In Part 1 and Part 2, David and Cassandra summarized dozens of new studies presented at the ACSM's annual conference. In this final installment, John Berardi will cover the interesting abstracts related to muscle physiology, muscle metabolism, hormones, weight loss, and nutrition.
Part 1: Up On My Soapbox – Energy Balance
I'd like to begin with a review of the best science conference I've attended since I started going to these things.
Energy Balance – A New View For Weight Loss and Athletic Performance
In this talk, Drs. Benardot, Granata, and Martin discussed the results of their research program focusing on helping athletes maximize their meal timing in an effort to enhance body composition and performance. Their laboratory at the University of Georgia has developed a technique known as computerized time line energy analysis (CTLEA) in which hourly energy balance estimates are calculated.
They believe that while most view energy balance with 24-hour endpoints in mind (i.e. energy balance is achieved when 2000kcal are expended and 2000kcal are ingested at the end of the day), it's more important to recognize that daily energy balance can be achieved with wildly differing patterns of hourly energy balance.
In the charts below, the red arrows represent meals (energy intake) while the black arrows represent exercise (energy expenditure). Check it out:
As you can see, while all three scenarios won't produce a huge daily calorie surplus or deficit, they do produce different hourly energy balance calculations. Using this model to determine hourly energy balance, the authors have shown that by eating frequently and eating for the activities you've just done as well as the activities you're about to do, you can dramatically improve body composition without even changing dietary composition or daily energy balance. (Of course, if you go ahead and make better food choices you'll see even bigger improvements).
The authors suggest that if you want to best improve body composition, keep your hourly deficit or surplus to within plus or minus 300 to 500kcal. This means that if you were to graph accumulated energy status, as seen above, you should never be more than 500 kcal above or below the zero point.
These suggestions are based on data showing that frequent eating can improve glucose tolerance, decrease the insulin response to meals, decrease blood cortisol, decrease serum lipids, decrease adipose tissue, and maintain metabolic rate. In addition, their studies on gymnasts and runners have shown that the athletes with the largest and most frequent hourly energy deficits were the fattest, while the individuals with the smallest and least frequent deficits were leanest.
Their work also shows that when adding three daily snacks (an addition of 750kcal per day) to a three meal per day plan (while maintaining hourly energy balance numbers as discussed above), the snack group lost fat, increased lean body mass, increased vigor, anaerobic power, and endurance.
Interesting stuff! Especially since it goes right along with what I've been saying all along – macronutrient type and timing really matters!
Part 2: Protein Needs in Athletes
In this symposium, Dr. Tarnopolsky and colleagues discussed a number of studies examining how protein interacts with training to lead to increased strength, mass, and performance. While most of the data discussed in this talk is probably old hat to the T-mag audience, I wanted to bring up an interesting list that Dr. Tarnopolsky provided.
In response to his discussion of the protein needs in athletes, Dr. Tarnopolsky provided a list of factors one needs to know to decide just how much protein he needs. One look at this list illustrates just how complex this area is. Here are the factors:
• State of Training (Beginner, Intermediate, Advanced)
• Intensity/Duration/Frequency of Training
• Other Sports Participating In
• Total Carbohydrate Intake
• Total Energy Intake
• Biological Value of Ingested Proteins
• Hydration Status
So next time someone tells you how much protein you really need without knowing these variables, kick 'em in their amino acids for me!
Part 3: More Studies
Since you're probably all "researched out" from the last two articles, I thought I'd give you a quick, down and dirty look at the abstracts I found interesting at ACSM. Since I'm batting clean up, I've got a bunch more abstracts to cover than Dave and Cassandra. So rather than review each study in detail, I'm just gonna' hit ya with a news flash and then give an important line or two about each one.
1) Post-workout nutrient supplements cause diabetes! (Abstract #471 – Bosher, et al.)
Okay, I know Cassandra already beat up on these guys but I've gotta get in my digs as well. In this study the authors gave subjects either high fat, high carb, or placebo meals after exercise and measured insulin, glucose, and triglyceride concentrations. Due to the large increases in insulin and glucose in the carb group and triglycerides in the fat group, the authors concluded these meals could create an environment that could promote diabetes and/or arteriosclerosis.
Geez, guys, with that logic, perhaps all eating promotes diabetes and CVD. Maybe we should just stop eating altogether!
