Showing posts with label which. Show all posts
Showing posts with label which. Show all posts
Sunday, March 8, 2015
Daily injection which is better than dieting or exercise on NHS soon
A treatment of injections that can help people lose a stone more than they normally would by dieting or exercising more has been approved by health watchdogs.
Liraglutide, which has been described by doctors as life-changing, could be available on prescription in months.
Slimmers typically lose almost a stone more than they would by simply watching how many calories they consume and doing more exercise.
Trials showed that some severely obese patients lost so much weight they were able to abandon their wheelchairs and walk normally for the first time in years.
Liraglutide also lowers blood pressure, raises good cholesterol and prevents diabetes.
According to its makers, Novo Nordisk of Denmark, the drug even produces a feel-good factor, making dieting a pleasure.
But some experts have already warned it does not provide a long-term solution to the growing problem of obesity in Britain.
Novo Nordisk will apply for it to be prescribed on the NHS after Friday’s ruling by the European drugs regulator that it is safe and effective.
There are fears however that Nice – Britain’s drugs rationing body – will judge it too expensive for routine use on the NHS.
Liraglutide costs from £2.25 a day, which is roughly double the price of Orlistat, the only other prescription diet drug.
Patients inject the drug into their stomach before breakfast every day. It works by suppressing appetite.
Liraglutide, which will be given the brand name Saxenda, is already used at a lower dose to treat diabetes. It is based on a hormone found in the gut and sends signals to the brain that trick it into feeling full.
As a result, people eat 10 per cent less food than normal.
Trials of Liraglutide found that men and women who injected themselves daily lost an average of 19lb in 12 months. This is almost a stone more than they would lose by being on a diet and increasing the amount they exercise.
Furthermore one third or those who took part in the trials shed 23lb – more than a stone and a half. For a 14 stone woman that kind of weight loss would usually mean dropping two dress sizes.
The drug which, like insulin, comes in an injectable pen, also has such a significant effect on blood pressure that patients can dispense with the drugs they use to keep it under control.
Like Orlistat, its prescription is likely to be limited to those who are obese or who are overweight and have another health problem such as high blood pressure.
Mike Lean, professor of human nutrition at Glasgow University, told the Mail: "Liraglutide is absolutely life-changing for many of our most difficult-to-manage patients. Most do well, and some amazingly well. And it is extraordinarily safe, at least over the two to three years for which we have good evidence, with no signals to suggest serious side-effects.
"The only real downside is that it is jolly expensive."
Professor Jason Halford, former president of the UK Association for the Study of Obesity, said: "It is potentially very exciting. The real benefit of it is that it is targeting appetite. It strengthens the effects of satiety."
Obesity levels have doubled over the past two decades, making the UK the second-fattest nation in Europe.
Exptensive research has found that being obese can lessen persons lifespan by as much as nine years and raise the risk of a host of health problems including diabetes, heart disease, stroke and cancer.
Tests have shown that dieters taking liraglutide lose almost twice as much weight as those on Orlistat.
However, Professor Iain Broom, director of the Centre for Obesity Research at Robert Gordon University in Aberdeen, said that drugs were never going to provide a long term answer to obesity.
He said: "Until society changes and the Government’s relationship with the food industry changes and the food industry itself changes, we are not going to get anywhere very fast."
The European Commission is expected to approve the drug’s licence within the next two months, paving the way for it to go on sale. Novo Nordisk says it could be launched in Europe, including the UK, this year.
By Patrick Sawer
Source: http://www.telegraph.co.uk/lifestyle/wellbeing/dietandfitness/11367203/Daily-injection-which-is-better-than-dieting-or-exercise-on-NHS-soon.html
Saturday, March 7, 2015
Carbohydrate Supplementation During Workouts Who Benefits How Much and Which Type s of CHO are Best
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| Compared to liquid beverages, gels have the advantage of causing lower GI stress, when significant quantities of CHOs are consumed during exercise. Bars, can be held in the cheek pouch and chewed during critical phases of a race. |
As a seasoned student of the SuppVersity you will know that certain paradox involved with regard to the duration / type of exercise. Short exercise durations, for example, shouldnt require large CHO boluses, long duration exercise, on the other hand, is fueled mostly by fat - so why should you supplement with carbohydrates, anyway?
