When you live in the desert you realize how important hydration is to perform well on you outdoor adventures. Also performing your outdoor adventures becomes quite challenging if you are not willing to “hibernate” in your AC cooled “cave” in Dubai during the warmest months. As opposed to that, performing your favorite sports under very cold conditions is another joy many would refuse to take unless they know for sure they can return to their comfort zone right away. That is the secret recipe of successful businesses likeSki Dubai, the first indoor ski resort in the Middle East and largest indoor snow park in the World, where people can enjoy freezing temperatures and going back home on the same day through the sandy roads of UAE. Staying hydrated under extremely cold conditions is also crucial and surprisingly difficult if you don’t have the right experience and gear.
For some people like me, learning how to stay out of the comfort zone and performing well for long periods time is crucial in order to achieve our goals, such us climbing the highest mountains in the World. For the last two years I’ve been training regularly outdoors and practicing my adventure sports even when the temperature goes over 40°C and 80% humidity. I’ve been also jumping for these hellish temperatures to subzero conditions in just few hours or days. During all that time I have heard many stories and learned many lessons on the way…
Feel likes temperatures
Many times when you watch the weather forecast or you read it in you mobile phone app, you hear about the Feels Like Index, which normally differs from the actual temperature one can expect to see in the display of your adventure watch. This is a factored mixture of the Wind Chill Factor and the Heat Index.
Wind Chill Factoris the apparent temperature felt on exposed skin, which is a function of the air temperature and wind speed. It is always lower than the air temperature, except at higher temperatures where wind chill is considered less important. In cases where the apparent temperature is higher than the air temperature, the heat index is used instead.
The Heat Indexcombines air temperature and dew point in an attempt to determine the human-perceived equivalent temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries heat away from the body. However, when the relative humidity is high the evaporation rate is reduced, so heat is removed from the body at a lower rate causing it to retain more heat than it would in dry air. Measurements have been taken based on subjective descriptions of how hot subjects feel for a given temperature and humidity, allowing an index to be made which corresponds a temperature and humidity combination to a higher temperature in dry air.
At high temperatures, the level of relative humidity needed to make the heat index higher than the actual temperature is lower than at cooler temperatures. For example, at 27°C the heat index will agree with the actual temperature if the relative humidity is 45%, but at 43°C, any relative-humidity reading above 17% will make the Heat Index higher than 43°C. Humidity is deemed not to raise the apparent temperature at all if the actual temperature is below approximately 20°C.
Heat index is based on temperature measurements taken in the shade and not the sun, so extra care must be taken while in the sun.
Training in Dubai, day or night?
Solar radiation can be extreme if there is little humidity to block the sun’s rays. Desert surfaces receive more than twice the solar radiation received by humid regions and lose almost twice as much heat at night. During the summer the temperature in the desert goes to extreme values and the warm air is captured in humid coastal areas like the city of Dubai, where relative humidity levels normally reach the maximum around 12am. At the same time inland desert areas cool down dramatically since the dry air does not capture the heat.
According to this, the heat index in Dubai is problematic during both night and day times. And solar radiation hardens the conditions during the day. Both heat index and solar radiation are not an issue at night in desert areas away from the coast. Therefore the ideal training scenario is located somewhere in the desert sometime during the night.
If you have to train in the city like I do most of the time, you should consider doing it in the evening after the sunset, and before or after the maximum humidity levels are reached. I normally use wunderground.comto observe these values through the year.
The benefits of training in extreme heat
Failing to prepare properly for training in the warmer months in Dubai can lead to the following:
- Training during the day can lead to Sun stroke (AKA Insolation, Thermic Fever or Siriasis), term applied to the effects produced upon the central nervous system, and through it upon other organs of the body, by exposure to the sun.
- Training during the night can lead to Heat stroke, which is a form of hyperthermia, an abnormally elevated body temperature with accompanying physical and neurological symptoms.
However, when approached correctly, training under warm conditions has its benefits and is known as heat acclimatization training.
According to a study published by Aoyagi, McLellan, and Shephard, the potential benefits of heat acclimatization training are:
(i) improved aerobic fitness and thus a greater cardiovascular reserve (probably seen mainly after training)
(ii) a lower resting body temperature that allows greater heat storage (probably seen mainly after acclimation)
(iii) a decreased energy cost of a given intensity of exercise (seen after acclimation and also as the learning component of training)
(iv) an enhanced sweating response at a given percentage of maximal effort (probably developed by both treatments)
(v) a slower increase in body temperature owing to (iii) and/or (iv) [seen after both treatments]
(vi) a reduced cardiovascular stress because of changes in the autonomic nervous system (probably realized mainly by training), expansion of blood volume (seen after both treatments) and/or a decreased peripheral pooling of blood (probably found after both treatments)
(vii) improved subjective tolerance reflecting a decrease in the relative intensity of a given activity (probably seen mainly after training), a reduction in the physiological strain (found after both treatments) and/or habituation to heat-exercise stress (probably developed by both treatments)
Factors affecting improvements in physiological and psychological responses to a given set of conditions include:
(i) the individual’s initial fitness and acclimatization to heat
(ii) age, gender, hydration, sleep deprivation, circadian rhythms and in women the menstrual cycle
(iii) use of ergogenic aids such as fluid ingestion, carbohydrate and/or electrolyte replacement and blood doping;
(iv) event or test conditions such as the mode of exercise, the severity of environmental heat stress and the type of clothing worn
(v) treatment conditions such as the intensity, duration and frequency of exercise and/or heat exposure, the length of any rest intervals and cumulative depletion of body water and minerals
When training in high temperatures these are some factors to take into account
- There are certain times in a day when both the solar radiation and heat index are minimum. In Dubai I find perfect training around 9pm when solar radiation has been partially dissipated and heat index remains “low”
- Running long distance is not a good idea, since is very difficult to re-hydrate on the go. If you chose to train long distance, rather than intervals or speed, use a good hydration system to be carried in a backpack or belt
- Opt for the lightest clothing you can find and make sure it can handle the excess of sweat. Some fabrics like cotton tend to absorb and retain liquid preventing evaporation of sweat, thus leading to the risk of heat stroke. On some good training clothes made of synthetic fabrics you can easily see the sweat dripping from specifically designed areas, and when you finish the training session they dry out quickly and do not retain odor.