2) Whey protein and casein protein both increase protein synthesis after exercise. (Abstract #556 – Cree, et al.)
In this study, 20 grams of whey protein and 20 grams of casein protein were given one hour after strength training (leg exercise). Both proteins promoted large increases in phenylalanine and leucine uptake (markers of muscle protein synthesis) over several hours post-exercise.
So, both whey and casein are probably good for increasing post-exercise protein synthesis. Of course, to maximize this response, the drinks should be given pre/during exercise and immediately post-exercise.
3) Postmenopausal women benefit from post-workout nutrition. (Abstract #557, Holm et al.)
While we know that in young, healthy subjects, post-workout nutrition is beneficial, this study demonstrates that the benefits of post-workout nutrition know no bounds. When given 10 grams of protein and 29 grams of carbs, women (mean age 56) had greater post-strength training increases in protein balance vs. a placebo group.
4) Get drunk after exercise for increased free Testosterone? (Abstract #1833, Vingren eat al.)
Gosh, it hurts me to present these data. Apparently, for five hours after a 45-minute whole body strength training routine, free Testosterone concentrations are higher when ethanol is consumed immediately after training than when no ethanol is consumed. That's right, after training there usually is a decline in free T over the next five hours. When consuming alcohol, this doesn't occur. Even more interestingly, the drunken boys even had higher Testosterone concentrations after exercise than when they were sober and not exercising at all.
Before you go adding some vodka to your Surge, remember that the authors actually made these subjects intoxicated (mean blood alcohol > 0.1g/dl) and that these results aren't the case for total T. Finally, as you might imagine, there are other repercussions to getting soused after each workout.
5) Training increases resting muscle protein synthesis, but reduces post-exercise protein synthesis. (Abstract 1911, Kim et al)
In this study, the researchers had subjects train one leg three times per week while the other leg remained untrained. After four weeks, the trained leg was bigger and the resting protein synthetic rates in this leg were higher than in the untrained leg. However, post-exercise protein synthesis was lower in the trained leg vs. the untrained. This may further highlight the need for proper post-workout nutrition in trained individuals.
Carbohydrate Supplements and Exercise
1) Adding fructose or sucrose to glucose supplements increases carbohydrate oxidation in endurance athletes. (Abstracts #818 and 1169, Jeukendrup et al and Jentjens et al)
Endurance athletes can benefit by consuming carbohydrates during exercise. Previously calculated maximal rates of exogenous carbohydrate oxidation have been estimated at 1g/minute indicating that endurance athletes wouldn't benefit from more than 60 grams of carbohydrate per hour. In these two studies, the authors hypothesized that since different intestinal transporters take up different carbohydrates, a combination of carbohydrates might improve carb uptake and oxidation rates.
They were correct! Exogenous carbohydrate uptake may be improved when sucrose and/or fructose are added to a glucose drink. When this is done, maximal oxidation rates approach 1.25g to 1.3g/minute or 75-80g/hour.
1) Creatine phosphate works as well as creatine monohydrate in increasing body mass. (Abstract #1202, Eckerson et al)
In this study, subjects received 5g of creatine citrate with the addition of 2g of potassium phosphate, 2g of sodium phosphate, and 18g of dextrose for 30 days. During this time, subjects gained about 1kg of body mass, a similar mass gain as seen in creatine monohydrate studies.
2) Creatine supplementation is safe for the kidneys. (Abstract #2238, Boswell et al)
In this study, the authors supplemented subjects with creatine (five days of loading and 23 days of maintenance). During this time, measures of glomerular filtration, serum urea nitrogen, creatinine, electrolytes, osmolality, hemoglobin, and hematocrit showed no changes with creatine supplementation or placebo supplementation.
Since all subjects did exercise (whether in placebo or creatine group) an interesting observation emerged: exercise decreased glomerular filtration rates by 10% and increased serum creatinine concentrations by 20%. So if you do go to the doc and he finds increased serum creatinine, don't let him tell ya it's from your high protein diet or from your creatine supplementation. It's just an effect of your training.
3) Creatine supplementation plus whey protein is superior to creatine and carbs or whey alone. (Abstract #2239, Cribb et al)
In this study, subjects strength trained for 11 weeks and received either creatine plus carbohydrate, whey protein, carbohydrate alone, or creatine plus whey protein. While all groups increased muscle cross sectional area, total lean mass, and muscle strength, the whey protein and creatine group did better than the whey group, which did better than the creatine and carb group and carb group alone. Interestingly, the increases in muscle cross sectional area correlated well with the strength gains.