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That being said, the human physiology dictates that the use of carbohydrate supplements during aerobic workouts that last less than 60 minutes is useless, because muscle glycogen is generally not limiting to performance when exercise durations are less than ~60 minutes.
It should not work for short duration exercise, but it still does
Interestingly, 16 out of 23 studies, Trent Stellingwerff and Gregory R. Cox from the Canadian Sport Institute-Pacific and the Australian Institute of Sport reviewed for their recent paper in Applied Physiology have found that carbohydrate supplementation and/or oral (mouth) exposure to carbohydrate can improve performance of tasks less than 1 hour in duration:
This effect of CHO mouth-washing to improve performance in events from 30-60min has now been replicated in several other performance studies (10 of 13 studies) using both cycling and running interventions and with both sweet (sucrose) and non-sweet (maltodextrin) caloric CHO sources,as compared to 5 non-caloric artificial sweetener placebo trials showing no performance enhancing effects."In 2004 a seminal paper was published showing that a carbohydrate mouth-wash (swirling 25ml of a 6% CHO beverage (only ~1.5g of CHO in 25ml [6.4% maltodextrin solution (CHO)]) around in the mouth for ~10 sec, every 7.5min) significantly improved time trial (TT) performance [in seven male and two female endurance cyclists] by ~3% (Carter et al. 2004a)." (Stellingwerff & Cox. 2014)
You wont fully deplete your muscular glyocogen levels
during short duration resistance training (Haff. 2003)
Studies evaluating the effects on perceived exertion (Fares et al. 2011) found similar benefits all of which support the idea that the effect does not occur in the musculature, but rather in the head."All these findings have been mechanistically supported with a functional magnetic resonance brain imaging study showing that CHO mouth-washing from both sweet tasting glucose and non-sweet maltodextrin can stimulate the brain areas of the insula/frontal operculum, orbitofrontal cortex and striatum, which are involved with brain centers responsible for reward and motor control (Chambers et al. 2009). Interestingly, if the mouth (oral receptors) and GI tract is by-passed by CHO infusion straight into the blood stream then 1h cycling TT performance was unaltered as compared to no CHO supplementation (Carter et al. 2004b)." (Stellingwerff & Cox. 2014)
Figure 1: Hard to believe, but true - In 2010 Pottier et al. observed that CHO mouth-rinsing, but not CHO ingestion increases the 1h high intensity time-trial performance in trained subjects.
So what do you do to benefit during short-duration (<60) minute workouts? To benefit during short duration exercise exercise (<1h) ~1.5g of high GI carbohydrates (30g/h total = max) consumed or used as a mouth-wash in servings of 25ml for 5 to 10 sec every 8 to 10 min of exercise will do the trick. Since it can be difficult to actually drink / mouth-wash with CHO during critical phases of the race, Stellingwerff and Cox suggest "placing a sports confectionary in the cheek cavity" as a more practical option for some athletes.
It should be obvious that the physiological, or rater intra-muscular benefits of carbohydrate supplements increases with the exercise duration.CHO supplementation during exercise that lasts 60 minutes or longer
In view of the fact that it is 100% logical and well established by studies by Coyle et al. (Coyle 1992a; Coyle 1992b) that the intake of carbohydrate (glucose alone, and glucose + fructose blends) can significantly improve prolonged endurance capacity and performance (>60min of exercise (Jeukendrup 2010)).
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| Figure 2: Overview of the performance increases in the 50 studies Stellingwerff & Cox reviewed (2014) |
Glucose + fructose - the combination advantage
As a SuppVersity reader youve previously heard about the benefits of combining glucose and fructose in your intra-workout beverage. It is thus only logical that most commercially available formulas are mixtures glucose + fructose (GLU:FRU) or maltodextrin + fructose - so-called "multi-transportable CHOs". The advantage of using both glucose and fructose is that the carbohydrates will be absorbed via SGLT1 and GLUT5 intestinal transporters.
