New Fluid Replacement Recommendations from ACSM

The American College of Sports Medicine (ACSM) recently updated their position on how to best hydrate before, during and after excercise. Is re hydration up to speed? Read on to find out what the experts are saying.

Is hydration important to performance?
Absolutely! Exercise generates internal heat. To function at your best athletically, that heat needs to be released. As your internal temperature rises, your body responds by increasing blood flow to your skin and initiating sweating. More blood flowing to your skin transfers heat away from your core and toward the exterior of your body where it can be released. The evaporation of sweat in warm or hot weather is the primary avenue for losing heat and so sweat losses can be substantial. Sweat is composed of water and electrolytes and if they aren't appropriately replaced, dehydration can result. Conversely, if too much fluid is consumed, overhydration or hyponatremia can occur. Both dehydration and overhydration impair physical performance and can pose serious health risks. So, having a hydration plan is critical to athletic performance and important for your health.

Don't zone out
On average, athletes typically lose anywhere from 500 to 2,000 ml (17 to 67 fl oz) of sweat per hour. That equates to roughly 1 to 4 pounds worth of sweat. You give yourself the chance to perform at your best if you don't lose anymore than 2% of your body weight due to fluid loss during exercise.

So, if you weigh in at 150 pounds before exercise, you need to remain somewhere between 150 and 147 pounds during exercise to perform at your best. This 2% rule is called your hydration zone. Know it and stick to it. It's a strategy that will pay dividends.

What happens when you exceed the 2% weight loss hydration zone is that the very same exercise you did yesterday with relative ease is going to feel more difficult to do. You're going to have to strain to keep up the pace. Falling out of your hydration zone also affects your ability to think clearly and tactically, especially in hot-weather conditions. Give yourself every chance to be your best by hydrating sufficiently to stay in your hydration zone.

Know your sweat rate
A key message from the new recommendations is that sweat rates vary tremendously from one athlete to the next, and from one activity to the next. Athletes in the National Football League and cross-country runners can work in the same scorching heat and for the same length of time, yet football players typically lose over twice the amount of sweat as runners. Why the difference? Because fluid losses are determined by a variety of factors including body weight, type of clothing and equipment worn, and how acclimated athletes are to heat.

Sweat rates vary and you need to know your own because state-of-the-art hydration today means every athlete has an individualized hydration plan. In other words, the right hydration plan is based on your personal sweat rate, not the sweat rate of your training partner. One-size-fits-all fluid intake recommendations no longer fit; especially if top performance is your goal. To measure your sweat rate, use PowerBar's online Hydration Calculator. You'€™ll be guided through a simple one-hour test workout that will calculate your sweat rate. Conduct the test workout at an exercise intensity and in climate conditions similar to the conditions you encounter during training and competition. Better yet, test yourself at different exercise intensities and in different climate conditions, and as your fitness level changes. By repeating sweat rate testing under varying conditions, you will better understand how your body responds to different conditions. This will help you fine-tune your hydration plans for whatever you encounter during training and competing.

Putting your sweat rate to good use
Knowing your sweat rate is half the battle. The other half is actually consuming the fluids you need and knowing what type of fluids to consume.

Lots of athletes find it difficult and uncomfortable to consume fluids at a volume that matches their sweat rate. If you are in that camp, don't despair. Remember that your hydration zone is losing no more than 2% of your pre-exercise body weight due to fluid loss during exercise. So, you don't need to exactly match your sweat rate. You just need to make sure that you don't drop out of your zone while you are exercising.

Putting this into practice:
Let's say you weigh 150 pounds, you lose about 2 pounds of fluid per hour during exercise according to your sweat rate test (~31 fl oz per hour), and you plan to compete in an event that will probably take you 3 hours to finish.