4) Creatine supplementation slows muscle atrophy when immobilized. (Abstract #2242, Bull et al)
Subjects in this study had the unenviable task of having their arms put in casts for seven days. During this time, they got either a placebo treatment or 20g of creatine per day. Casting resulted in large losses in lean mass and strength in the placebo group (-4% lean mass, -29% 1RM biceps curl, and –46% max reps for biceps and triceps exercises).
In the creatine group, no lean mass was lost (+0.17%) while only small reductions in 1RM strength (-6%) and muscle endurance (-5% were seen).
1) If you've got muscle soreness, don't take NSAIDs. (Abstract #38, Lapointe et al)
It almost seems logical to suggest that anti-inflammatory drugs would be beneficial during DOMS (Delayed Onset Muscle Soreness). However, I say "almost" because more and more studies are showing that NSAIDs (nonsteroidal anti-inflammatory drugs) can actually interfere with the adaptation to exercise training.
This study showed that while NSAIDS were beneficial in more quickly restoring muscle function after a single bout of highly damaging eccentric exercise, they do interfere with the adaptation to this type of exercise, preventing the normal reductions in damage seen during future bouts.
2) Proteases (digestive enzymes) like trypsin, bromelain, papain, and amylase decrease DOMS. (Abstract #1100, Miller et al)
In this study, subjects were given 325mg of pancreatic enzymes, 75mg trypsin, 50mg papain, 50mg bromelain, 10mg amylase, 10mg lipase, and 10my lysozyme or 1000mg of acetaminophen four times per day for four days. During this time, subjects ran at a 10% downhill grade for 30 minutes. With the protease supplementation, it appeared that muscle soreness was less severe when compared to the acetaminophen treatment, indicating that protease supplementation may have anti-inflammatory effects.
3) Red pepper supplements increase whole body and skeletal muscle metabolism. (Abstract 1385, Ueda et al)
Red hot pepper has metabolic properties in that one gram of dried red pepper powder can increase overall body oxygen consumption by 10% and muscle oxygen consumption by 15% during the 150 minutes after red pepper ingestion. In addition, sympathetic nervous system activity is increased with red pepper consumption. This may make red pepper a safe and effective thermogenic supplement.
4) Fish oil supplements increase metabolic rate. (Abstract 1388, Noreen et al)
My lab mate, Eric Noreen, presented a nice study showing that supplemental fish oil can increase metabolic rate and decrease blood triglyceride concentrations. In his study, Eric supplemented subjects with 9g of safflower oil (high omega 6), 3g of concentrated (60%) fish oil, 6g of concentrated fish oil, or 9g of concentrated fish oil.
The safflower oil group saw decreases in metabolic rate while the fish oil groups all increased metabolic rate by anywhere from 141 to 448 kcal per day. In addition, small decreases in fat mass accompanied by small increases in lean mass were seen with fish oil supplementation.
5) Synephrine increases resting metabolic rate without increasing heart rate or blood pressure. (Abstract #1389, Seifert)
Synephrine, or citrus aurentium, is a popular fat loss supplement. In this study the authors examined its ability to increase metabolic rate in the mildly obese. With synephrine supplementation, metabolic rate was increased by 8% while increases in oxygen uptake were also seen. No changes in heart rate, blood pressure, or fuel utilization were observed.
6) For performance benefits, caffeine need only be ingested in the morning. (Abstract # 1476, Bell et al)
It's well known that caffeine supplementation increases performance. In this study the authors were curious as to whether caffeine would have to be ingested before each bout of exercise if more than one were to be performed in a single day. Answer: nope. Caffeine (5mg/kg) need only be consumed prior to the first bout of the day if another is to be performed later.
7) Panax Ginseng improves endurance and oxygen uptake. (Abstract #1486, Liang et al)
In this study subjects were given 450mg panax notoginseng or placebo three times per day for 30 days. During a constant load exercise test, the ginseng group exercised for longer after supplementation while the placebo group did not. In addition, oxygen uptake and ventilation was lower for the same workload in the ginseng group after supplementation.
