2009 Studies & Research Blog

For individuals with diabetes, regular exercise is one of the top ways they are recommended to help cope with their condition. Performing exercise on a regular basis can help keep their bodyweight under control, which is a significant factor influencing the severity of their condition, can keep blood pressure down, and can help moderate blood sugar levels.

It’s important for those with diabetes to be especially careful with their carbohydrate intake around the workout period because they are at an increased risk for experiencing a severe blood sugar level crash, but provided they have help from their doctor with this most can adjust their intake accordingly.

When it comes to the exercise portion of the equation, just how intense does the exercise need to be to be beneficial?

That’s what some researchers out of the University of Brussel in Belgium wanted to assess. The aim of their study was to look at the impact of exercise intensity on lowering blood HbA(1c) levels in type 2 diabetic patients who were classified as currently obese.

The study was set-up so that 6 months of continuous low to moderate exercise was performed and then compared with moderate to high intensity exercise for the same period of time.  Both types of exercise sessions were matched in terms of energy expenditure, therefore it was only the actual intensity that differed between the trials.

These exercise sessions either consisted of 55 minutes, 3 times a week at 50% of their whole body peak oxygen uptake, or 40 minutes at 75% of this value.  

After the exercise was completed, oral glucose tolerance, blood glycated haemoglobin, lipid profile, body composition, maximal workload capacity, and whole body and skeletal muscle oxidative capacity was assessed.  

The results of the study demonstrated that after the 6 month time period no differences were demonstrated between groups, with both groups showing reduce blood glycated haemoglobin levels, decreased LDL-cholesterol concentrations, lowered body weight and leg fat mass, and increased muscle mass.  

So, from this study we can conclude that if you are suffering from diabetes and are overweight looking to get in shape, don’t think that you have to be working at an extremely high intensity to reap benefits. You can definitely get great results from a more moderate exercise program which will likely be a lot more comfortable for you to get started with.

Even for individuals without diabetes, any form of exercise will have health benefits, so don’t let a fear of exercise being a painful process prevent you from getting started.  Work your way into it in a manner you’re comfortable with and enjoy the health benefits as you go along.

Reference:

Berger, J. et al. (2009) Continuous low-to-moderate intensity exercise training is as effective as moderate-to-high-intensity exercise training at lowering blood HbA(1c) in obese type 2 diabetes patients.

The benefits of protein in muscle-building, via the contribution of amino acids, and fat loss, thanks to a high thermic effect, are common knowledge among the fitness community.  But this amazing macronutrient has a variety of other benefits that are unknown to many, and more are being discovered all the time.  For instance, a recent study from the Medical College of Georgia revealed that certain types of protein can actually help scientists identify cases of prostate cancer.

The study, published in the Early Edition of the Proceedings of the National Academy of Sciences, identified the beta-Arrestin2 protein as a way for scientists to assess whether cancer cells are developing in male reproductive organs, notably the prostate.  Additionally, increasing beta-Arrestin2 levels in the prostate may aid in the fight against prostate cancer for those who have the deadly disease.

According to the researchers, prostate cancer initiation and development is a result of an increase in androgen receptors in the prostate.  The increase in androgen receptors allows the cancer to develop by utilizing as much of the body’s available testosterone as possible.  Androgen receptors can also mutate, developing the ability to feed off of other growth factors in the body.  Because of this adaptability, prostate cancer is one of the most difficult cancers to defeat.

The researchers found that androgen receptors and beta-Arrestin2 seemed to have a relationship; when there was an abundance of androgen receptors, as in a cancerous prostate, there were low levels of beta-Arrestin2.  Thus, the researchers reasoned that the opposite would be true and tested the hypothesis by forcing an increase in beta-Arrestin2 levels.  The results were as expected - higher levels of beta-Arrestin2 suppressed the activity and expression of androgen receptors.

While this discovery alone is not enough to defeat prostate cancer, it does open the door for possible treatments, and could change the way prostate cancer is classified.  Additionally, the development of a treatment in the form of a molecule mimicking beta-Arrestin2’s suppression of androgen receptor activity is a goal of the researchers.

And while supplementation of beta-Arrestin2 isn’t an option at this point, this research shows that protein isn’t just for bodybuilders and fitness enthusiasts.  While amino acids do play an essential role in building muscle, cellular proteins keep the body functioning at all levels and are much more than simply a source of calories.

