Fluid Foundations: Hydration and Healthy Aging
Why Is Hydration Important For Longevity?
Hydration is important at every age but it’s especially critical as we age. As we age, our ability to stay properly hydrated declines. Older individuals are more vulnerable to dehydration because aging compromises both the intake and output regulatory processes required for maintaining adequate healthy hydration. We advise all our Longevity patients to pay attention to their hydration and help them build healthy hydration habits into their daily routines.
Demystifying Hydration: How It Works
Water has been called the elixir of life due to its absolute necessity for survival. Staying optimally hydrated is a dynamic dance between water intake and water loss, and under normal circumstances, our internal regulatory processes do an efficient job of maintaining this equilibrium. Our thirst mechanism alerts us when we need to drink more water, while our kidneys, sweat glands, and even our breathing help regulate water and electrolyte loss through urine, sweat, and even our breath in the form of water vapor. However, there are situations when our regulatory processes don’t keep up, and we are more at risk of dehydration. This can happen when we lose a lot of fluid quickly, during prolonged exertion, or longer periods in hot and dry environments, or from intake of diuretics like alcohol and coffee without adequate water intake. We get almost 80% of our water through food, so excessive caloric restriction can also result in dehydration even though we may be drinking the same fluid volumes as before.
The Cost of Dehydration: Effects on the Body
Adequate hydration is essential for optimal health. Hydration status can have widespread effects on functioning, affecting a variety of things like neurological function, kidney function, gastrointestinal function, and even metabolic health. Neurologically, dehydration can affect cognitive performance. Studies of dehydrated adults show that a dehydrated brain shows signs of increased neuronal activation during a task, indicating that the brain has to work harder to complete a task when dehydrated. This additional effort could result in more fatigue, a change in mood, or a decline in cognitive performance.
From a physical standpoint, the body performs better when hydrated. If you’re an athlete looking to optimize performance, staying hydrated is especially important. If a dehydrated athlete performs their usual workout, they’ll notice a higher heart rate as compared to their normal for that exercise, indicating that their heart has to work even harder to get the same results. Other things an athlete can experience due to dehydration would be a higher core body temperature, feeling like they have to work a lot harder for the same results compared to if they were hydrated, taking longer to finish a workout, and/or a reduction in overall power. Besides enhancing performance, staying well-hydrated can also reduce post-exercise fatigue.
For the digestive tract, even mild dehydration can affect digestive system functioning, causing constipation. The kidneys manage water balance and waste removal and kidney ability can be hindered from dehydration. Low water intake is associated with a higher likelihood of high blood sugar, and studies show that dehydration can even have a correlation with the risk of metabolic disease. While acute dehydration can manifest with symptoms like dizziness, fatigue, and a drop in blood pressure, chronic dehydration can be more insidious, raising the risk of kidney damage, substantially hindering body functioning, exacerbating hypertension, and causing other long-term complications. All of this is to say that keeping ourselves properly hydrated is essential to feeling and performing our best!
The Link Between Hydration and Aging
As we age, our ability to stay properly hydrated declines. Older individuals are more vulnerable to dehydration because aging compromises both the intake and output regulatory processes required for maintaining hydration. From an intake standpoint, the thirst response can become blunted with aging, so an older individual may not recognize feeling thirsty even when significantly dehydrated. From an output standpoint, the kidneys are crucial for managing water balance and waste removal and since kidney function declines with aging, they become less efficient at managing this water balance. When functioning optimally, the kidneys alter the amount of water and salt excreted in urine based on hydration status. If dehydrated, the kidneys will hold onto more water to keep you better hydrated and make your urine more concentrated. If sufficiently hydrated, the kidneys will signal that it is safe to excrete more water, making your urine less concentrated. Between the ages of 40 and 59, the body’s ability to reduce excretion based on total body water is diminished. By the ages of 60 and 79, this ability is almost fully absent, so the kidneys won’t hold onto water as effectively, contributing to the risk of dehydration. On a separate note, in previous blogs, we’ve touched on muscle mass declining with age. As we age, generally lean mass decreases and fat mass increases. Because muscles hold more water than fat cells do, as our lean mass decreases, we also experience a reduction of total body water which contributes to hydration issues.
