keeping hydrated...

cycling_simon

okay... so i am doing my Alevel Product Design Course at the min and i am studying Camelbaks.

i want to know what are the affects of using a camelbak.

how long can you go before dehydration kicks in if you dont drink?

if you cycle for 30mins with and without drink what will the affects be on distance, and how you feel during and after?

any coments would be most helpfull

please help!

thanks

simon

MarvintheAndroid

Under normal conditions you need between half and one litre per hour. How quickly this kicks in is difficult to say, because it depends how well hydrated you were to begin with, how hot it is, how much you weigh, how hard you are working etc. However a good mouthful every 10 minutes or so is probably a reasonable guide.

Having said that the effects are cumulative and over a half hour period you wouldn't suffer much unless it was very hot.

For longer rides, many riders mix energy drinks instead of plain water.

BTW dehydration not only affects the bodys stamina, it also affects concentration, vision, etc which are often overlooked.

Don't forget the other features of Camelbaks, I also use mine to carry car keys, spare inner tube, tube repair kit, multitool, first aid pouch, wet weather top, spare front light, spare batteries and whistle. My pump is also attached to the side with sewn-on velcro straps.

Marv

Cajun

Supplementing the above reply, Temperature, humidity and energy expended are big factors to your answer also. I ride with a Camelbak because I hydrate more often than from the bottle, plus when on a long, hot climb, it's easier for me to hydrate than taking my hand off the bar. I've also survived some nice crashes by (happily) landing on my back with feet & bike pointing to the heavens...sure made a nice 'safety pad':). I believe the general rule-of-thumb is: Consume a 24oz bottle/hour of riding; more if the heat & humidity are a factor. We all differ; I ride with some females that drink ~8oz/hour (if that much) and they can do a Century on 2x24oz bottles without issues.

http://www.cptips.com/fluids.htm

Below is an excerpt from "Nutrition for Endurance" by Dr. Bill Misner:

Getting the right amount of water
On the average, an athlete loses a liter of fluid/hour of exercise. These perspiration-loss rates may be controlled or lessened by acclimation and training. The human body, when fit, will store enough muscle glycogen to provide energy for approximately 90 minutes of aerobic exercise. This extra glycogen storage through training helps balance the hydration equation. As muscle glycogen is burned to create energy for movement, water is released within the cells as metabolic by-product and is diverted to cool the body through skin-surface sweat.

Shepherd and Kavanagh (1978) found that during a marathon, competing runners released an average of 2 liters of perspiration through the process of burning muscle glycogen stores. If an athlete supplements this glycogen water by taking in 16 ounces of fluids for every hour of exercise, dehydration will normally be avoided in those events which last from three to four hours.

Researchers, however, have recently noted the dangers of too much hydration during events lasting over four hours. Noadkes (1985, 1988) reported that runners who drank too much during ultra-marathons and triathlons developed hyponatremeia (low blood serum). Hyponatremia, it turns out, may be caused by drinking too little or too much.

In ultra events, it is typically the front runners who dehydrate; those in the back of the pack tend to over-hydrate. Both suffer from the same hyponatremic symptoms – one from too little fluid intake and too much sodium loss due to profuse sweating; the other from too much fluid intake with proportionately less sodium loss.

Of the 17 runners who were hospitalized from after the 1985 Comrades ultra-marathon, nine had hyponatremia caused by diluting blood sodium levels with too much water. The tendency to linger at aid stations in a vain attempt to relieve the symptoms of fatigue or heat by drinking too much water is a fault found primarily in the runners who populate the back of the pack (Noakes 1990).

Overcoming the Heat
Air temperature and humidity are factors for overcoming heat related stress that one must consider along with fitness and acclimatization. When external temperature and humidity both exceed 70%-degrees, or when either temperature or humidity exceeds 80%-degrees, an athlete may do better to slow down his/her pace, expose as much skin as possible to cooling breezes, and take frequent walk breaks.

Increased body mass also increases metabolic heat production. A 100kg runner puts out twice the heat of a 50kg runner. No wonder the smaller, thinner runners tend to do better in the heat, year after year.

What replacement fluids should contain
Body fluid losses include both water and electrolytes. Electrolytes are chemical substances which, when dissolved in the water within the body or lost in our perspiration, are the missing electrically-charged particles, or ions, necessary for cellular metabolism. They help the body’s intra-/extra- cellular chemical balance and assist in the neuro-metabolic expenditure of caloric energy.

Athletes who are more fit and more acclimatized to heat lose less fluids and electrolytes. The rate of loss through sweat for a fit marathon runner includes a sodium loss of 2,000mg in that liter of fluid lost each hour (2kg/liter/hour). The average American athlete stores an excess of 8,000mg of dietary sodium within body tissues.

Losses per 1 hour of exercise:
Electrolyte: Fit/Acclimatized Athlete Unfit/Unacclimatized Athelete
Sodium 1800mg 3,500mg
Chloride 900mg 1,400mg
Potassium 100mg 200mg
Magnesium 100mg 100mg
Water 1.0 liter 1.0 liter

When one considers the possible losses during a 4-hour competitive event, it becomes obvious that maintenance of a balanced electrolyte supplement and moderate amounts of liquid are absolutely necessary both for survival and optimal performance in the heat.

Dose Recommendations per hour for beyond a three-hour performance
Calcium 250 to 500 mg
L-tyrosine 50 to 100 mg
Magnesium 125 to 250 mg
Manganese 5 to 20 mg
Potassium 99 to 198 mg
Pyridoxine HCL (B-6) 20 to 40 mg
Other formulations worth your consideration would increase sodium levels, if not raised to the point where they become problematic and cause negative side effects, more sodium may serve to assist electrolyte depletion and performance depletion in hyperthermic circumstances.