A group of scientists from Pennsylvania State University recently tested seven weight- trained college students to observe the effects of dehydration on hormonal response to exercise. The researchers were especially interested in the response of two hormones, testosterone and
cortisol. Testosterone is an anabolic hormone in muscle; cortisol is catabolic.
The subjects trained under two conditions: fully hydrated and then dehydrated. Prior to the dehydrated workout they restricted food and water intake enough to cause a 3 percent reduction in body mass. The exercise routine consisted of three sets of 10 repetitions in each of eight
exercises, with a one minute rest between sets. The results showed no differences in total work output between a hydrated and dehydrated state, although shoulder strength decreased significantly when the subjects were dehydrated. The squatting strength of the subjects wasn't
Both the dehydrated and hydrated groups showed no differences in total testosterone concentration or in the release of luteinizing hormone-a pituitary gland hormone that controls testosterone synthesis in the body- after exercise. The dehydrated group did show higher cortisol
levels, though, which led the researchers to conclude that dehydration before exercise results in an increased adrenal stress response. The researchers noted that the greater cortisol response triggered by more severe dehydration may potentially repress testosterone production at
the Leydig cells. The Leydig cells are the portion of testes in which testosterone is synthesized. The researcher also found that dehydration apparently has a more potent weakening affect on smaller muscle groups.
Feel Weak? Try a Cup of Java
Exercise scientists from Appalachian State University in North Carolina recently confirmed something long known by bodybuilders: Coffee makes you stronger. The study, released at the 1995 National Strength and Conditioning Association Conference, examined the effects of caffeine
on maximum hip and leg strength. The subjects consisted of 10 men, all of whom could squat one rep with at least 130 percent of their bodyweight. They were tested twice during a week, using a one-rep- maximum squat to determine strength gains after ingesting eight milligrams of
caffeine per kilogram (2.2 pounds) of bodyweight. Thus, a 200-pound man took 720 milligrams of caffeine, which is equal to the amount in about seven cups of coffee.
The lifters didn't actually drink coffee, however. Instead, they took either caffeine mixed in artificially sweetened lemonade or a similar- tasting placebo, which they drank one hour before lifting. Surprisingly, the men's heart rates and blood pressure didn't show appreciable
differences between the placebo and caffeine groups. You'd expect a hefty dose of caffeine to at least speed up the heart, but that didn't happen here. What did happen was that the caffeine group showed a slightly higher strength gain compared to those consuming the placebo. Most
studies that examine the ergogenic effects of caffeine find it increases endurance. Researchers believe that the substance may exert a glycogen-sparing action because it stimulates fat release. The mechanism here is increased epinephrine as a result of caffeine ingestion.
Epinephrine, secreted from the adrenal glands, is a fight-or-flight stress hormone that marshals body mechanisms, which results in increased energy and power-at least temporarily. The famous case of the 123-pound woman who lifted one end of a 6,000-pound car that had fallen on her
son is a graphic illustration of the potent effect of a sudden, massive release of epinephrine. In addition, the martial arts practice of inducing i, a sudden increase in power, is thought to work by somehow increasing epinephrine release. In the case of caffeine triggering increased
epinephrine, the epinephrine then turns on a fat-releasing enzyme called hormone- sensitive lipase. The entire effect is canceled, however, if carbohydrates are consumed with the caffeine.
In the strength study reported here, the caffeine effect was again probably due to increased epinephrine, although it has nothing to do with increased fat release. Another possibility is that caffeine increases the rate of entry of calcium into a portion of muscle cells called the
sarcoplasmic reticulum, which would enhance muscular contraction.
Besides increasing strength, caffeine exerts a mild diuretic action and increases basal metabolism by about 10 percent. It reaches a peak blood level in 30 minutes, and the ergogenic dose is between 250 and 350 milligrams. At doses above 250 milligrams, however, some people experience
such side effects as nervousness, insomnia and tremors. The lethal dose is between three and 10 grams, and death is caused by heart rhythm disturbances or seizures.
If you contemplate training twice a day, you'd better pay attention to carbohydrate intake, according to a study released by Ball State University in Indiana. Intense training depletes muscle glycogen, a form of stored complex carbohydrate that's the primary fuel for anaerobic
exercise, such as the typical bodybuilding workout. Lack of adequate glycogen replenishment leads to decreased muscle recovery between training sessions. The study examined the effects of ingesting various forms of carbohydrate on muscular endurance. The subjects consisted of seven
endurance-trained male cyclists who performed two workouts: an anaerobic cycling workout followed by an aerobic workout.