SOURCES:

1. Daaka, Yehia, et al. Identification of beta-Arrestin2 as a corepressor of androgen receptor signaling in prostate cancer.  Proceedings of the National Academy of Sciences Online Early Edition, 2009; 10.1073

2. Medical College of Georgia (2009, May 20). Protein That Suppresses Androgen Receptors Could Improve Prostate Cancer Diagnosis, Treatment. ScienceDaily. Retrieved May 26, 2009, from http://www.sciencedaily.com­ /releases/2009/05/090520100513.htm

Getting the right exercises, total set number, and number of reps in your workout is going to be vital so that you see continued results.  Far too often though people overlook the factor of tempo.  How fast or how slowly you lift a given weight will have a direct influence on how you progress as well, as it will factor into the total intensity of the weight lifting program.

As you may have already found out for yourself if you’ve experimented with different tempos, lifting a weight at a much slower pace does tend to be significantly more difficult than lifting it at the typical moderate pace instead.

Recently, researchers out of the Waseda University wanted to assess tempo and the resulting hormonal responses different protocols obtained.

The design of the study was set up so that nine men would perform knee extension exercises.  On one occurrence they would perform these at a low-intensity with a clow concentric contraction, with a rate of 5:1 seconds on the concentric to eccentric phase.  

On the second occurrence they would perform similar low-intensity exercise with slow eccentric contractions, reversing the ratio to 1:5 seconds for the up and down motion.

On the third trial, they were to maintain similar timing for both the eccentric and concentric contractions, with a 3:3 ratio.  

Finally, on the fourth trial they performed high-intensity exercise at the normal velocity of 1:1 for contraction speed.

After each trial the subjects were tested for lactate concentration, plasma ephinephrine, serum growth hormone, and free testosterone levels.  

The results of the study indicated that the lactate concentration in the body was significantly higher after the 5:1 exercise compared to the 1:5 exercise.  The slow movement exercises also showed a much higher level of serum growth hormone and free testosterone concentration compared to the faster paced tempo.  One interesting thing to note was that serum cortisol level was higher after the 5:1 tempo compared with the 1:5 or 1:1 tempo.

From this data we can conclude that there are some positive muscle building correlations between performing slower weight lifting contractions, however to avoid higher cortisol levels throughout the body you would be better off not just focusing on slowing down the concentric portions of the movement.

Reference:
Goto, K, et al. (2009) Hormonal and metabolic responses to slow movement resistance exercise with different durations of concentric and eccentric actions.  European Journal of Applied Physiology. May 10.

Enter any gym in America and you’re bound to see two things, regardless of location - sweaty people and sports drinks.  Beverages such as Gatorade and Powerade are everywhere, boosted by celebrity endorsements from the likes of Tiger Woods, Vince Carter and Michael Jordan.  While an infusion of simple carbohydrates is undoubtedly helpful for athletes engaging in long bouts of high-intensity exercise, are sports drinks effective, or even appropriate, for the average gym-goer?  Studies seem to be split on the matter.

Recently, a study indicated that the most maligned ingredients in most sports drinks, simple sugars (such as glucose and maltodextrin), were actually a key to their effectiveness, regardless of whether they were digested or not.  Researchers prepared beverages containing glucose, maltodextrin or neither, so that they tasted identical, and gave them to athletes, who rinsed the drinks around in their mouths before spitting them out during exercise.  Despite not reaping the energizing effects of the carbohydrates in the drinks, the rinsing of the simple sugar mixes were shown to "significantly reduce the time to complete the cycle time trial," while the placebo drinks had no such effect.  The data was so impressive that the researchers concluded that "much of the benefit from carbohydrate in sports drinks is provided by signalling directly from mouth to brain rather than providing energy for the working muscle" (1).

However, simple sugars carry concerns as well, such as the risk of tooth decay. But it’s not just the sugars in sports drinks that increase this risk, researchers recently concluded.  The New York University School of Dentistry found that citric acid, commonly found in sports drinks, ate away at the enamel coating on teeth.  As a result, the drinks could easily leak into the bone-like material underneath, causing a weakening and softening of the tooth that could "result in severe tooth damage and even tooth loss if left untreated" (2).

So should you be drinking a carbohydrate-containing beverage during your workout?  There’s no clear yes or no answer.  If you’re trying to lose weight, it’s probably not the best idea, as liquid calories are unlikely to leave you sated and may negate the caloric deficit created by the exercise during which they were consumed.  But even those in mass-gaining phases may find them unnecessary.  Research indicates that the most important consideration may be the length of exercise.