If you do the math, your hydration zone weight is between 150 and 147 pounds. Given your sweat rate, after the first 90 minutes of exercise you would be at the low end of your hydration zone, and you would drop out of your zone thereafter. However, by consuming fluid at just half your sweat rate (~16 fl oz per hour instead of 31 fl oz per hour) throughout the event, you could remain within your hydration zone for the full 3 hours of exercise.

The point is to know your sweat rate and hydrate strategically so that you remain comfortable and within your hydration zone. You may also be able to gradually train yourself to absorb more fluid during exercise. So, if you're having trouble consuming enough fluids, start at a volume you are comfortable with, and gradually increase the volume consumed per hour during training until you reach a more acceptable level of intake.

Sport drink versus water and the lowdown on electrolytes
Water only contains fluid. A well-designed sport drink contains fluids, carbs, and electrolytes. Which drink is best for you depends on what you are doing and for how long.

For low-to-moderate intensity activities in mild conditions that are less than an hour in length, water is generally fine for rehydrating.

For endurance events of one hour length or longer, and for events in hot-weather, a sport drink is generally a better choice. The carbs in a sport drink can help sustain or extend your ability to perform athletically. The key electrolytes in a sport drink are sodium and chloride which together form salt. Of the electrolytes in sweat, these two are lost in the greatest amounts during sweating. Including these electrolytes in a sport drink helps you replace those lost from sweating, retain consumed fluid, and stimulate thirst. In addition, flavored sport drinks help increase the amount of fluid ingested compared to plain water.

Carbs and electrolytes can also be consumed in non-fluid sources like gels, energy bars, and other foods, just as long as they are paired with sufficient water to meet your fluid needs.

Finally, when it comes to caffeine, the ACSM recommendations indicate that the evidence available suggests caffeine consumption may help sustain exercise performance and it probably doesn't alter hydration status during exercise.

How can you tell if you're rehydrated?
Let's say that yesterday's workout was a long one, and in very hot conditions. You followed your usual rehydration and refueling strategy, but want to make sure that you're fully rehydrated before engaging in another workout. What can you do?

According to the new guidelines, a practical method for assessing your hydration status or balance includes a combination of measuring body weight and evaluating urine color. The catch is that each method needs to be done properly.

Measure your body weight upon arising in the morning, after urinating, and compare this to your typical body weight. Your typical body weight should be the average of repeated body weight measurements taken in the morning. Changes in eating and bowel habits, and timing within the menstrual cycle can influence body weight, so multiple measurements are needed to establish a valid baseline value.

In addition to measuring body weight, urine color can be evaluated in the first morning urine sample or in a urine sample taken after several hours of stable hydration status. Downing large quantities of fluids after exercise can lead to the production of dilute urine long before you are actually fully rehydrated, so don't be fooled by a urine sample taken soon after chugging a water bottle full of water or a sport drink. Testing your urine color several hours after actively rehydrating is advised. Urine that is dark in color (highly concentrated), is a sign that you've not yet fully rehydrated. The goal is a urine color that is light yellow in color, something close to the color of lemonade.

Hydrate before exercise
Before exercise, and when the timing is feasible, ACSM recommends that you consume fluids at least 4 hours before exercise. If you are well hydrated this should lead to urine production. If it doesn't, or the urine that is produced is dark in color, you should drink more fluid about 2 hours before exercise. This will allow sufficient time for urine to be eliminated before starting exercise. According to ACSM, the amount of fluid to consume before exercise depends on your body weight:

Consuming a sport drink with sodium, small amounts of salted snacks, or sodium-containing foods at meals will help stimulate thirst and retain the consumed fluids. Also, fluids that are cold in temperature, contain some sodium and carbs, and are flavored can enhance the appeal of beverages and help promote fluid consumption.

Rehydration after exercise
After exercise, the goal is to make up any fluid deficit resulting from exercise and to replace electrolytes lost from sweating. How fast to rehydrate depends on when your next training session or competition takes place. If you just ran your first marathon and don't plan to step foot into those running shoes for at least a few days, then normal meals, snacks, and beverages will generally rehydrate you within about 24 hours.

