Weightlifting 'reduces men's diabetes risk'

"Pumping weights five times a week can reduce the risk of type 2 diabetes by a third," The Daily Telegraph has reported.

The news is based on the results of a large US study which found that men who performed weight training reduced their risk of developing type 2 diabetes.

Previous research has shown that regular moderate or vigorous physical activity for at least 30 minutes a day reduces risk of type 2 diabetes. The authors of the study also reported that other studies have shown that resistance training can improve blood sugar control in people with diabetes. This is the first significant piece of research that has also found a link between weight training and a reduced risk of actually developing diabetes.

This study found that at least 150 minutes of weight training a week reduced the risk of developing type 2 diabetes by just over one third (34%). Performing at least 150 minutes of aerobic exercise a week (such as brisk walking, jogging, running, cycling, swimming, tennis, squash and rowing) reduced risk to a slightly greater extent (52%). The greatest risk reduction was observed when performing a combination of both weight training and aerobic exercise (59%).

Regular exercise, in addition to other healthy lifestyle behaviours, is the best way to reduce the risk of many chronic diseases, including type 2 diabetes. This study supports general health advice, finding that weight training or aerobic exercise reduced the risk of type 2 diabetes in professional men. Weightlifting may be a useful exercise addition, or alternative, for people who have difficulty in performing aerobic exercise, but as with all forms of exercise it is advisable to exercise within your own limits. The key advice is to take regular exercise – weightlifting may not be the best workout for everyone.

Where did the story come from?

The study was carried out by researchers from Harvard School of Public Health, Harvard Medical School, Brigham and Women’s Hospital, the University of Southern Denmark and the Norwegian School of Sport Sciences. It was funded by the US National Institutes of Health. The study was published in the peer-reviewed journal, Archives of Internal Medicine.

This story was reported in The Daily Telegraph and the Daily Mail. The Mail’s headline made it clear that the study had only been performed in men.

The coverage of the report in both papers was accurate.

What kind of research was this?

This was an analysis of data collected from a prospective cohort study of professional men in the US: the Health Professionals Follow-up Study (HPFS). This particular analysis aimed to determine whether there was a link between weight training and the risk of type 2 diabetes. This is the ideal study design to answer this question. However, cohort studies cannot show that weight training is the cause of any change in risk of type 2 diabetes, as researchers cannot exclude the possibility that other factors (called confounders) are responsible for any link seen.

In particular, as the HPFS was not set up to specifically to answer this study question, it is possible that other relevant factors may not have been considered.

What did the research involve?

This study used the HPFS, an ongoing cohort study, which followed up male health professionals aged between 40 and 75 in 1986. Information on weightlifting and other forms of exercise had been reported from 1990 onwards. Therefore, for the purpose of this particular study, the researchers excluded men who in 1990 had diabetes, cancer, angina or past heart attack, coronary artery bypass graft, other heart conditions, stroke or pulmonary embolism.

This left 32,002 men who, between 1990 and 2008, completed a questionnaire every two years on diseases and personal and lifestyle characteristics, such as height, weight, smoking status, diet and physical activity. Weekly time spent on weight training and aerobic exercise (including jogging, bicycling, swimming, tennis and calisthenics) were obtained.

The development of type 2 diabetes was also assessed on the questionnaires, and men who reported a diagnosis of type 2 diabetes were asked to complete supplementary questionnaires so that the diagnosis could be confirmed. The diagnosis of diabetes was confirmed by medical record review in a subgroup of participants (97% of the participants had their diabetes confirmed). Deaths were also monitored.

The researchers looked to see if there was an association between weight training or aerobic exercise and the development of type 2 diabetes. When looking to see if there was a link, they tried to adjust for other factors that may explain the association, including:

• age
• smoking
• alcohol consumption
• coffee intake
• ethnicity
• family history of diabetes
• diet (including total intake of energy, trans-fat, polyunsaturated fat to saturated fat ratio, cereal fibre, whole grain and glycaemic load)

What were the basic results?

The researchers found that there were 2,278 new cases of type 2 diabetes follow-up, and that:

• More time spent on weight training or on aerobic exercise was associated with decreased risk of type 2 diabetes (a dose-response relationship).
• Performing weight training only for at least 150 minutes a week was associated with a statistically significant 34% reduced risk of type 2 diabetes, compared with doing no weight training (after adjusting for aerobic exercise, other physical activity of at least moderate intensity and television viewing). 
• Performing aerobic exercise for at least 150 minutes a week was associated with a statistically significant 52% lower risk of type 2 diabetes, compared with doing no aerobic exercise (after adjusting for weight training, other physical activity of at least moderate intensity and television viewing).
• Men who did both aerobic exercise and weight training for at least 150 minutes a week had a 59% reduction in risk of type 2 diabetes, which was the greatest reduction in risk (when compared with doing no aerobic exercise or physical activity).