8) Oxygenated water: Worthless in hypoxia. (Abstract # 1488, Porcari et al)
Drinking oxygenated water has been suggested to improve exercise performance. In this study, the authors induced hypoxia by inhaling a low oxygen mixture and measured whether blood oxygenation or heart rate would be improved during hypoxia when oxygenated water was ingested. The simple answer: oxygenated water offered no benefit.
9) HMB still reduces muscle soreness and damage. (Abstract #1498, van Someren)
While everyone here hates HMB, I've reported before that it still does offer some benefit in terms of reducing soreness and muscle damage. Here I am again to say the same thing. In this study, 3g of HMB was given for 14 days and eccentric exercise was performed to make the participants sore. As shown before, muscle damage and soreness were decreased 24 hours after exercise with the HMB group.
10) GABA increases GH release after exercise. (Abstract #1500, Powers et al)
GABA is a neurotransmitter that plays a role in GH release. When given at a dose of 3g prior to strength exercise, subjects get a larger increase in GH secretion when compared to placebo treatment. Unfortunately, this effect isn't present at rest.
11) Whey and casein supplement is superior to whey and BCAA plus glutamine supplement for increasing lean mass. (Abstract #2205, Kreider et al)
During ten weeks of strength training, subjects received 48g of carbohydrate per day, 40g whey plus 8g casein per day, or 40g whey plus 3g BCAA plus 5g glutamine per day. The whey plus casein group observed greater gains in total mass and lean mass during the training when compared to the whey plus amino acids and the carbohydrate group.
1) Weight training causes reperfusion injury and oxidative stress. (Abstract #525, Uchiyama et al)
A while back, Lonnie Lowery and I proposed that weight training could induce ischemia reperfusion injury (i.e. blood flow occlusion occurs during intense contraction and upon subsequent reperfusion of blood, oxidative stress occurs). In this study, the authors confirmed this in rat skeletal muscle by measuring muscle damage and antioxidant enzyme activity after an exhaustive strength exercise bout. These data suggest that oxidative stress does occur with weight training and that the body upregulates antioxidant activities to compensate.
2) A combination strength training and aerobic program reduces oxidative stress in humans. (Abstract #533, Jamurtas et al)
Exercise is known to produce free radicals and produce oxidative damage. The reason it's still recommended is because the body can upregulate antioxidant status in order to compensate for this excess free radical production.
In this study, inactive older adults were trained 16 weeks by doing aerobic exercise, strength exercise, or a combination of both. While weight training promoted some positive effects, the combined group saw improvements in oxidative stress and antioxidant status. In fact, in these groups, the net oxidative stress measures were improved vs. the pre-study, sedentary measures. This means that chronic exercise may protect individuals from some of the negative effects of aging.
3) Sesamin is a powerful antioxidant in exercise and smoking. (Abstract #1489 and 1490, Kiso et al and Moritani et al)
Sesamin is one of the lignans found exclusively in sesame oil. Once in the liver, sesamin is converted to a strong antioxidant. In the first study, rats had lower rates of lipid peroxidation (free radical damage) with sesamin supplementation vs. placebo and vitamin E supplementation.
In the second study, sesamin was given to smokers after a single exposure to smoking. While the placebo group had increases in heart rate, cardiac sympathetic nervous activity and a reduction in parasympathetic activity, sesamin showed a reduction in these changes. In addition, changes in ECG were seen with smoking and placebo while sesamin prevented these. In all, sesamin might prevent some of the adverse cardiovascular effects of smoking.
4) Antioxidant supplementation reduces protein oxidation with downhill running. (Abstract #1492, You et al)
Downhill running is a severe form of eccentric exercise. This type of exercise results in some serious DOMS. In this study, rats exposed to 90 minutes of downhill running had large increases in markers of protein oxidation in both fast twitch and slow twitch muscles. Two weeks of vitamin C and vitamin E treatment reduced some of this protein oxidation.
Body Fat, Weight Loss, and Health
1) Fatness, not fitness is the best predictor of cardiovascular disease risk. (Abstract #355, Christou et al)
Many scientists have wondered whether overall body fat levels or overall fitness levels were more important for disease risk. In this study, a host of risk factors for cardiovascular disease were measured in 141 healthy men.
Overall body fatness was closely correlated with every major metabolic, hemostatic, and lipid risk factor while low fitness was only correlated with a few measures. Waist circumference was one of the biggest predictors, correlating as well as overall body fat with most of the risk parameters.