If you've lost excessive fluid (more than 2% of your pre-exercise body weight) and need to be fully recovered in less than 12 hours in order to be ready for another workout or competition, a more aggressive rehydration program is needed. The new ACSM recommendations suggest that you drink about 23 fl oz of fluid for every pound of weight lost during exercise. Drink the necessary fluid gradually between the time you finish your first workout and 1-2 hours before you start your next one.

Also, consuming sodium while rehydrating during recovery will help you retain ingested fluids and help stimulate your thirst. You can get sodium from your recovery beverage, sport drink, energy bar or gel, salty snacks, and meals.

PowerBar tools and products
The PowerBar website provides easy-to-use tools and state-of-the-art products to meet the individual hydration and fueling needs of athletes:

• Hydration Calculator: Calculate your sweat rate
• Recovery Calculator: Get specific hydration and sports nutrition recommendations to promote recovery after a workout or event

References

1. American College of Sports Medicine; Sawka MN, et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc 2007;39:377-390.

Nutritional Supplements: Part 2, Protein

from the Cadence Cycling Blog, June 16, 2007

One of the most common misconceptions endurance athletes have is that they need mass quantities of protein in their diet. The image that comes to mind for me is Rocky cracking a dozen raw eggs in the blender before heading out on his run. In reality, getting enough carbohydrates, and more specifically, good carbohydrates is much more of a challenge for most of us cyclists and triathletes.

Protein is required for muscle growth, repair and maintenance as well as the formation of hormones, enzymes, neurotransmitters and other components of the immune system. it is also required to produce hemoglobin in the blood. Most endurance athletes should aim for 15-20 percent of their Caloric intake from protein. In the U.S., most of us get far more, especially if we eat out a lot. Protein is found in high concentration in meats, fish, tofu and many beans and in lower concentrations in dairy products and nuts. While it is certainly possible to consume enough protein though plant based protein sources, animal based proteins are also good sources or iron and zinc, so vegetarian athletes should look for alternate sources of these minerals.

Since we burn protein as a fuel source in longer and more intense training sessions, some protein may be useful in the recovery process. However, it is not certain whether protein is really necessary in your post workout recovery drinks. The most important thing is to aim for 0.5-0.7 grams of carbohydrate (CHO) within 30 minutes of completion of the workout. This comes out to 65-90 grams for a 130 lb woman or 80-112 grams for a 160 lb man. Whether or not it the protein is necessary, it will not hurt if protein comprises up to 25% of the Calories in your recovery drink. Most marketed recovery drinks such as Hammer Perpetuem and Endurox have a 3-4:1 CHO:Protein ratio. These mixes are great if you are at away from home at a race, a Cadence class, or anywhere where you don't have access to your blender. My recommendation, though, is to eat real food whenever possible. So if you are at home or if you are close to a smoothie stand, have that instead. Not to mention, it tastes a lot better.

If you are concerned about having enough protein in your recovery drink, be aware of the different types of protein contained in the supplements. Both Endurox and Perpetuem contain whey protein, which is derived from milk. If you are lactose intolerant or you don't digest dairy products well after exercise, you may want to try a soy, egg or rice protein powder instead. Some people may find that casein protein absorbs well, though casein is also derived from milk.

-Colin Sandberg, Cadence Cycling & Multisport

Nutritional Supplements: Part 1

from the Cadence Cycling Blog, May 27, 2007

Most dieticians will tell you that you should try to get all of your nutrients from "real food" sources rather than relying on supplements. While I would advise athletes to work on their regular diet first before thinking too much about supplements, it is virtually impossible for most of us not to have some gaps in their nutrition without taking supplements. On top of that, simply getting "enough" of a given nutrient is not the same thing as getting the ideal amount for you. Some nutritional challenges that athletes face:

- Because endurance athletes are training and competing for extended periods of time, it is necessary to eat and drink while exercising. The most commonly used supplements for endurance athletes: bars, gels and energy drinks. Since taking a tuna sandwich on a ride with us just isn't practical (and even if it was, we probably wouldn't tolerate it too well), a bar that is easy to bring along, easy to eat, digests easily and has everything we need at the time to top off the stores can be ideal. Gels come in handy when we are exercising at higher intensities and can't tolerate solid food. Energy drinks keep us hydrated, help limit salt and electrolyte losses through sweat and help us to get enough Calories.