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| Comparison of single vs. mutliple CHO sources (CHO, carbohydrate; FRU, fruc- tose; GLU, glucose; Perf, performance; P, placebo; TT, time-trial; TTE, time to exhaustion; Signif, Significant; SUC, sucrose; Stellingwerff & Cox. 2014) |
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| Specifically during long(er) duration exercise, when the carbohydrate consumption can exceed 60g/h there is a significant performance increase with multi- vs. single source carbohydrate supplements (Stellingwerff & Cox. 2014) |
Now an increase in carbohydrate oxidation alone does not sound like something you would aim for as an endurance athlete. In practice, increases in carbohydrate oxidation have yet been shown to increase the performance during prolonged exercise bouts compared to isocaloric glucose-only beverages. (Currell et al. 2008; Triplett et al. 2010; OBrien et al. 2011; OBrien et al. 2013).
So how much does it take during long(er) 1-2h+ exercise: Youve already learned that glucose + fructose mixtures should be preferred to carbohydrate supplements with only one type of CHO. While 30-60g/h, which is the amount of carbohydrates that is currently suggested by the American College of Sport Medicine (ACSM 2000; Sawka, Burke et al. 2007) appears to be be enough for exercise durations ranging from 60-120 minutes, recent evidence suggests that hard exercise bouts which last longer than 2h require up tp 90g/h or carbohydrate solutions with a CHO content of >8%.
Needless to say that there is still research to be done with respect to individual influencing variables of carbohydrate requirements. The currently available evidence, for example, is largely based on results from runners and cyclists. Two other factors / issues that come to mind are...- the dose-response relationship, which appears to be capped at 75g/h - at least according to a large-scale multi-center study by Smith et al. (Smith. 2013) who found that their subjects, endurance trained cyclists or triathletes experienced significant performance increases, with increasing amounts of carbohydrates (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120g of CHO/h) during a 2h constant load ride.
The CHO given was a 1:1:1 glucose:maltodextrin:fructose blend. Results indicated incremental performance improvements of 1.0%, 2.0%, 3.0%, 4.0%, and 4.7% at 9, 19, 31, 48, and 78g CHO/h, respectively, with diminishing performance enhancement seen at CHO levels >78g/h.
Figure 3: Mean log time to complete time trial (natural) as function of CHO treatment condition with fitted quadratic curve (with 95% CI of mean curves). Differences 100 represent percent change in performance. The quadratic function relating CHO ingestion rate to time complete time trial for 43% (95% CI = 11%–75%,P= 0.059) of the variation in mean performance score (Smith. 2013)
The optimal amount for performance (+4.7%) was 78g/h, with a range of 68 to 88g/h. However, even at 10g/h, a 1.0% increase in performance was observed, showing even a small amount of carbohydrate has the potential to positively impact performance. - the optimal mix of glucose, dextrose, fructose, maltodextrin or other "special" carbohydrates - needless to say that waxy maize, hydroxypropyl distarches (learn more) or the expensive fast absorbing highly insulinogenic patented carbohydrate source Vitargo come to mind, when we are talking about finding the optimal mix of different carbohydrate sources - a mix, by the way, of which you can safely assume that it will differ according to the physiological demands of the workout and the exercise duration.
One thing we shouldnt forget, though, is that next to optimal performance, optimal GI tolerance, i.e. the absence of bloating, diarrhea & co would be an important criteria the "optimal" carbohydrate blend would have to meet.
the impact of carbohydrate supplementation on hormonal changes during and in response exercise - several human studies suggest that CHO supplementation attenuates the suppression of the hypothalamic-pituitary-gonadal axis and the rise in stress hormones during periods of intense training; a recent rodent study shows that the provision of carbohydrate supple- ments can prevent / reverse exercise-associated menstrual dysfunction (de Sousa. 2010; Zhao. 2014)
Figure 4: CHO suppl. ameliorates testosterone reductions in 800m runners (de Sousa. 2010)
Bottom line: As of now it looks as if the recommendations I made in the light(er) blue boxes for short (<1h), long (1-2h) and ultra-long (>2g) workouts are the best we have.