So, T-men, listen up. Just because you workout a few days a week doesn't mean you're in the clear. Body fat has to be controlled in order that your exercise have any benefit with respect to cardiovascular disease risk.
2) Abdominal adiposity not only predicts cardiovascular disease risk, it also predicts insulin action. (Abstract 366, Racette et al)
In this study, 254 men and women were measured for insulin action (insulin sensitivity), fitness, and abdominal fatness. In the end, both fitness and abdominal fat were well correlated with insulin action, with a simple waist measurement being the strongest predictor of insulin insensitivity. Again, if you're not lean, all that weight training won't protect you from cardiovascular disease and insulin resistance.
3) Surprise, surprise. More exercise equals more fat loss. (Abstract #578, Jakicic et al)
While "overtraining" has been a topic of considerable importance over the last few years, it's my opinion that many have taken this idea to the extreme, doing far too little exercise to see excellent body composition changes.
In this study, researchers measured the weight loss and fitness effects of different doses of exercise on 184 sedentary women. When three groups were compared (>200 minutes of exercise per week, 150-200 minutes per week, <150 minutes per week), the group that did the most exercise had the greatest weight loss and best fitness. This amount of exercise equates to about 30 minutes per day. Heck, most weight trainers I know, especially those of the HIT variety, barely do that much.
4) Adipocyte adrenergic receptors related to body fat response to training. (Abstract #1029, Phares et al)
Without killing you with a genetic and sub-cellular discussion, I'll sum this study up by saying this: it's important to note that there are receptor issues that impact the rate of fat loss both overall and in certain areas of your body. When certain adrenergic receptors are present on your fat cells, fat loss is easier than when others are present. This might explain why some individuals are very fat loss resistant and others lose fat easily on the same type of dietary plan.
Energy Expenditure and Exercise
1) Strength training has a significant metabolic cost. (Abstract #1002, Glowacki et al)
In this study, total oxygen consumption, respiratory exchange ratio (a measure of fuel utilization), and estimated calorie cost were determined during and after a strength exercise session consisting of nine exercises performed using three sets of ten reps at 70% of 1RM (total of 27 sets). This exercise session cost approximately 375 kcal while one hour post-exercise energy cost was 77 kcal. Fuel utilization during exercise was predominantly carbohydrate (RER=1.0) but post-exercise RER reflected a shift toward fat burning (RER=0.82).
2) Circuit training increases post-exercise metabolism vs. treadmill exercise. (Abstract #1005, Braun et al)
In order to determine the EPOC (post exercise elevation in metabolic rate) of treadmill exercise vs. circuit training, eight women performed each exercise session (matched for duration and energy expenditure) and post-exercise oxygen consumption was measured. In the end, circuit training was associated with a greater post-exercise metabolic cost during the first 60 minutes of the post-exercise period.
1) Growth hormone releasing hormone therapy enhances body composition, exercise capacity, and functional performance in older women. (Abstract #1364, Frick et al)
In this study, 1mg of recombinant GHRH (1,44-Amide) per day was administered to older women. After three months of therapy, improvements were seen in thigh muscle mass, abdominal fat, total fat free mass, total fat mass, and a number of measures of fitness and functional performance (i.e. stair climbing, flexibility, etc).
2) Increased protein can reduce the decline in IGF-1 associated with training and calorie restriction. (Abstract #1365, Nindl et al)
IGF-1 declines with underfeeding, overtraining, and protein inadequacy. In this study, Marines received either a high protein diet or a low protein diet during an eight day field exercise consisting of intense physical activity along with sleep deprivation. While the low protein subjects saw a large decrease in IGF-1 during the eight days, the high protein subjects had a better maintenance of IGF-1.
3) Homocysteine concentrations are elevated with long-term steroid use. (Abstract #1477, Grace et al.)
In this study, steroid using weightlifters were shown to have higher blood concentrations of homocysteine and a higher hematocrit. Since homocysteine is a protein that may irritate blood vessel linings, it's been linked to atherosclerosis.
While this doesn't bode well for steroid users, the encouraging finding in this study is that those subjects who had terminated steroid use three months prior to testing had no evidence of increased homocysteine in the blood. However, even brief periods of steroids may put someone at increased risk for atherosclerosis.
There you have it, the 2003 ACSM annual meeting summarized in three parts. And next year's meeting is bound to be even bigger! In 2004 I might have to recruit a few more contributors to help get through the book of abstracts! Hope you learned something!