U.S. Masters Swimming members Jennifer Thayer and Mark R Yoder delve into the detail of how proper hydration can improve athletic performance and your health.

You lose fluids during workouts primarily in the form of sweat and respiratory water vapour losses, but you can’t tell you’re sweating because you’re in the water. Your first sign of dehydration might be a muscle cramp in the middle of a set.

Improving your swimming and health requires balanced consumption of fluids and electrolytes such as sodium and potassium. It’s critical for athletes, including those over 60, to understand how certain age-associated physiological and lifestyle changes affect proper hydration and to develop—and follow—a plan to deal with those challenges.
 

Major Factors in Your Hydration Needs

Many general and age-related factors can affect how much fluid is lost before, during, and after athletic activity.

Workout parameters. Increasing the frequency, intensity, or duration of your workouts can increase how much fluid and electrolytes you need to consume.

Location. Where you’re training can also have an impact. You require more fluids and electrolytes if you train in a hot, excessively dry or humid environment or at altitude, and you need to keep in mind that training in cold conditions has been associated with a lower sensation of thirst.

Medications and diet. Both ageing-associated chronic conditions and the natural ageing process can result in reduced kidney function, which can affect fluid balance and electrolyte needs and increase recovery time. Medications and specialised medical diets commonly prescribed to older people can also affect fluid and electrolyte needs. For example, diets high in fibre may require active increases in fluid and electrolyte consumption, and certain blood pressure medications and diets lower in sodium and potassium may require adjustments to recommended fluid and electrolyte intake under different environmental and training conditions.

Assessing if you’re under-hydrated or over-hydrated, understanding what, when, and how much to drink to ensure adequate hydration, and knowing when to consult a health care professional to assist you are all key to achieving and maintaining proper hydration, which can help optimise overall health and athletic performance.
 

 

Hydration Status: You Can’t Manage it if You Don’t Measure It

Weight changes can be used to help assess hydration status.

• Day-to-day, first-thing-in-the-morning weight changes less than 1 percent of your total body mass can indicate adequate hydration.
• Pre- to post-activity weight loss should be kept to less than 2 percent of body mass to minimise performance deficits and health risks.
• Pre- to post-activity weight gain can indicate over-hydration, which can also lead to serious health risks.

A simple hydration strategy is to look at your urine by midday. A common rule of thumb is that clear urine, with little or no yellow tint, can indicate that you’re properly hydrated. This method, however, is inexact and, without additional considerations, can still leave you over- or under-hydrated.  Diet, some medications, supplements, vitamins, body compensations for training, and other factors can impart colour to your urine, which can affect a simple colour test. For example, B vitamin supplements can give urine a bright yellow or orange colour, which can make it harder to use urine colour to assess hydration.

To increase measurement accuracy, over-the-counter tests are available to measure urine specific gravity and osmolality.  General guidelines by the American College of Sports Medicine suggest that first-morning urine specific gravity less than 1.020 or urine osmolality less than 700 mOsmol/kg generally indicate adequate hydration.  It is important, however, that these tests be used properly—in careful compliance with the manufacturer’s instructions and consistent with your health care professional’s guidance. For example, changing the time of day your test is performed can significantly affect measurements. Moreover, these tests constitute a limited proxy of overall hydration, particularly as it applies to athletic performance, so there isn’t one absolute measured value that necessarily indicates optimal hydration for every person under all conditions and circumstances.

Nonetheless, in consultation with your healthcare provider, these assessment tools can be very helpful to establish personalised baselines for proper fluid and electrolyte intake and develop an individualised hydration management plan that optimises both health and athletic performance.
 

 

What to Drink and When

Fluid needs are specific to each individual. However, there are a number of general recommendations that might help. Reminder: Consult your health care provider before using any specific recommendations to adjust your fluid and electrolyte intake, especially if you have health conditions.

• Consume 5–10 ml/kg of fluids two to four hours before a workout or competition. A 150-pound person weighs 68.2 kilograms. The low end of the recommended pre-workout range for this person can be calculated by multiplying 68.2 by 5 to get 341 milliliters. To covert to fluid ounces, divide that number by 29.57 to get 11.5 ounces. The high end of that range would be 23.1 ounces.
• Consume drinks and foods containing carbohydrates and electrolytes before and during your workout to ensure adequate energy, fluid, sodium, and potassium intake, especially if your physical activity will last 60–90 minutes or longer. You can do this by drinking something with balanced electrolytes and a carbohydrate content of 6–8 percent or consuming carbohydrate-, sodium-, and potassium-containing snacks with water.
• After a workout, consume foods and beverages containing sodium and other electrolytes and carbohydrates to help you rehydrate and aid in overall recovery. You can also consider adding protein, especially proteins which contain a high amount of the amino acid leucine, to help with muscle growth.
• Maintain proper fluid and electrolyte intake throughout the day by consuming flavoured drinks in addition to water (within the parameters of a healthy diet), drinking small amounts of fluid throughout the day, salting food to taste to encourage additional fluid and electrolyte consumption (as appropriate to individual sodium requirements), and having a drink available during meals and snacks.

Adequate hydration depends on many individual factors. Knowing what’s right for you given your personal training objectives and medical history is critical to making—and following—a plan that’ll contribute to both a healthy lifestyle and optimised athletic performance. Personalisation is key to optimal hydration.
 

Article first published on 28th August 2020 by Jennifer Thayer and Mark R Yoder on U.S. Masters Swimming.

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