humidity also is high, your body faces added stress because sweat doesn't readily evaporate from your skin. That pushes your body temperature even higher.  Both the exercise itself and the air temperature and humidity can increase your core body temperature.

Under normal conditions, your skin, blood vessels and perspiration level adjust to the heat. But these natural cooling systems may fail if you're exposed to high temperatures and humidity for too long, you sweat heavily, and you don't drink enough fluids.

This can expose you to a range of Heat illnesses including:

• Heat cramps: are painful muscle contractions that can occur with exercise. You may feel muscle pain or spasms. Your body temperature may be normal.

• Heat syncope and exercise-associated collapse Exercise-associated collapse is feeling lightheaded or fainting immediately after exercising, and it can occur especially if you immediately stop

• Heat exhaustion. Your body temperature rises as high as 40 C, and you may experience nausea, vomiting, weakness, headache, fainting, sweating and cold, clammy skin. If left untreated, heat exhaustion can lead to heatstroke.

• Heatstroke. life-threatening emergency condition that occurs when your body temperature is greater than 40 C. Your skin may be dry from lack of sweat, or it may be moist. You may develop confusion, irritability, headache, heart rhythm problems, dizziness, fainting, nausea, vomiting, visual problems and fatigue. You need immediate medical attention to prevent brain damage, organ failure or even death.

If you ignore these symptoms, your condition can worsen, resulting in a medical emergency. Signs and symptoms may include:

• Muscle cramps

• Nausea or vomiting

• Weakness

• Fatigue

• Headache

• Excessive sweating

• Dizziness or lightheadedness

• Confusion

• Irritability

• Low blood pressure

• Increased heart rate

• Visual problems

If you develop any of these symptoms, stop exercising immediately, get out of the heat and lower your body temperature. Ignoring these symptoms, your condition can worsen, resulting in a medical emergency.

If you've had heatstroke. Your doctor will likely recommend that you wait to return to exercise or sports until you're not experiencing symptoms. You may require many weeks before you are able to exercise at a high level.

How to avoid heat-related illnesses

When you exercise in hot weather, keep these precautions in mind:

• Watch the temperature

• Get acclimated. Remember: You won’t get acclimatised spending 23 hours in Air conditioned environment and an hour outside

• Know your fitness level. If you're unfit or new to exercise, be extra cautious 

• Drink plenty of fluids. Dehydration is a key factor in heat illness

• Dress appropriately. Lightweight, loose fitting clothing helps sweat evaporate and keeps you cooler. Avoid dark colours

• Have a backup plan. If you're concerned about the heat or humidity, stay indoors.

• Understand your medical risks. Certain medical conditions or medications can increase your risk of a heat-related illness. If you plan to exercise in the heat, talk to your doctor about precautions.

Basically, the hotter it is and the higher the percentage of relative humidity, the riskier it is to work out. The National Weather Service has a Heat Index Chart that you can use to tell how hot it feels relative to humidity and temperature. 

Heat Index: Used by the UK Military to assess risk of Heat related injuries

For example, if the temperature is 31C, and the relative humidity is 85%, you can look at the chart and determine that it'll feel like it's 43 degrees out. The heat index chart also clearly lays out at what point you need to be worried about heat-related illnesses (it's broken down into: caution, extreme caution, danger, and extreme danger).

So with an outside evening temperature of 35°C and humidity of 57%., on the Heat Index Chart, it feels like 44 °C and is clearly in the higher end of DANGEROUS.

This is like be the case in Bahrain throughout September and October due to the high temperature and humidity at this time of year.

Training in this level of heat and humidity outside is dangerous with the risk to your health far outweighing the benefit.

My professional advice if your planning on doing high intensity training outside like interval training, running or circuits….DON’T!

Train in an environment that allows you to train at the right intensity until the weather cools and humidity drops. Find a coach is properly qualified, experienced and who understand the risks involved in training in extreme climates.