by Carol E. Torgan, Ph.D.
If you've paged through any biking, running or fitness magazines
recently, you may have noticed a large number of ads for new products
promising to speed recovery, minimize cell damage, rebuild muscle
protein, and even slowdown aging. They have names like BIOfixTM, Muscle
Recovery, BarTM, Damage Control, "Master Formula", and Endurox "R4".
Recovery aids represent a logical sequence in trends, following on the
heels of pre-exercise rituals such as carbohydrate loading, and
during-exercise sports aids, such as drinks, bars, and gels. To
determine if these products are beneficial, it helps to understand
the needs of the muscles following exercise. The major concerns are
replenishing fuel stores and decreasing muscle damage plus building new
One of the main sources of fuel for exercise is glycogen, which
is simply glucose residues branched together into large granules, and
then distributed throughout your muscle fibers. As you exercise, the
glucose is used for energy and each glycogen granule gets smaller. Your
liver also stores glycogen and releases it into the blood stream as
glucose so it can be taken up by working muscles. Ingesting
carbohydrates during exercise helps maintain the blood glucose levels,
and thus prolongs endurance. However, once you deplete your muscle
glycogen and can't maintain blood glucose levels to meet the demands of
your pumping, screaming muscles, you bonk or hit the wall. After
exercise, there is a window of around two hours when your muscles are
primed to suck up glucose and rebuild their glycogen stores. Thus, as
we've mentioned before in this column, it's important to eat
carbohydrates within a few hours after exercising. This increases
levels of glucose in your blood stream and causes insulin to be secreted
from the pancreas which further triggers the muscles to soak up glucose
and form glycogen. If you plan to ride hard on successive days, itís
crucial to replenish your glycogen stores after each ride.
As you exercise, your muscles generate signals that trigger them
to adapt(make more enzymes for better endurance, make more contractile
machinery to generate more power). They accomplish this by synthesizing
new proteins. Strenuous cycling may cause tissue breakdown and protein
degradation due to mechanical forces and the release of free radicals.
Thus it makes sense to eat protein after exercise to supply amino acids
to optimize tissue rebuilding. Consuming protein may also be
beneficial by further increasing insulin secretion, thus accelerating
glucose uptake and glycogen formation in muscles. Consumption of
anti-oxidants such as vitamins C and E may also be advantageous.
Armed with this knowledge, it's no surprise that recovery aids
are composed of a blend of carbohydrates and protein, with added
vitamins such as A,B6, B12, C, D, E; minerals such as calcium, sodium,
potassium, and iron; and even grapeseed extract and green tea extract.
The products vary in their ratios of carbohydrate to protein, their
levels and types of vitamins and minerals, their form (drinks, bars, or
pills), their cost and their claims.
Is there scientific evidence that they work? Yes and no. The
more reputable companies will fund researchers to test their products in
carefully controlled trials, and then the results may be published in
peer-reviewed scientific journals. Ideally the studies are double
blind, cross-over designs comparing a specific product to either a
placebo or another product. Itís double blind because neither the
subjects (e.g. cyclists) nor researchers doing the analyses know the
identity of the products (they may be labeled drink A and drink B) which
eliminates any biases. In the cross-over part, the subjects try drink A
or B one week, and then come back a week or two later, and get tested
with the other product. The results between the two trials are then
statistically analyzed for a number of variables such as glucose,
insulin and lactate levels, and even muscle glycogen content.
Unfortunately, an exhaustive search of the scientific literature reveals
that only a few studies have been published on these products, despite
the ads touting university research demonstrating their effectiveness.
Some research has shown that specific products can enhance recovery,
while other research has shown that the same product does not work
better than a placebo. The studies tend to have different formats (type
and length of exercise, timing of ingestion) and make different
measurements, so they can be difficult to compare. The bottom line is
that more scientific research is needed before any definitive
conclusions can be reached.
Should you fork over money for one of these products? If you
typically have no appetite after biking, or just have a beer or soda,
recovery products offer an alternative to help you refuel, since they
are basically a packaged mini-meal with extra vitamins and minerals.
The caveat is that many of them contain a large number of calories and
can lead to weight gain if used often or combined with meals. If you
eat regularly after exercise and maintain a well balanced diet, then you
may find them to be an unnecessary expense.Some athletes swear by these
products according to the web sites, which are full of testimonials.
However, some dietitians suggest that basic carbohydrate and protein
meals such as rice and beans or fruit and cottage cheese will fit the
bill just as well. The key is to try a couple of alternatives and find
the one that works best for you. I have a friend that favors waffles
with peanut butter, and one that swears by good old fashioned cereal and
milk topped with a banana. Do you have a favorite pre or post ride
meal? Send us an e-mail at [PPTCmeal at yahoo.com] and we'll publish
the tastiest (and most disgusting) in a future column.