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Survive the heat: Use proper hydration and work/rest cycles to battle the elements

It’s the middle of July and it is probably safe to say that most of us are really feeling the heat. What used to be bearable is now unbearable or, if you can stand a little heat, you are probably at least moving a little slower and getting tired faster. It is amazing how great the impact of the sun and heat has on the human body. It also makes me wonder what August may bring.

When it comes to everyday survival, a healthy respect of the sun has to be in place in order to stay in the best physical (and mental) health possible. If there were to be a major disaster, this becomes even more important as the typical systems of support, à la electricity and air conditioning that are typically used to help regulate body temperature and comfort, may not be available.

So why the focus on hydration and avoiding overworking? Simple, if you don’t pay attention you’ll become ill at best and the worse case scenario is death. Water keeps the body working, and a lack of water will start to shut the body down until it stops working all together.

Wet Bulb Globe Temperature (WBGT)

The wet bulb globe temperature is defined by the National Weather Service as the, “measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation).” Basically, the WBGT provides a better idea of how the elements will have an effect on your body and how to balance work with rest and how much water to consume at set intervals to maintain peak health and performance.

While there are many specialized WBGT thermometers that can be purchased, the WBGT information for a local area can be accessed through the National Weather Service (NWS). In the event of a large-scale disaster and information is not available locally from the NWS then it will be a necessity to possess a wet bulb thermometer.

Work/Rest cycles

The U.S. Army standards for water consumption are based on the Wet Bulb Globe Temperature and the type of work being performed. Types of work are:

Easy Work

  • Weapon Maintenance
  • Walking Hard Surface at 2.5 MPH, Less than 30 Pound Load
  • Marksmanship Training
  • Drill and Ceremony
  • Manual of Arms

Moderate Work

  • Walking Loose Sand at 2.5 MPH, No Load
  • Walking Hard Surface at 3.5 MPH, Less than 40 Pound Load
  • Calisthenic Exercise
  • Foot Patrolling
  • Individual Movement Techniques, i.e., High Crawl/Low Crawl
  • Constructing a Defensive Position

Hard Work

  • Walking Hard Surface at 3.5 MPH, greater than 40 Pound Load
  • Walking Loose Sand at 2.5 MPH With Load
  • Field Assaults

The heat categories

  • 1 (White) 78° – 81.9° WBGT
  • 2 (Green) 82° – 84.9° WBGT
  • 3 (Yellow) 85° – 87.9° WBGT
  • 4 (Red) 88° – 89.9° WBGT
  • 5 (Black) Over 90° WBGT

Based on the type of work and heat category as outlined above, the work/rest cycles are:

Heat Category 1

  • Easy Work (No Limit)
  • Moderate Work (No Limit)
  • Hard Work (40 Min. Work/20 Min. Rest)

Heat Category 2

  • Easy Work (No Limit)
  • Moderate Work (50 Min. Work/10 Min. Rest)
  • Hard Work (30 Min. Work/30 Min. Rest)

Heat Category 3

  • Easy Work (No Limit)
  • Moderate Work (40 Min. Work/20 Min. Rest)
  • Hard Work (30 Min. Work/30 Min. Rest)

Heat Category 4

  • Easy Work (No Limit)
  • Moderate Work (30 Min. Work/30 Min. Rest)
  • Hard Work (20 Min. Work/40 Min. Rest)

Heat Category 5

  • Easy Work (50 Min. Work/10 Min. Rest)
  • Moderate Work (20 Min. Work/40 Min. Rest)
  • Hard Work (10 Min. Work/50 Min. Rest)

The need to maintain a balance between work and rest ensures that water consumption aligns with water loss and the threat of injury or death from dehydration is minimized. Whenever possible, rest times should be observed in shaded areas and involve as minimal activity as possible.

