In your April 25th column (More prepping for long rides), you mention weighing before and after a ride. Is the weight differential entirely fluid or food in the stomach? Can you say a bit more about this differential? Should riders shoot for some change, no change, under what circumstances?
The difference between your weight before and after a training ride represents the amount of sweat that you did not replace with fluid intake during the ride. Even losing 2-percent of your body weight, about 3.5 pounds for a 165-lb. cyclist, can decrease your endurance, particularly in warmer weather conditions. The goal is to minimize your overall fluid deficit without over drinking during the ride. While over drinking is possible in a cyclist with a very low sweat rate, most of us finish harder rides in some state of dehydration. Some cyclists will also have such a high sweat rate that matching their sweat losses simply isn’t possible due to gastrointestinal intolerance to larger amounts of fluid. It is important that you check your sweat rate to determine your own individual sweat losses in various weather conditions and as you become acclimated. It is best if you test your sweat rate on a shorter ride, perhaps one hour when consuming only a carbohydrate-electrolyte beverage and no solid items such as gels and bars. Below is an example of how to check your sweat rate. Sweat rates can range greatly in cyclists, anywhere from 0.5 to 3 liters per hour.
1. Check your weight before and after training and calculate your weight loss.
Weight before training: ________________
Weight after training: __________________
Amount of weight lost: _________________
2. Know the amount of fluid consumed during the training session.
Ounces (ml) of sports drink consumed: __________________
(squeeze bottles are 20 to 24 ounces/ 600 to 720 ml)
Ounces (ml) plain water (if any) consumed: _____________________
3. Convert the amount of ounces (ml) of fluid consumed to weight.
• 30 ounces of fluid weighs 2 lb.
• 1000 ml fluid equals 1 kg.
4. Add the amount of weight loss and the weight of the fluid consumed.
________________________________________ = __________ lb. (kg)lost
Convert this total lb. (kg) weight loss to ounces (ml).
5. Divide the total ounces (ml) of weight loss by the number of hours of training, to determine the amount of ounces lost in sweat per hour.
____________________ Sweat losses per hour
|Weight before training: 165 lb. (75 kg)
Weight after training: 162 lb. (74 kg)
Total weight loss: 3 lb. (1.4 kg)Fluid Consumed: 60 ounces (1800 ml) fluid during a three hour bike ride.
60 ounces (1800 ml) fluid weight 4 lb. (1.8 kg)
Total weight loss and weight of fluid. 3 lb. (1.4 kg) + 4 lb. (1.8 kg) = 7 lb. (3.2 kg)
The seven-pound total weight is equivalent to 105 ounces (3.2 kg equals 3200 ml fluid) divided by three hours of training.
Amount lost in sweat per hour: 35 ounces (1060 ml) per hour for sweat losses
I use electrolyte tablets pretty liberally to prevent cramping. In your column on muscle cramps you seem to suggest that their use should be a last resort, and then only in a limited dose. What’s the downside of taking electrolyte tablets?
Electrolyte tablets can definitely be used during training and racing if you struggle with muscle cramping that responds to electrolyte supplementation. However, I would suggest that you definitely use a higher sodium sports drink when training and racing and try working with that first as an effective and convenient method of higher electrolyte replacement during training. Because adequate fluid intake is also closely tied to preventing muscle cramping, drinking adequate amounts of a higher sodium sports drink can also go a long way to curb the cramping. These sports drinks often provide higher amounts of potassium, calcium, and magnesium as well. Once you have reached a plateau in how much fluid you can comfortably consume to minimize the sweat loss deficit, you can determine what your sodium intake may be per hour. It is possible that you can consume anywhere from 600 to 1200 milligrams per hour. Unlike your fluid losses, it is really not possible to determine what your sodium losses are per hour other than in the laboratory setting. Of course salt marking on your training clothing can indicate that you are a salty sweater. So if these higher sodium sports drinks are not adequate to replace your sodium losses, you can add electrolytetablets/supplements to the mix.
Many tablets/supplements contain not only sodium but the other electrolytes as well. Since the amount that you should consume to replace electrolyte losses is still not clear, you can add in electrolyte tablets/ supplements as needed to prevent a decline in performance, low levels of blood sodium, or in your case, muscle cramping. The amount of sodium in one tablet of products can vary widely, ranging from 100 mg to 500 mg. Sweat sodium losses can range greatly from 400 to over 1000 milligrams per liter of sweat.You can determine your sweat rate and then try to replace sodium at a reasonable level between the high sodium sports drink and salt/electrolyte tablet. Generally for a very salty sweater, consumption of over 1000 mg per hour can be met with a carbohydrate electrolyte beverage and a salt tablet.
Are there any dangers to over-supplementing? Yes, possibly. If you over consume sodium and don’t take these products with adequate fluid, you could possibly risk some gastric irritation and upset. Sodium tablets should always be consumed with fluid, and “buffered” products are also available.Over-supplementing also provides no performance benefits. But you do need to consume enough sodium during exercise to prevent an excess of sodium loss through sweating which can lead to low blood sodium levels and in some susceptible cyclists, muscle cramping.
A fishy question
I have a simple question, which may not have a simple answer. Are there nutritional advantages to eating wild salmon as opposed to farmed salmon? Also, most tuna is wild, should always be consumed over “farmed” salmon?
As you are aware, seafood is good for you and one of the best sources of the healthy omega-3 fatty acids DHA (docohexaenoic acid) and EPA (eicosapentaenoic acid). Both of these fats play important roles in your immune and neurological systems and are linked to a lower risk of heart disease. But because of the concern around contaminated waters, consuming fish is not entirely risk free. One recent report from Harvard’s School of Public Health concluded that the health benefits of eating fish exceeds the risk of contamination, and that one to two fish meals weekly can reduce risk of death from heart disease by 36 percent. Another report from the Institute of Medicine (IOM) did advise that individuals at risk for heart disease could reduce their risk by consuming fish regularly. They also advised that a variety of fish be consumed to reduce risk of contaminants from one source.Unfortunately, fish can be contaminated with mercury and PCBs. PCB’s accumulate in fatty fish, just as mercury does, though these fish are good sources of EPA and DHA. Fish most likely to be contaminated are large predatory fish, especially shark, swordfish, tilefish, and king mackerel. Both farmed and wild salmon are good sources of DHA and EPA and are low in mercury, but can be contaminated with PCBs. Farmed salmon is more likely to contain high levels of PCBs than wild salmon, with two exceptions. Farmed salmon from Chile and Washington state are relatively low in contaminants. The lowest in contaminants is wild Alaskan salmon. In regards to tuna, make chunk light your regular tuna. Limit the higher mercury choice of canned white albacore to no more than one serving per week (3 ounces). Fresh tuna, a very fatty fish, is also high in mercury. Other safer seafood choices include: crab, clams (farmed), halibut (Alaska), herring (Atlantic), mackerel (Atlantic), sardine, scallops (farmed), shrimp (farmed), and tilapia (farmed).