- We breath a lot of air. Just the simple act of breathing means that we take a lot of pollution, pollen and free-radicals into our bodies. These things can make it difficult to breath, make us sick, cause cellular damage and even cancer. Even the oxygen that we rely on so much is in itself toxic to our cells. Have you ever noticed that some endurance athletes that have been doing this for a long time look a lot older than they really are? Chances are it's the cellular damage caused by all the oxygen, free radicals and sunlight. One of the biggest things you will see in vitamin supplements marketed for endurance athletes is high doses of antioxidants. These antioxidants will help to reduce cellular damage, keep you healthy and young-looking.

- Vegetarian and especially vegan athletes face the special challenge of making sure they get enough protein, and in particular, enough iron from their food. Endurance athletes rely heavily on the oxygen carrying capacity of the blood, which will be severely diminished if iron stores are low. Though plant based sources of protein and iron are plentiful, absorption rates are often lower than in meat based sources. Protein supplements can come in handy after workouts as recovery drinks, and iron supplements are necessary for many athletes, even many non-vegetarians. Like many supplements though, be careful not to overdo it, as too much iron can be toxic.

In short, athletes are not normal people. We routinely push our bodies far and above what can be considered "normal" and perhaps even healthy. But we do it because there is something special about taking ourselves to the absolute limit. To do that, we need a little help. For all the work we put into training and the sacrifices me make to compete, we want to do everything in our power to make sure that we can reach our maximum potential. There are lots of supplements out there that may be able to help us in lots of ways, but we need to be educated about them. I like to break it down to 3 simple questions...

1. Is it safe? The FDA does not regulate supplements, so it is important that we do out homework here. The last thing we want to do is actually hurt our performance, or worse yet, cause long term health problems because of a supplement. It is important that to read unbiased literature (not simply the manufacturer's studies), ask other athletes that have used the supplement about their experience, and try things in training before you try it in competition. Dosage is extremely important as well. Too little and there may be no effect and too much can be dangerous. Find out any potential side effects as well, and if you are considering taking something, make sure that the side effects don't outweigh the benefits. And make sure that you get your supplements from a reliable manufacturer, where you should have a minimal chance that you are taking something you don't think that you are taking.

2. Is it effective? There's no use using something that doesn't work, especially considering the high cost of so many nutritional supplements. Find out what the benefits really are. Will it help your recovery? Prevent cramping? Increase energy? Decrease perceived exertion? Increase threshold power? Increase sprint power? Help to build muscle mass? Help you lose weight? Make sure that whatever the supplement does, it is something that is important to you and will help you, not hurt you in reaching your goals. Again, dosage is very important. Find out how much you should take, when you should take it, what you should take it with and how often you should take it. Pay attention to the details.

3. Is it legal? Plain and simple, if it isn't legal, don't take it. You could make a pretty convincing argument that EPO can be safe if administered correctly and in the right doses. You could also argue that training too much is dangerous too your health, or to use the Dr. Ferrari argument, "Too much orange juice can kill you too". But guess what? EPO is illegal and it's cheating. If they made orange juice illegal, you wouldn't drink orange juice. My advice is to not waste your time arguing ethics. Just understand the rules and don't break them. My experience has been that the vast majority of athletes are well intentioned and do not want to cheat, but they dont always know what the rules are. It is your job as a competitor to familiarize yourself with the rules of the governing body that you compete under. Remember, USA Cycling is different from USA Triathlon is different from the UCI is different from the World Triathlon Corporation. If you don't know, ask your coach. That's what we're here for (amongst other things :))

-Colin Sandberg, Cadence Cycling & Multisport

Nutrition Tips 01

Nutrition for the Long Haul
By Chris Carmichael

Editor’s Note: If you’re interested in the CTS-Asheville Mt. Mitchell Camp, and the long, challenging Assault on Mt. Mitchell event, we thought you’d appreciate this sports nutrition column from Chris Carmichael.

