Hydration

What are the three levels in the ACSM strength of recommendation taxonomy?

A (high-quality evidence), B (inconsistent/limited evidence), and C (consensus or opinion-based evidence).

What type of evidence supports a "Level A" recommendation?

Consistent and good-quality experimental evidence regarding morbidity, mortality, exercise performance, and physiologic responses.

Name three physiological systems that hydration directly affects.

Cardiovascular (cardiac output, blood pressure), central nervous system (brain temperature and function), and thermoregulatory/metabolic systems.

How does dehydration affect performance?

It impairs oxygen delivery, disrupts temperature regulation, increases perceived exertion, and negatively influences mood and cognitive function.

What is the primary purpose of sweating during exercise?

To cool the body by releasing heat through evaporative cooling.

List three factors that can increase sweating.

High environmental temperature/humidity, intense physical activity, and lack of acclimatization.

How is sweat loss typically measured in athletes?

By weighing before and after exercise; a loss of 1 pound equals roughly 16 ounces of sweat

How does dehydration contribute to muscle cramps?

Dehydration, along with electrolyte deficits and muscle fatigue, can disrupt neuromuscular function, leading to cramps.

Which electrolytes are commonly lost during excessive sweating?

Sodium, chloride, potassium, magnesium, and calcium.

Why is electrolyte loss significant for athletes?

It can contribute to muscle cramps and impair neuromuscular function, especially when combined with dehydration.

What urine color indicates proper hydration according to ACSM guidelines?

A pale lemonade color, typically with a color rating less than 3 on the urine color chart.

What does a Urine Specific Gravity (USG) below 1.020 indicate?

It indicates that an individual is well hydrated.

How can athletes use body weight to assess hydration status?

By weighing themselves before and after exercise; weight loss is used to calculate sweat loss (1 lb lost equals about 16 oz of fluid lost).

Why do some athletes purposefully dehydrate, and what are the risks?

They dehydrate to make weight in weight-class sports, but this practice increases the risk of heat injury, performance deficits, and serious health issues.

What are three major health risks associated with dehydration?

Heat-related illnesses (heat exhaustion/heat stroke), muscle cramps, and rhabdomyolysis leading to potential kidney failure.

How does dehydration contribute to hyponatremia?

when significant fluid loss occurs alongside a loss of electrolytes, particularly sodium, leading to a dilution of the remaining sodium in the body,

What is rhabdomyolysis, and why is it dangerous?

It is the rapid breakdown of muscle tissue, which can lead to the release of muscle cell contents that may cause kidney failure, particularly when dehydration is present.

How does air travel affect hydration, and what is the recommendation?

Low cabin humidity and pressure can increase fluid loss (~500 ml/hr); it is recommended to drink about 16 ounces of water per flight hour.

What adaptations occur during heat acclimatization?

Within 5-7 days, heart rate drops, plasma volume expands, and core/skin temperature decreases.

Why are females and older adults at increased risk in hydration contexts?

Females may experience lower sweat rates and a higher risk of hyponatremia, while aging blunts thirst and alters electrolyte regulation, increasing dehydration risks.