The importance of staying hydrated
Water makes up about 70 percent of the muscles, organs, and solid tissue in the body and is crucial to many of the body’s processes. Dehydration negatively affects such functions as eliminating toxins, delivering nutrients, carrying oxygen to the cells of the body, producing energy, and lubricating joints. Dehydration can impact proper balance of vital electrolytes, such as sodium and potassium, which are also essential to healthy functioning of the body.
The body normally generates heat as a result of metabolism, and is usually able to dissipate the heat by either radiation of heat through the skin or by evaporation of sweat. However, in extreme heat + high humidity + vigorous physical exertion, the body may not be able to dissipate the heat and the body temperature rises, sometimes up to 41°C or higher. The main cause of heat stroke is dehydration. A dehydrated person may not be able to sweat fast enough to dissipate heat, which causes the body temperature to rise.
There are different methods to diagnose dehydration, such as a complete blood count or urine specific gravity tests. But when we are up in the mountains the only and best method is using common sense, and thirst is the first indicator of dehydration. A properly hydrated climber drinks small amounts of water constantly so that thirst do not manifest as symptom of dehydration state. Other indicators are dry mouth, decreased urine output and increased urine osmolality (concentration of particles in urine), dry skin, headache (especially in the morning) or constipation. I personally pay extra attention to the color or my urine. Lightly colored urine is produced under normal hydration (euhydration). Completely clear urine indicates hyperhydration, which might become an issue in high altitude especially for people prone to develop AMS (Acute Mountain Sickness). Too little and highly colored urine reveals hypohydration (dehydration).
At high altitude it is normal to be urinating more than usual. That is due to some changes taking place in the body’s chemistry and fluid balance during acclimatization. The osmotic center, which detects the “concentration” of the blood, gets reset so that the blood is more concentrated. This results in an altitude diuresis as the kidneys excrete more fluid.
If you are not taking a leak frequently during your ascent, it’s a clear indicator you may be dehydrated, or you may not be acclimatizing well. The most effective solution for the latter is the treatment with acetazolamide (Diamox®). This is a medication that forces the kidneys to excrete bicarbonate, triggering some effects that will help on acclimation and fighting AMS. Since acetazolamide works by forcing a bicarbonate diuresis, you will urinate more on this medication.
At extreme altitudes the digestive system becomes inefficient, and it’s crucial to get rid of the toxins, therefore we should pay extra attention to visit the loo to make water and all the rest regularly. A proper hydration will facilitate the formation and displacement of sediments in the intestines.
Dehydration at high altitude and subzero conditions
Many people confuse the symptoms of dehydration with altitude sickness, but at moderately high altitudes dehydration is responsible for more illness than oxygen insufficiency.
There are different reasons why people dehydrate faster at high altitude. With lower pressure, moisture from skin surface and lungs evaporates faster, sun and wind exposure is also higher, accelerating evaporation. Relative humidity is generally low at high altitude, which facilitates perspiration during periods of intense physical activity. With lower oxygen levels, breathing patterns change and bigger amounts of moist are exhaled.
And there are many factors that make rehydration difficult at high altitude. Water sources are generally limited and they have to be transformed from solid states and treated to prevent illness. As a rule of thumb during my expeditions I never drink water from springs or rivers. On short trips the presence of virus or parasites in the water is not a big point of concern, but when I’m embarked in a long and demanding expedition I always take the precaution of filtering and purifying drinking water. Once the water is prepared, it has be stored and carried up the hill. In certain situation this becomes sort of a challenge. During alpine ascents the amount of gear carried up the hill has to be reduced to the bare minimum and sometimes we have to restrict the amount of bottled water we take with us. Also we have to be precise with the amount of fuel to transport since this will determine the amount of water we can prepare throughout the ascent. Under very cold weather conditions, preventing the water from freezing is also very challenging. Many times we find ourselves with plenty of solid water stored in our heavy backpack, that has become totally useless, and we can’t even get rid of it! To sum one more difficulty to the process of being hydrated, it worth mentioning that many people do not feel as thirsty in higher altitudes as they should. Besides that, we are normally busy with the technical aspects of the ascent, therefore we cannot get easy access to our water bottles, we tend to forget about drinking, and we dehydrate unconsciously.
In future posts I will go through some tips & tricks I use in my expeditions to process, disinfect and transport water. I will also explain which products can be used to improve the water characteristics, helping keep body chemistry in balance and accelerating recovery.