According to researchers at the University of New Mexico, "unless a person is going to exercise for at least 90 minutes, consuming the carbohydrates is self-defeating."  While sports drinks containing carbohydrates may aid the body in absorbing water, there is no evidence that the body actually retains the water more effectively than if water were consumed on its own, and therefore is not more effective at battling dehydration (3).

SOURCES:

1. Chambers, E.S.  Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity.  The Journal of Physiology, 2009; 587: 1779-1794.

2. NYUCD Study Finds Sports Drink Consumption Can Cause Tooth Erosion.  NYU Office of Public Affairs; April 7, 2009.

3. Felicia Fonseca. Study: Gatorade No Better Than Water. New Mexico Daily Lobo; March 4, 2004.

At one point or another, almost all of us overeat.  It could be at Christmas, at Thanksgiving, after a long and hard week where you just used food for comfort, or some other factor, but there’s a good chance that after that period of overeating, you felt at least somewhat guilty.  You may have worried that you’d set yourself back – undone all the hard work you just put in the previous week and are now starting the week over again.

Is this really the case though? And, is there anything you can do to offset this overfeeding?

Researchers out of the University of Massachusetts wanted to assess what the influence of an energy surplus was in terms of circulating concentrations of leptin, insulin, and ghrelin.  Leptin is a hormone in the body that senses current body fat stores and energy intake, working to regulate hunger and the metabolic rate in the body. Insulin is the primary hormone that is released when you consume carbohydrates, working to take the glucose into the muscle cells.  Finally, ghrelin is another hormone that works with leptin to stimulate hunger and is produced by the fat cells.  When it is present in the body in high concentrations, you will feel a great deal hungrier and be stimulated to eat.

When you consume more calories than you typically do, this energy surplus will raise the concentrations of leptin and insulin in the body while decreasing the concentrations of ghrelin.  When you exercise, the exact opposite occurs.

Therefore, the researchers wanted to observe whether exercise could counter the hormonal effects of the energy surplus regardless of energy balance.  They first assessed the plasma concentrations of all three hormones at baseline and then after an overfeeding period, and finally, after an overfeeding period that was accompanied by exercise.

The overfeeding process took place over a three day period total, where they were overfed by an amount of 3213 +/- 849 kJ/day after coming off a two day period of maintenance eating. For the exercise group, an equal net energy surplus was generated for 24 hours by doubling the overfeeding amount and countering it with an exercise sessions that burned the number of calories to make both situations equal again.

After the test was taken, when looking compared with baseline, leptin levels went up after the overeating group without exercise but was not significantly higher after the overeating plus exercise group. Additionally, insulin levels were higher in both overfeeding without exercise and overfeeding with exercise.  Lastly, overfeeding without exercise had no impact on the ghrelin concentrations in the blood, however the overfeeding plus exercise group actually lowered them.

From these results we can see that the impact of overfeeding on leptin and insulin levels does depend upon energy balance, however the ghrelin response to overeating can be counteracted by exercise.

While you should never use exercise as a way to ‘compensate’ for chronic overeating as that can lead to a number of problems, both physical and psychological, this study does suggest that you can offset some of the impacts of overeating by partaking in exercise after.

Reference:

Braun, B., Hagobian, TA., & Sharoff, CG. (2008) Effects of short-term exercise and energy surplus on hormones related to regulation of energy balance.  Metabolism. Mar;57(3):393-8.

With the recent recall of Hydroxycut and the suspension of several NFL players due to their use of a weight-loss supplement, dietary aids have come under a lot of fire within the past few months.  Unfortunately, most of the general public is not very educated on this subject, and media reports can be exaggerated and blown out of proportion, leading the average consumer to think that all weight-loss drugs, or all dietary supplements in general, are unsafe or ineffective.  Research from the latest edition of the Journal Of Strength and Conditioning Research, however, tells a different story.

In the study, which was double-blinded and placebo-controlled to reduce the possibility of bias and maximize accuracy, participants were given a generic thermogenic supplement, containing typical ingredients found industry-wide, such as caffeine, niacin and capsicum extract.  An array of measurements were taken during four phases: 30 minutes of initial rest; 50 minutes of rest after supplementation; 60 minutes of light exercise (treadmill walking); and 50 minutes of recovery after exercise.

Researchers found several significant differences between the thermogenic and placebo groups. Energy expenditure, even at rest, was higher in the thermogenic supplement, with the biggest difference around the 50-minute mark.  During and after exercise, energy expenditure increased by as much as 11% when comparing the thermogenic group to the placebo group.

