Weight Training: More Sets and More Weight Better for Improving Insulin Sensitivity and Blood Sugar Levels
The early 2000s were the anti-insulin era, in which numerous low-carb hucksters became very, very rich portraying insulin as some kind of evil diabolical hormone waiting to turn us all into diabetic tubs of lard.
Their Bozo-the-Clown approach to biochemistry belied the fact that insulin is absolutely vital to human life. Without insulin, your life expectancy would be shorter than the list of intelligent policies emanating from Julia Gillard. If it wasn’t for insulin, glucose molecules would remain at vastly excessive levels in the bloodstream, running amok like a bunch of free-radical-producing, cross-linking delinquent vandals. Insulin helps restore law and order in the bloodstream, shuttling glucose into muscle and organ cells where it’s used to replenish glycogen and to provide fuel for energy production. Insulin also promotes cellular uptake of amino acids, enhancing growth and repair of your muscles, organs and tissues. The more sensitive your cells are to insulin, the more efficiently it will accomplish these tasks.
The trouble with insulin begins when your body produces too much or not enough of it. By improving your insulin sensitivity, you reduce the amount of insulin required for optimal growth signalling and transport of glucose and amino acids. In turn, over a longer time frame this will greatly decrease the risk of pancreatic exhaustion and impaired insulin output that leads to diabetes.
Basically, having heightened insulin sensitivity is a beautiful thing. Being insulin resistant, on the other hand, just plain sucks.
In rodent studies, improved insulin sensitivity appears to be a major reason for the extended lifespan in critters undergoing calorie restriction. Emerging research suggests greater insulin sensitivity may also be a primary force behind the extended lifespans of people who live in to their 90s and beyond[2-4].
Which means you may not need to eat like a sparrow to enjoy the benefits of long term calorie restriction, great news for those of us who need plenty of calories to remain highly active, not to mention those of us who consider eating to be one of life’s greatest pleasures, right up there with sex, skydiving, and scoring cheap S-Works shoes on ebay. And you may not need to endure the potential pitfalls of lifelong calorie restriction such as reduced bone and muscle mass, great news for those of us with an aversion to owning frail limbs, miniscule muscles and plastic hips. Instead, there are numerous other methods for increasing insulin sensitivity; my two favourites are iron reduction, and exercise.
I’ll discuss the hugely important topic of iron reduction another time; today, we’ll look at the impact of exercise volume and intensity on insulin sensitivity.
Researchers from Arizona State University recently examined the effects of resistance exercise volume and intensity. Seventeen participants with impaired fasting glucose (100–125 mg/dL) completed 4 separate bouts of resistance exercise under moderate intensity (65% 1 repetition maximum [1RM]) or high intensity (85% 1RM) conditions within the confines of single set and multiple set (4 sets per exercise) protocols (in contrast to popular gym vernacular, in weightlifting and research circles the term “intensity” refers to the percentage of 1RM you are lifting, not how loudly you grunt, scream, fart and carry on in the weight room).
Fasting blood samples were taken at baseline and 24 hours post-exercise for each exercise condition to measure fasting plasma glucose and fasting serum insulin to calculate insulin sensitivity.
The resistance exercise protocol design comprised multi-joint exercises, including squats, leg press, lunges, step-ups, bench press, lat pulldowns, shoulder press, and upright rows. Moderate-intensity protocols were determined at 65% of participants estimated 1 repetition maximum. At this intensity, participants performed 12 to 15 repetitions for all 8 exercises. The high-intensity protocol was set at 85% of the estimated 1 repetition maximum, requiring participants to complete 6 to 8 repetitions of each exercise. Volume was determined by number of sets performed for each exercise. Single and multiple set designs were paired with moderate and high intensity to create the 4 protocols.
When the results were in, all the protocols produced reductions in fasting blood glucose and improved insulin sensitivity at 24 hours post-workout. However, both multiple set protocols resulted in greater reductions in blood glucose, while the high-intensity/multiple set protocol produced far greater improvements in insulin sensitivity.
Sometimes more is better. When it comes to weight training, more sets and more weight equals greater improvements in glycemic control. Even better improvements can be expected when you add endurance exercise into the mix (not to mention greater gains in life expectancy, see below).
Do Elite Athletes Live Longer than the General Population?
We all know that exercise is good for us, but what about elite level athletic training? What kind of effect does that have on longevity? Does it extend life, or do hard-training professional athletes wear themselves out and keel over prematurely?
Researchers from the University of Nevada, Las Vegas, wondered about this too, so they reviewed the literature examining longevity and mortality in elite athletes. They found fourteen studies comparing longevity and mortality in elite athletes with that of the general population. Included in these studies were data for endurance athletes, power athletes and mixed-sport athletes.
Their analysis showed that long-distance runners and cross-country skiers lived significantly longer than the general population (2.8–5.7 years longer). The observed deaths among endurance athletes were less than two-thirds of the expected deaths estimated from the general population. Lower numbers of deaths from cardiovascular disease contributed to the better survival rates of these athletes.
Soccer, ice-hockey and basketball players, track and field jumpers, short-and middle-distance runners, and hurdlers also survived longer than the general population (4.0 years longer).
In contrast to the better survival rates observed among endurance and mixed-sports athletes, mortality and longevity of power athletes reported across the studies were not consistent. Professional American football players were shown to live an average of 6.1 years longer than controls from the general public, whereas New Zealand rugby players had the same life expectancy as the general population. The New Zealand researchers hypothesised that the rugby players did not live longer than expected, because they did not maintain high fitness levels after retirement and/or playing rugby itself deteriorated their health. Finish researchers reported similar mortality and longevity between power athletes (weightlifters, wrestlers, boxers, track and field throwers) and reference cohorts (life expectancy = 1.6 yearslonger). Another study showed 12.9% of Finnish powerlifters died prematurely compared to 3.1% of the age-matched general population during a 12-year follow-up (4.6-fold higher risk of death).
The study concluded that Danish elite athletes survived longer than the general population under the age of 50 years, whereas there were no significant differences in survival rates between the groups after 50 years old. Whether this was due to the diminishing impact of exercise during post-retirement inactivity is unclear (other researchers found that athletes were generally more likely to maintain higher levels of post-retirement activity than non-athletes).
These results indicate that overall, elite athletes live longer than the general population, but this greater longevity is largely confined to athletes whose sports require a high level of cardiovascular conditioning. All you cardio-phobic bodybuilders and strength athletes who avoid skipping, riding and running because “it’s catabolic, man!”, take note. When it comes to longevity, a well-conditioned heart will increase your odds far more favourably than a well-trained bicep.
Anthony Colpo is an independent researcher, physical conditioning specialist, and author of the groundbreaking books The Fat Loss Bible and The Great Cholesterol Con. For more information, visit TheFatLossBible.net or TheGreatCholesterolCon.com
Copyright © Anthony Colpo.
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