Without a WBGT thermometer, the following guidelines can be used for work/rest cycles:

Easy Work

  • Continuous (86° or Less)
  • 75% Work/25% Rest (87° or Less)
  • 50% Work/50% Rest (89° or Less)
  • 25% Work/75% Rest (90° or Less)

Moderate Work

  • Continuous (80° or Less)
  • 75% Work/25% Rest (82° or Less)
  • 50% Work/50% Rest (85° or Less)
  • 25% Work/75% Rest (88° or Less)

Hard Work

  • Continuous (77° or Less)
  • 75% Work/25% Rest (78° or Less)
  • 50% Work/50% Rest (82° or Less)
  • 25% Work/75% Rest (86° or Less)

Water Consumption

Even during the fairest of weather, everyone loses water from breathing, sweating and our “bodily functions.” When temperatures increase, this fluid loss becomes even greater.

The gold standard for liquid consumption is water, but there are other ways to maintain hydration as well. All liquids will help with hydration, and the best thing to consider when choosing what to drink is how the content of the beverage and how it contributes to your overall health. It is worth noting that water intake can come from food as well as beverages. This makes a balanced diet that includes fruits and vegetables all the more important.

So how much water should you drink in a given day? The answer of course is that it depends.

The water consumption standards are as follows:

Heat Category 1

  • Easy Work: ½ Quart/Hour
  • Moderate Work: ¾ Quart/Hour
  • Hard Work: ¾ Quart/Hour

Heat Category 2

  • Easy Work: ½ Quart/Hour
  • Moderate Work: ¾ Quart/Hour
  • Hard Work: 1 Quart/Hour

Heat Category 3

  • Easy Work: ¾ Quart/Hour
  • Moderate Work: ¾ Quart/Hour
  • Hard Work: 1 Quart/Hour

Heat Category 4

  • Easy Work: ¾ Quart/Hour
  • Moderate Work: ¾ Quart/Hour
  • Hard Work: 1 Quart/Hour

Heat Category 5

  • Easy Work: 1 Quart/Hour
  • Moderate Work: 1 Quart/Hour
  • Hard Work: 1 Quart/Hour

It is imperative that individual water consumption does not exceed more than 1 ½ Quarts/Hour or 12 Quarts/Day. Exceeding these consumption limits can lead to illness and/or death from water intoxication (also known as water poisoning or over hydration).

Two of the self-monitored signs and symptoms of proper hydration include:

  • Urine Color (Clear or Pale Yellow)
  • Soft Bowel Movements

Signs and symptoms of improper hydration include:

  • Thirst
  • Less Frequent Urination
  • Dark-Colored Urine
  • Fatigue
  • Dizziness
  • Headache
  • Confusion
  • Vomiting
  • Diarrhea
  • Less Active Than Usual

While these signs and symptoms can be helpful in measuring hydration status, not everyone will feel the same way in the same circumstances. As an example, it is more common in older people for feelings of thirst to come on after the person has already started to become dehydrated.

To dispel a popular myth about hydration and caffeine, it is 100 percent not true that drinks that contain caffeine like coffee, tea and soda cause dehydration. In fact, people who consume moderate amounts of caffeine are known to stay equally hydrated as though who do not consume any caffeine at all.

When special circumstances are present like pregnancy, breastfeeding or illness (cold, flu, etc.), it may be important to consume slightly more water to try to maintain or recover your health.

Time of day

It is best to consider completing strenuous activities during the early morning hours or late in the evening when the temperatures are cooler and the sun is not directly beating down on you. If work needs to be done during the hours of the day that have peak heat, attempt to work with the weather and take advantage of cooler days or periods of cloud cover. It may even be beneficial to wait until it rains so that temperatures may drop. Rain can be tricky though because it can also lead to high levels of humidity.

Other risk factors

There are other factors aside from hydration that can make survival in the heat more difficult. While there are always exceptions to the rule, some of the factors that create a more dangerous situation by contributing to dehydration include:

  • Age — Young or Older
  • Weight — Under or Overweight
  • Physical Fitness — Poor Conditioning
  • Acclimatization — Being Used to the Area
  • Poor Metabolism
  • Alcohol or Drug Use
  • Some Prescribed Medications
  • Certain Medical Conditions

While an ideal set of circumstances would ensure that dehydration was never a concern, even during periods of time that result in restricted access to drinkable water can be better managed by having the information needed to successfully balance work and rest with the amount of available water to prevent injury, illness or death.

— Tom Miller

The post Survive the heat: Use proper hydration and work/rest cycles to battle the elements appeared first on Personal Liberty®.

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