One hour after the anaerobic session the subjects consumed one of four carbohydrate sources in an amount calculated to provide 1.5 grams of carbohydrate per kilogram of bodyweight per hour over a four- hour period. The carb sources included an energy bar; a commercial liquid carb
drink; and soft, semi- moist carbs in the form of Snack- wells and Fruit Newtons cookies. The subjects trained again six hours after the first workouts.
All the carb sources proved more effective than water-which is certainly no surprise. As for the various types of carbs the Snackwells and Fmit Newtons showed the best energy release. The researchers concluded that consuming carbohydrates between anaerobic and aerobic workouts
improves exercise performance.
How Important Is Protein Quality for Fat Loss?
Statistics show that most weight loss regimes ultimately fall because the dieters return to previous body- fat levels. The word for this is 'recidivism," and the current rate for recidivism is estimated at 97 percent. There are several reasons why so many diets fail, the first one
being that dieters don't exercise. Although this isn't as common as it used to be, some people believe that all you need to do to lose weight is go on a lower-calorie diet. This type of weight-loss philosophy is doomed. As noted in an extensively publicized study done at Rockefeller
University in New York a few months ago, your body has a weight set point that it adjusts to after you gain or lose weight. This means that when you lose weight solely through dieting, your metabolism decreases in proportion to the amount of weight lost.
In short, as you lose weight, you need less calories, so if you increase calories after you get to your weight goal, you end up in the 97 percentile of diet failures. It's not difficult to understand why so many people regain the weight; most folks don't have the willpower to eat
limited amounts of food for the rest of their lives. You may recall the initial failed diet efforts of talk show host Oprah Winfrey. After going on a liquid protein diet, Oprah proudly announced on her show that she'd lost 57 pounds and regained her self-esteem in the process. She
punctuated these remarks by wheeling out a wheelbarrow containing 57 pounds of fat. It was a depiction even more startling than a typical Oprah theme show involving transvestite husbands.
Oprah quickly regained her lost weight, however, and in the process she became even more rotund than before. When it got to the point that she was making Roseanne look slim, Oprah began dieting again. This time, though, she exercised more. Oprah has thus far retained her newfound
svelte shape, hut she could be making another mistake.
According to some written sources, Oprah runs regularly and has even completed a marathon- but she doesn't lift weights. If this is true, then you can expect her to regain that lost fat once more. Although aerobic exercise increases the metabolism while you're doing it, it does
nothing to change the underlying metabolic problems that are the root of most people's excess fat. Weight training, on the other hand, maintains lean mass, or muscle, during dieting far more efficiently than any type of aerobics. Aerobic exercise doesn't prevent the metabolic
slowdown that occurs with dieting. The only way to do this is to maintain muscle. There are other critical aspects of dieting that are frequently overlooked. As you decrease calories, you must increase protein consumption to maintain your lean mass, hut people often make the mistake
of decreasing calories across the board; that is, they lower their intake of fat, carbohydrate and protein. The muscle loss that results sets you tip for a probable weight regain, a dieting cycle some researchers refer to as the yo-yo effect.
One question that isn't usually discussed, however, is that of protein quality, Can such factors as the biological value of various protein sources make a difference in your diet?
Most bodybuilders accept the need for high-quality protein sources while dieting as an undeniable fact. Canadian researchers recently tested the effects of different quality protein under extreme low-calorie conditions, and they reported the results in the International Journal of
Obesity. The study examined the effects of two types of protein sources during a diet of less than 1000 calories a day. This is commonly associated with nitrogen, or protein, losses. The protein sources examined included a milk protein, or casein and soy source, and a collagen-based
The milk-soy protein was considered the higher-quality protein source because of its higher essential amino acid content of 46 percent. The collagen protein, in contrast, contained only 16 percent essential amino acids. Both sources supplied 93 grams of protein.
Since collagen is a naturally unbalanced protein because it lacks sufficient amounts of certain essential amino acids, the missing aminos were added to the collagen. Even with the added aminos, however, the collagen was still clearly inferior to the milk-soy source. The results
showed that both protein sources maintained the nitrogen equilibrium and lean body mass during the first four weeks. By the sixth week protein synthesis had decreased in the subjects who were on both diets, but protein breakdown decreased only in the milk-soy protein group.
The collagen group was now in negative nitrogen balance, and they were losing muscle.
The short-sighted conclusion of this study was that protein sources are irrelevant during the first few weeks of dieting and that it's simply important to get enough protein in your diet. After the six-week mark, however, higher-quality proteins will serve to more efficiently
maintain lean mass-which means that we bodybuilders were right all along. Protein quality does indeed make a difference.