Another difference was found when the researchers measured oxygen consumption rate and respiratory exchange rate.  With the thermogenic supplement, there were significant increases in oxygen consumption, which in past studies has been linked to an increase in lipolysis - the breaking down of fat for energy.  And while blood pressure and heart rate increased slightly, the changes were not long term or harmful.

As a result, the researchers concluded that the thermogenic aid would be helpful in weight management.  However, they did note that it would be most effective when combined with exercise, and that due to side effects such as anxiety, nausea, dizziness and headaches, users should avoid consuming supplements with large (400-500mg) doses of caffeine.

In addition, the researchers cited prior research to suggest which ingredients might be most effective.  They noted that "caffeine, capsaicin, bioperine and niacin my increase EE [energy expenditure] and improve body composition" (1).

SOURCES:

1. Ryan, D., et al. Acute Effects of a Thermogenic Nutritional Supplement on Energy Expenditure and Cardiovascular Function at Rest, During Low-Intensity Exercise, and Recovery from Exercise. Journal of Strength and Conditioning Research, 2009; 23(3):807-817

One of the common beliefs that many people have with regards to weight training is that the heavier weight you’re attempting to lift, the longer rest periods you should be taking.  This has some people utilizing rest periods of up to five minutes in some cases during their hypertrophy exercises.

Is this long of a rest period really necessary though?  That’s what researchers from the Department of Biology of Physical Activity and Neuromuscular Research Center decided to look at in a study they conducted.

The study’s design was laid out so that the subjects would perform a 6-month period of strength training exercises, which was divided into two separate 3-month training periods.  The first training period consisted of short rest periods of 2 minutes in length between sets while the second training period consisted of 5 minute rest periods between sets.

After the different training sessions, the concentrations on total testosterone (T), free testosterone (FT), cortisol (C), growth hormone (GH) maximum isometric strength of the leg extensors, right leg one repetition maximum, dietary analysis, and muscle cross-sectional area of the quads.

After the training periods were completed, the results revealed that both protocols led to an increase in acute serum T, FT, C, and GH.  In addition to this, both groups performed similarly in terms of gains in both muscle mass and muscle strength.  There were also no significant statistical changes between basal hormone concentrations during the training period.

Therefore, the take-home message we can use from this study is that the length of recovery time between sets after the 2 minute mark isn’t going to have a major noticeable difference on the neuromuscular or hormonal responses in long-term training situations.  

If you were to take the rest periods shorter than 2 minutes you may see greater differences occurring, but past the two minute mark, you may be unnecessarily lengthening your workout sessions.

So, keep this factor in mind if you’re one of those who likes using four or five minute rest periods between sets.  Ask yourself whether you really need this much rest or if you’re just extending the down time for socialization or psychological purposes.

Reference:
Ahtiainen, JP. Et al. (2005).  Short vs. long rest period between the sets in hyertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men. Journal of Strength and Conditioning Research. Aug;19(3):572-82.

Within the research it has been known for some time, that the branch chain amino-acids can reduce delayed onset muscle soreness (DOMS) that follows an intense workout seesion. But what other amino-acids can further assist in reducing DOMS?  Enter one of the now most popular and beneficial amino-acids in sports nutrition today, beta-alanine. Most of us by now are aware of beta-alanine benefits on lean body mass, strength and endurance, but its benefits don’t stop there. A recent study using 8 fit subjects, had them ingest 3.2grams of beta-alanine, spread into smaller doses, with their last dose being ingested with 5 grams of BCAAs. The study went just one week and looked at markers of muscle damage and the pain brought on by DOMS. What this study found was the reduced effect of DOMS that BCAAs can bring about, can be further enhanced by combining them with beta-alanine. So not only is beta-alanine great for building muscle and increasing muscular performance, it also apears now it may decrease DOMS.

