More on fitness myths from outsideonline.com.
Myth #5: Dehydration hurts performance
Truth: Overhydrating is more likely to sabotage your personal record.
In the 1990s, endurance athletes were advised to stay ahead of their thirst and drink as much as they could stand during training and races. A decade later, almost everyone had been schooled with the knowledge that hydrating to excess can cause hyponatremia—essentially, intoxication caused by consuming too much water, a potentially fatal condition in which cells swell with the excess fluid.
However, whether dehydration is equally troublesome and a hindrance to peak performance remained up in the air. But according to a 2011 review of time-trial studies of dehydration, losing up to 4 percent of body weight during exercise does not alter performance. Results from endurance events seem to bear that out: during the 2009 Mont-Saint-Michel Marathon in France, researchers measured the weight loss of 643 competitors and compared it with their finish times. The runners who lost the most water weight were also the fastest. Most of those who finished in less than three hours lost at least 3 percent of their body weight to sweat.
Get over it: “Drink when you feel thirsty,” says James Winger, M.D., assistant professor at Loyola University’s Stritch School of Medicine in Chicago, who conducted a survey of distance runners last year and found that misconceptions about hydration were rampant, even among endurance athletes. “Thirst is an exquisitely finely tuned indicator of your body’s actual hydration status,” Dr. Winger says. “Listen to it.”
I feel I need to add a bit to this article. It is vital to stay hydrated during workouts and events- it is very easy to dehydrate, especially during intensive workout sessions or very hot outside events. As most doctors will tell you, there really isn’t a great way to determine your hydration levels. The way most experts tell you to monitor your hydration level is to monitor the colour of your urine. Very dark urine indicates dehydration; while light to clear urine shows adequate hydration. The Mayo Clinic offers these guidelines on dehydration symptoms:
Mild to moderate dehydration is likely to cause:
- Dry, sticky mouth
- Sleepiness or tiredness — children are likely to be less active than usual
- Decreased urine output — no wet diapers for three hours for infants and eight hours or more without urination for older children and teens
- Few or no tears when crying
- Dry skin
- Dizziness or lightheadedness
Severe dehydration, a medical emergency, can cause:
- Extreme thirst
- Extreme fussiness or sleepiness in infants and children; irritability and confusion in adults
- Very dry mouth, skin and mucous membranes
- Lack of sweating
- Little or no urination — any urine that is produced will be dark yellow or amber
- Sunken eyes
- Shriveled and dry skin that lacks elasticity and doesn’t “bounce back” when pinched into a fold
- In infants, sunken fontanels — the soft spots on the top of a baby’s head
- Low blood pressure
- Rapid heartbeat
- Rapid breathing
- No tears when crying
- In the most serious cases, delirium or unconsciousness