What I find particularly interesting is that for shorter duration exercise situations (<1h) and high(er) exercise intensity, similar benefits can be achieved with swallowing vs. outh-washing with only 30g/h of liquid CHO sources. Performance increases in the 2.6% ± 3.3% range may not sound earth-shattering, but if you were running for an hour, your competitor who made sure to bring a carb bottle would be 83s faster than you are - thats 83s which could make the difference between first and last place.
For longer duration exercise, the studies, Stellingwerff and Cox reviewed in the previously cited article yielded an intermediate improvement of 4.9%±4.9% with significantly higher values in studies investigation long(er) + higher intensity exercise. The notion that carbohydrate supplements were useless and the various position statements of sporting bodies all over the world just a concession to the sponsoring money of the industry is thus unwarranted | Comment on Facebook!
References: |
| For the majority of resistance trainees, intra-workout carbohydrate supplementation is at best facilitative. The repletion of the depleted glycogen stores after your workouts, however, is necessary | learn more about glycogen repletion |
For longer duration exercise, the studies, Stellingwerff and Cox reviewed in the previously cited article yielded an intermediate improvement of 4.9%±4.9% with significantly higher values in studies investigation long(er) + higher intensity exercise. The notion that carbohydrate supplements were useless and the various position statements of sporting bodies all over the world just a concession to the sponsoring money of the industry is thus unwarranted | Comment on Facebook!
- Carter, J., Jeukendrup, A.E., Mundel, T., and Jones, D.A. (2003). Carbohydrate supplementation improves moderate and high-intensity exercise in the heat. Pflügers Archiv : European journal of physiology446: 211-9.
- Carter, J.M., Jeukendrup, A.E., and Jones, D.A. (2004a). The effect of carbohydrate mouth rinse on 1-h cycle time trial performance. Medicine and science in sports and exercise36: 2107-11.
- Carter, J.M., Jeukendrup, A.E., Mann, C.H., and Jones, D.A. (2004b). The effect of glucose infusion on glucose kinetics during a 1-h time trial. Medicine and science in sports and exercise36: 1543-50.
- Chambers, E.S., Bridge, M.W., and Jones, D.A. (2009). Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity. The Journal of physiology587: 1779-94.
- de Sousa, Maysa Vieira, et al. (2010). Effects of carbohydrate supplementation on competitive runners undergoing overload training followed by a session of intermittent exercise." European journal of applied physiology 109.3: 507-516.
- Fares, E.J. and Kayser, B. (2011). Carbohydrate mouthrinse effects on exercise capacity in pre- and postprandial States. J Nutr Metab2011: 385962.
- Pottier, Andries, et al. (2010). Mouth rinse but not ingestion of a carbohydrate solution improves 1‐h cycle time trial performance" Scandinavian journal of medicine & science in sports 20.1: 105-111.
- Sawka, M.N., Burke, L.M., Eichner, E.R., Maughan, R.J., Montain, S.J., and Stachenfeld, N.S. (2007). American College of Sports Medicine position stand. Exerciseand fluid replacement. Medicine and science in sports and exercise39: 377-90.
- Smith, JohnEric W., et al. (2013). Curvilinear dose-response relationship of carbohydrate (0-120 g/h) and performance." Med Sci Sports Exerc 45.2: 336-341.
- Stellingwerff, T., & Cox, G. R. (2014). Systematic Review: Carbohydrate Supplementation on Exercise Performance or Capacity of Varying Durations. Applied Physiology, Nutrition, and Metabolism (2014). Ahead of Print.
- Zhao, Can, et al. (2014). Effects of carbohydrate supplements on exercise-induced menstrual dysfunction and ovarian subcellular structural changes in rats." Journal of Sport and Health Science 3.3: 189-195.
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