Attenuation of eccentric exercise-induced delayed onset muscle soreness (DOMS), muscle damage and oxidative stress by ?-alanine (?A) and branched-chain amino acids (BCAA)
Masaru Furukawa1, Sean Davies2, Kazunori Mawatari3, Anne Kelsen1, Muyao Li1 and Naomi K Fukagawa1
University of Vermont, Burlington, VT Vanderbilt University, Nashville, TN Ajinomoto., Inc, Tokyo, Japan

Posted by: ATHLETIC EDGE NUTRITION

Green tea has been in use for thousands of years, and throughout its history, countless benefits have been attributed to the ancient beverage.  Unfortunately, sufficient scientific evidence has not kept pace with the often miraculous claims.  Just a few of the powerful benefits of Green tea are: increasing metabolism speed, reducing LDL cholesterol and boosting HDL cholesterol production, treating multiple sclerosis, and preventing neurological diseases including Parkinson’s and Alzheimer’s.  According to some, it seems that there is nearly nothing Green tea can’t do.  The bad news is that few of these claims have been backed up with evidence.  The good news?  Recent research has suggested that Green tea does indeed have powerful benefits.

Green tea is commonly touted as a powerful tool for dieters looking to get the extra edge when shedding weight.  A recent study from the University of Birmingham investigated this claim, comparing the effects of green tea ingestion in conjunction with exercise.  Given the results, it’s not surprising that some regard Green tea as miraculous; the study found that average fat oxidation rates - the amount of fat used for energy in the body - were 17% higher in the group that ingested Green tea extract than the placebo group (1).  Enhanced fat oxidation is important for anyone trying to improve their body composition, but it is especially crucial for bodybuilders, as it spares muscle glycogen.

Additionally, the study showed that the ingestion of Green tea extract increased insulin sensitivity by 13% (1).  This improvement has many potential benefits, as low insulin sensitivity - or insulin resitance - is linked with high blood pressure, diabetes, low HDL cholesterol and obesity.

Other research suggested that the benefits of Green tea weren’t just limited to the body though.  The ancient beverage appears to have powerful effects on the mind as well, according to a study investigating the causes of, and potential solutions for, breathing disorder sleep apnea.  This study found that oxygen deprivation, a result of breathing disorder sleep apnea, caused oxidative stress in the brain.  Oxidative stress is very dangerous, as it can damage cell proteins, membranes and genes.  Interestingly, though, when test subjects were supplied with green tea polyphenols (antioxidants), the brain was protected from this stress, and the effects of the oxygen deprivation were kept at bay (2).

So while the supposed benefits of Green tea still outweigh the scientific evidence, there is some proof behind a few of its powers.

SOURCES:

1. Venables, Michelle C, et al.  Green Tea Extract Ingestion, Fat Oxidation, and Glucose Tolerance in Healthy Humans.  American Journal of Clinical Nutrition, 2008; 87(3): 778-784

2. Burckhardt, Isabel C, et al.  Green Tea Catechin Polyphenols Attenuate Behavioral and Oxidative Responses to Intermittent Hypoxia.  American Journal of Respiratory and Critical Care Medicine, 2008; 177: 1135-1141

As everyone gears up for the summer, more and more people are going to be utilizing a low calorie diet.  Some will take this to the very extreme, pushing their total calorie intake as low as they can manage hoping for maximum fat loss.

At the same time, they may start to implement more cardio sessions into their week, sometimes cutting back on resistance training at the same time.  This is one of the biggest mistakes you could make however, so you need to be sure you avoid it.  If you haven’t yet realized weight training’s role in fat loss, it’s time you read up on this and take it seriously.

To illustrate this point, a study that was conducted out of the West Virginia University looked at the impact a resistance training program would have on the body compared with an aerobic training program when all subjects were following a very low calorie diet.

They had twenty subjects consume a diet that consisted of 800 calories and divided these subjects into two different groups.  The first group also performed one hour of cardiovascular activity (walking, biking, or stair climbing) four times a week or else resistance training three days a week, completing 10 different stations for two to four sets of 8 to 15 repetitions for a twelve week period.

At the start of the study the subjects were all of similar body weight, composition, aerobic capacity, and had similar resting metabolic rates.  After the twelve weeks had elapsed, these measures were looked at again to notice differences between the workout program types.

The results indicated that maximum oxygen consumption increased significantly in both groups (by similar amounts), but bodyweight decreased more in the cardio group compared with the resistance training group.  But, the important thing to note is that the cardio group also lost a significant amount of lean body weight, while the resistance training group maintained their body weight.  In addition to this, the resistance training group also showed an increase in resting metabolic rate while the cardio group showed a decline.

Thus from these results we can conclude that resistance training during a very low calorie diet does a far superior job at maximizing the amount of pure fat loss that’s seen, while maintaining lean body weight and keeping metabolic rates higher.

Reference:
Bryner, RW. et al.  (1999). Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. Journal of American College of Nutrition. April;18(2):115-21.