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Saturday, July 01, 2006

Why Hydrate

hydrateTo perform at the peak of your athletic ability, proper hydration is of the utmost importance. During exercise, your heart increases the blood flow to the muscles (in use) and the skin (to cool your body down). Through perspiration, your body loses about 1-litre (32 oz) of water per hour based on moderate activity. If you don’t replace the water you lose, your body starts to become dehydrated. At a higher heart rate and core temperature, your body can’t produce more energy, leaving you weakened and much more vulnerable to heat illness (symptoms such as headaches, nausea and muscle fatigue)

The best defense against dehydration is a good offense – drink often – at least 1 litre (32 oz) per hour for moderate activity in moderate conditions. It’s also better to drink continuously – 6 to 8 oz every 15 to 20 minutes is recommended by the American College of Sports Medicine. Remember that thirst is a delayed response, and by the time you’re thirsty, your body is already dehydrated. Always carry some sort of .

For endurance athletes, the USA track and field advisory also suggests adding 700mg of sodium per litre (32 oz) of water. This, or the occasional salty or powerbar-type snack, will help prevent the onset of , a rare condition that occurs when the level of sodium in your blood gets dangerously low. This condition is rare but can occur after a full day of strenuous activity.

The USATF also suggests using hydration systems to help keep fluids cooler, making it easier for your body to absorb.

Dehydration can set in sooner than you think. You can easily lose 2 litres (64oz) / hour on a hard ride or a run on a hot day, but even recreation outdoors enthusiasts can lose up to 1 to 1.5 litres per hour. In a recent position statement of the National Athletic Trainers Association, as little as a 1 to 2 percent lose of fluids could negatively affect function and performance. A 1 to 2 percent loss of fluids can occur after a little more than one hour of moderate activity in cool weather without water. At 3 percent, the risk of potential heart illness increases exponentially.

Initial Dehydration
2% of body weight lost
3 lbs of fluid lost (1.5 litres)
Happens in about 1 hour
Decreased athletic performance, decreased muscular endurance

Heat Cramps
4-6% of body weight lost
6-9 pounds of fluid lost
Happens in about 2 to 3 hours
Muscle cramps, loss of strength, fatigue

Heat Exhaustion
6 to 8% of body weight lost
9 to 12 pounds of fluid lost
Happens in about 3 to 4 hours
Dizziness, serious fatigue, nausea, high temperature

Heat Stroke
7 to 8 % of body weight lost
11 – 12 pounds plus fluid lost
Happens in 4+ hours
Confusion, loss of consciousness

Rob's note: This article came to be because of a percieved need to make new participants of Warrior Camp aware of the need to be hydrated before attending camp.

Hyponatremia related articles:

Emergency Medicine: Hyponatremia


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Rob Coopers Fat burning tips In 1990 Rob weighed 475 pounds and was able to burn almost 300 lbs of fat in just two and a half years. Rob does weight management coaching from his office in Edmonton Alberta Canada. Rob's diet is based on a "System Specific Organic Whole Food" line of foods along with various fat burning, muscle building tips from Tom Venuto. Tom's Philosophy is very similar to Rob's and he's happy to recommend them

Rob is currently using the Seven Minute Muscle Workout program.


At 11:39 AM, Anonymous Anonymous said...

Given the heat of the summer, your post is a very timely and wise reminder regarding the importance of preventing dehydration, not just for those participating in activities but also for everyone and anyone. The elderly can be particularly susceptible because as we age we aren't as astute at feeling thirst or recognizing our needs for hydration. Thanks for the great post, and the reminder.



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