Proactive Hydration: Strategies for Aging Gracefully
Hydration is not one-size-fits-all, as hydration needs vary based on several factors like an individual’s activity level, environment, and certain health conditions and medications. While the National Academies of Medicine provides general guidelines – about 6-9 cups of fluids daily for women and 8-12 cups for men – unique needs vary. Here are a few tips to be proactive about hydration:
- Assess your hydration status with the help of your doctor: Assessing hydration status on your own can be difficult, as clinical signs like heart rate, skin elasticity, mouth dryness, and perceived thirst aren’t very reliable indicators. Even urine color can be influenced by things outside of hydration status, like taking certain supplements for example. More modern methods, such as blood tests through a doctor measuring serum osmolality, offer a more accurate gauge to diagnose low-intake dehydration.
- Be intentional with water intake: Because our natural thirst mechanism becomes less reliable as we age, it’s important to be intentional about drinking enough water. Starting your day with a large glass of warm lemon water, before reaching for coffee, is a great habit to get into to start the day hydrating and kickstarting digestion. You can also invest in a large reusable water bottle and take it with you to remember to drink throughout the day. Out of sight, out of mind, but if you have a large water bottle on your desk you may be more likely to drink! Many companies even make large water bottles with clearly marked measurements on the outside now, which can be a practical way to keep you on track if you’re committed to meeting daily intake goals.
- Take your exercise routine into account: Exercise amplifies fluid requirements. The environment you exercise in (think temperature and humidity), the intensity of the activity, and the amount you sweat play pivotal roles in determining how much additional water you should drink. A practical guide to follow by Andrew D. Huberman, a neuroscientist and host of the Huberman Lab Podcast, is to take your body weight (in pounds) and divide it by 30. This calculation gives the additional ounces of fluid to consume every 15-20 minutes or so during your workout (does not have to be exact). For example, for a 150-pound person, this would mean drinking an additional 5 oz every 15-20 minutes during exercise.
- Continue building/maintaining muscle mass: The emphasis on maintaining and building muscle mass as we age cannot be overstated! A body with more lean muscle mass acts as a reservoir for body water, reducing potential impacts of dehydration. To continue building and maintaining muscle, it’s important your diet has enough protein (generally around 1.2-1.6 grams per kg body weight, but individual needs vary) and you’re engaging in regular resistance training. Booking a Fitness for Longevity Consultation with us can help pinpoint your unique needs!
- Consider supplementing with electrolytes and glucose when appropriate: Plain water, though essential, isn’t always enough to keep us hydrated, especially after intense physical activity or lots of fluid loss. Here, focusing on adding electrolytes first, especially sodium, magnesium, and potassium, can help our cells function optimally. Some activities that often warrant electrolyte supplementation include a hot sauna session, hot yoga, exercising in hot and humid temperatures, or any type of exercise where you lose a substantial amount of sweat. Generally, glucose should only be needed in addition to the electrolytes in situations with longer periods of extreme exercise, for example, while running a half marathon. In these situations where our glycogen levels deplete, glucose not only acts as a substrate for ATP (fueling energy) but also facilitates water absorption, helping us absorb more water through a co-transport mechanism with sodium. For activities that last up to 2 hours, adding glucose generally isn’t necessary due to sufficient muscle and liver glycogen reserves in the body.
Resources:
Hydration Boosters: Recommended Supplements
Electrolyte Supplements: to replenish electrolytes without affecting blood glucose levels.
- E-Lyte by Body Bio: Liquid form, mimics electrolyte levels in the body for optimal hydration without added flavor. Take 2-3 capfuls of concentrate to 8 oz. of water. *can be purchased through FullScript if you have an account with us.
- LMNT Electrolyte Powder Packets: Flavored electrolyte drink mix packets in powder form that you can add to water.
- Nuun Sport Electrolyte Tablets: Flavored electrolyte tablets (to drop and dissolve into water).
Electrolytes Plus Glucose Supplements
- Liquid I.V. Hydration Multiplier: For all-in-one electrolytes plus glucose, optimizes water absorption by pairing glucose with sodium. Mix packets in powder form that you can add to water.
Podcasts:
Huberman Lab: How to Optimize Your Water Quality & Intake for Health. Available on Apple Podcasts, Spotify, and through the Huberman Lab website.
Peter Attia: #200 – AMA #33: Hydration—electrolytes, supplements, sports drinks, performance effects, and more. Available on Apple Podcasts, Spotify, and through Peter Attia’s website.
References:
Li, S., Xiao, X., & Zhang, X. (2023). Hydration Status in Older Adults: Current Knowledge and Future Challenges. Nutrients, 15(11), 2609.
Betsy Mills. (2020). Can Dehydration Impair Cognitive Function? Cognitive Vitality
Photo by Ketut Subiyanto