How did the researchers interpret the results?

The researchers concluded that weight training was associated with a significantly lower risk of type 2 diabetes, and that this association is independent of aerobic exercise. They concluded that their results support that “weight training serves as an important alternative for individuals who have difficulty adhering to aerobic exercise, but the combination of weight training with aerobic exercise confers an even greater benefit”.

Conclusion

This cohort study found that weight training is associated with a reduced risk of type 2 diabetes, with increased training associated with reduced risk in male health professionals. This association was independent of aerobic exercise. However, although the study has focused on weightlifting, performing aerobic exercise was actually associated with greater risk reduction than weightlifting. The greatest reduction in risk was seen in men who performed both weight training and aerobic exercise for 150 minutes a week.

This study has both strengths and weaknesses. The strengths include the large number of participants, the long follow-up and the fact that both physical activity and other factors that may explain the association (such as diet and alcohol consumption) were assessed regularly. However, the data was collected by self-reported questionnaires, which may be subject to reporting bias. The researchers also did not collect data on the type or intensity of the weight training.

Only male health professionals aged between 40 and 75 years old at baseline were included, and most of the men were white. This means that the findings may not apply to women, younger men or other ethnic groups.

The latter factor may be particularly important as rates of type 2 diabetes can vary significantly between ethnic groups. For example, the condition is more common in those of South Asian, African-Caribbean or Middle Eastern descent.

Finally, the researchers cannot exclude the possibility that the association seen may be explained by another factor that they have not controlled for. The fact that the Health Professionals Follow-up Study was not set up specifically to study whether weightlifting influences risk of diabetes may further increase the possibility that other relevant factors have not been taken into account.

In conclusion, this study supports general health advice by finding that weight training or aerobic exercise reduces the risk of type 2 diabetes in professional men. Weight training may be a useful exercise addition, or alternative, for people who have difficulties in performing aerobic exercise.

However, further studies are required to confirm the association between weight training and diabetes, to see whether it also applies to women and to examine whether the duration, type and intensity of weight training make any difference.

Two-and-a-half hours of weight training a week is a big commitment and shouldn’t detract from other forms of exercise. It is also important to be aware that, as with all forms of exercise, it is advisable to exercise within your own limits. The key advice is to take regular exercise – weightlifting may not be the best workout for everyone.

Orignal source: http://www.nhs.uk/news/2012/08august/Pages/Pump-iron-not-insulin-diabetes-weightlifting-risk-reduction.aspx

5 Muscle Building Mistakes (And How to Make Gains)

1) You Always Train in the Same Rep Range

The claim that muscle growth is maximized in a moderate rep range (6-12 reps per set) continues to be a source of debate in the fitness field. Although this theory is backed by some research, evidence on the topic remains far from conclusive. But for arguments sake let’s say that moderate reps are in fact best for gaining size. Does that mean that you should train exclusively in this narrow rep range? The answer is an unqualified, “No!”

Training in a lower rep range (1-5 per set) maximizes strength increases, thereby facilitating your ability to use heavier weights during moderate rep training. In this way, you create greater tension in the muscles, spurring better growth. High reps (15-20 per set), on the other hand, help to increase your lactate threshold. By delaying the buildup of lactic acid, you stave off fatigue when training in the “hypertrophy range,” (the muscle building range) thus increasing time under tension—another important aspect of the growth process. Bottom line is that optimum muscle development is best achieved by using the full spectrum of rep ranges.

Your fix: Periodize your program so that it is built around a moderate repetition protocol, but you make sure to include training in both the lower and higher rep ranges. Although a number of different periodization models work, I recommend a modified linear approach beginning with a strength phase (lower reps), followed by a fairly short metabolic phase (high reps) and then culminating with a hypertrophy phase (the typical 6 to 12 range). When properly implemented, this produces a “supercompensation effect” so that you maximize muscular gains and see a peak at the end of the training cycle.

2) You Use the Same Exercises Every Day

Most people have a limited number of favorite exercises that are staples in their routine. That’s human nature. While it’s okay to have your old stand-bys, they shouldn’t be performed at the exclusion of other movements. Changing up your exercise selection has a couple of important benefits from a mass-building standpoint. For one, it helps to prevent the so-called “repeated-bout effect” whereby muscles become accustomed to the continual use of the same movements, making them increasingly resistant to trauma. Staving off such accommodation allows for greater structural perturbations to muscle fibers. That might sound like a bunch of confusing science to some of you, but what it all means is that changing exercises can facilitate increased growth.

What’s more, muscle fibers don’t necessarily span the entire length of a fiber and are often innervated by different nerve branches. Thus, exercise variety alters recruitment patterns in the musculature, ensuring optimal stimulation of all fibers. Think of it this way: Some people like blonds, other prefers brunettes, and you have those that love redheads. Your muscles are greedy and like them all. So in order to keep them happy, you must give them what they want. That’s why exercise variety provides your muscles with the variety it literally needs for optimal growth. Even slight variations in the exercises you employ will work the muscles somewhat differently, enhancing results.