At a recent cycling camp, I was talking with Dave, a rider who was clearly frustrated with his performance during long rides. Rides lasting under two hours were fine, but once he passed three hours he started having trouble with eating and drinking. As he rattled off a long list of foods, drinks, and combinations he’d tried, I realized he was actually eating and drinking too much on the bike!

The American College of Sports Medicine and most sports nutritionists recommend 30-60 grams of carbohydrate per hour of exercise, but few athletes understand where the recommendation came from. The average person can only process (or oxidize) about 1 gram of carbohydrate per minute, no matter how much is consumed. And it’s not your blood or muscles that are the bottleneck, but your intestines. There’s a limit to how fast you can move carbohydrate from the intestine to your blood, and dumping more into the gut just increases your chances for an upset stomach.

It’s easier than you think to overload your gut with too much carbohydrate. Take the example of my new friend, Dave. He was consuming half an energy bar (23g of carbs), one gel (27g of carbs), one bottle of sports drink (about 50 grams of carbs), and one bottle of water per hour during his long rides. That adds up to about 100 grams of carbohydrate per hour! Early in his rides, he was doing great because he was getting so much fluid, energy, and sodium into his body; but after a few hours the excess carbohydrate sitting in his gut was making him nauseous, bloated, and ill.

One of the easiest ways to optimize your carbohydrate intake during rides is to drink plain water while you’re eating carbohydrate-rich foods like energy bars and gels, and drink a sports drink by itself. Simply separating these two categories of foods (sports drinks and energy foods) typically brings people back into the range of 45-50 grams of carbohydrate per hour while also ensuring they’re getting adequate sodium and fluids. Two PowerBar Gels and one bottle of water provide the same amount of energy and electrolytes as a bottle of PowerBar Endurance drink.

But what if there was a way to increase the amount of carbohydrate you could digest and use in an hour? Then you could deliver more energy to working muscles, slow the natural depletion of your body’s stored glycogen, and go faster for longer! Well, new research from Asker Jeukendrup and his colleagues indicates that mixing up your sugar sources can boost carbohydrate oxidation from 1 gram/min to 1.2-1.4 g/min.

And when it comes to putting all this new information into practice on your next long ride, use the table below to figure out what to pack into your jersey pockets:


30 minutes before ride: (1) bottle of water or sports drink

Ride Length: 60 min or shorter

• Primary Concern: Fluid replenishment
• Fluids: Plain water
• Food: Nothing, or one sports gel – 27 grams of carbs and 200mg sodium
• Tip: Eat a full meal within an hour after these intense workouts for optimal recovery

Ride Length: 1-3 hours

• Primary Concern: Carbohydrate replenishment.
• Fluids: 1 bottle water & 1 bottle sports drink per hour, at least.
• Food: 30-60 g of carb per hour from bars, gels, and sports drinks – up to 80 g if you’re consuming glucose and fructose.
• Tip: Don’t dilute the sports drinks – they’re absorbed best at their correct concentrations.

Ride Length: 3-plus hours

• Primary Concern: Carbohydrate replenishment .
• Fluids: 1 bottle water & 1 bottle sports drink per hour, at least.
• Food: 30-60 g of carb per hour – more solids at the beginning and gels in the last third or the ride.
• Tip: Build your nutrition strategy around bars and gels, then supplement with additional foods (granola bars, fig bars, fruit, etc.) for variety.