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Sweat with Hydration I

It is very important to know about the consumption of water, when to drink, how to drink and how much to drink. As manier times all of us are given different kinds of advice about consuming water while working out or exercising.

Water has a greater effect on athletic performance than any other nutrient. Water is the only nutrient that is lost during exercise in amounts several times greater than amounts lost from non-exercising individuals. The threshold for the induction of thirst occurs at a point where a person is already dehydrated to a level of 0.8% to 2% of body weight.

It is a coolant for working muscles. The working muscles generate heat which when degraded helps mountain normal body temperature (between 39°C and 41°C). SWEAT releases this heat and cools the body. The human body is not efficient at converting potential energy from oxygen and nutrients into mechanical energy. During exercise only about one fourth of this potential energy from oxygen and nutrients into mechanical energy, resulting in about 75% of the energy turnover generated as heat. Most of the heat generated by exercising muscle transfers to the blood circulating through the body and rising core temperature.

The amount of heat produced during exercise, even in physically fit individuals, is enough to raise core body temperatures by 1°C every 5 to 8 minutes. Without effective means to degrade this heat, moderate intensity exercise could raise body temperatures to lethal levels in 15 to 30 minutes. These events last for several hours and the body may produce rectal temperature in excess of 40.6°C. Under such conditions athletes may lose fluid conditions at rates of 2.0 to 2.8 liters per hour resulting in water deficit of 6-8% of body weight.

Each 1% body water loss causes; plasma volume decrease by 2.5%; muscle water decreases by 1% and rectal temperature increases by 0.4-0.5°C.

The body loses water via sweat. Breathing costs water too, exhaled as vapor. During physical activity, both routes are significant and dehydration becomes a threat. Dehydration’s first symptom is fatigue: a water loss of even 1 to 2% of body weight can reduce a person’s capacity to do muscular work. With a water loss of about 7% a person is likely to collapse.

Scientists define dehydration as fluid losses greater than just 1% of body weight. Loss of water causes decline in blood volume, increase in heart rate, a drop in blood pressure, an increase in body temperature.

Athletes need enough water to maintain the body’s ability to regulate its internal temperature and so keep itself cool. Most energy released during metabolism appears immediately as heat, unless this released heat is quickly degraded or may result in heat cramps,heat exhaustion or deadly heat stroke may ensure.

Depending on the intensity and duration of the training, one of the the things should be consumed during training;

Plain cool water- it is not an option for athletes, it is only for short bouts of training(less than one hour)or longer duration of low-intensity activity. For light weight training or cardiovascular training.

Electrolytes (ORS or Oral Rehydration Solution)- isotonic in electrolytes with 1-2% glucose- for rehydration, for intense training of limited duration (upto 60-90 minutes). It is for intense weight training or cardiovascular training.

Sports drink- 6-8% glucose/other carbohydrate with electrolytes and vitamins- for endurance and rehydration, for intense training of longer duration (2 hours or more). It is for athletic training, especially when outdoors.

Amino acids (BCAA, Arginine) with/without Amylopectin- BCAA (for increased energy levels) and Arginine (for increased muscle pump and faster recovery)- with amylopectin or for faster uptake. For intense training of any duration. It is for both intense weight training / cardiovascular training and athletic training.

Water intake before and during a competition/ exercise session should equal loss in sweat, so that there is no change in body weight. Athletes are unable to sense when they need water before, during and after an event. Because there is no evidence that drinking too much water interferes with performances, there is no reason to restrict water intake before exercise. (too much liquid during exercise causes feeling of fullness and sluggishness)

Thanks Giving

This article is written and submitted to The E Today by Shrushti Mehta.

We thank her for her research and analysis and hope to see the awareness about health and nutrition being spread ahead to larger mass of our citizens.

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