Your fix: Employ a diverse selection of exercises over the course of your training cycle. This can be accomplished by switching around modalities, training angles, planes of movement, and even your hand and foot spacing. (For instance, on dumbbell curls, think about holding the handle with your pinky against one end of the bell, and on the next set perform with your thumb against the bell. That slight shift will work your biceps in different ways.) The possibilities are almost endless if you think outside the box. There is no hard rule as to how frequently exercises should be changed, but a general guideline is to do so at least on a monthly basis.

3) You Over- or Under-Isolate Your Muscles

When it comes to exercise selection, there are two basic camps. On one end of the spectrum are those who preach that the only way to get big is by performing the “big lifts” such as squats, presses, and rows. On the other end of the spectrum are those who claim that key to muscle-building is “isolating” muscles with flys, curls, extensions, and the like. Who’s right?

Both camps!

Realize that this isn’t an either-or debate; the two types of movements are in fact complementary. Multi-joint exercises involve large amounts of muscle and therefore are highly efficient for packing on mass. Alternatively, single-joint exercises allow for greater targeting of individual muscles (or even portions of muscles), enhancing overall growth and symmetry. Integrating a mix of both types of movements into your routine can have a synergistic effect that improves both muscle size and symmetry.

Your fix: Structure your routine so that it is comprised of a combination of multi- and single-joint exercises. As a general rule, every workout should contain at least one or two “big lifts” and a single-joint move. Oh, and realize that for all practical purposes you can’t “isolate” muscles. The body is designed so that multiple muscles will always be active during exercise performance. Thus, you can only target a given muscle so that it is more active in a given movement.

4) You Always Follow the Straight and Narrow (Sets)

Typical resistance training routines involve performing “straight” sets where you do a set, rest, perform another set of the same exercise, rest, and then continue in this fashion throughout each exercise in your workout. There’s nothing “wrong” with the basic approach; straight sets can and perhaps even should form the foundation of your routine. But it’s also good to mix things up a bit with some specialized techniques. Supersets (performing one exercise followed immediate by another exercise without rest), drop sets (performing a set to muscular failure with a given load and then immediately reducing the load and continuing to train until subsequent failure) and heavy negatives (performing eccentric actions—the lowering of a weight—at a weight greater than concentric 1-repetition maximum) can be excellent additions to a mass-building routine. They help to induce greater metabolic stress and structural perturbations that can take your muscle growth to new heights. These strategies are particularly effective for advanced lifters who need to “shock” their body to spur greater growth.

Your fix: Selectively add specialized techniques such as supersets, drop sets, and heavy negatives into your routine. A word of caution: these techniques should be considered advanced training strategies. Their fatiguing nature increases the risk for overtraining, and it is therefore wise to limit their use to no more than a few microcycles over the course of a periodized program.

5) You Do Too Much Cardio

A goal of many lifters is to increase muscle development while simultaneously reducing body fat levels. In an attempt to accelerate fat loss, cardio is frequently ramped up while performing intense resistance training. Adding some aerobic training a muscle-building routine isn’t necessarily a bad thing. Overdoing it, however, certainly is. You see, the signaling pathways for resistance training and aerobic training are contradictory. Some researchers have coined the term “AMPK-PKB switch” whereby aerobic training promotes catabolic processes (AMPK is involved in pathways associated with protein breakdown, which for your sake can be considered “muscle wasting”) and resistance training promotes anabolic processes (PKB is involved in pathways associated with protein synthesis, or for you, “muscle gaining”). While the concept of a “switch” is a bit overly simplistic (most of the evidence points to anabolism and catabolism taking place along a continuum), there is little doubt that concurrent training has the potential to interfere with anabolism and thereby undermine your ability to build muscle. What’s more, adding extensive cardio to an already demanding resistance-training program can hasten the onset of overtraining, which brings muscle growth to crashing halt.

Your fix: If your goal is to maximize muscle, keep cardio at moderate levels. How much is too much? It ultimately depends on the individual, as some can tolerate more than others. A general guideline is to limit steady state cardio to no more than about 3 or 4 weekly bouts lasting 30 to 40 minutes. Alternatively, 2 to 3 high-intensity interval training workouts a week should be fine for most lifters. Just make sure that you stay in tune with your body and be aware of any signs of overtraining. You also should be aware that unless you’re a newbie to lifting with a fair amount of weight to lose, it becomes increasingly difficult trying to simultaneously gain lean mass while losing body fat. Once you’ve been training for a number of years, it’s best to focus on one goal or the other.

Reference: http://www.bornfitness.com/muscle-building-mistakes/