Tag Archives: exercise

Exercise Reduces Risk of Prostate Cancer

…according to an article in MedPageToday. For unknown reasons, diabetics are less likely than average to get prostate cancer, but they still do.

In a prospective study, white men suspected of prostate cancer and scheduled for biopsy were less likely to have the disease if they were at least moderately active, according to Lionel Bañez, MD, of the Durham Veterans Affairs Medical Center in Durham N.C., and colleagues.

If they did have cancer, they were significantly less likely to have high-grade disease if they had been working out regularly, Bañez and colleagues reported online in Cancer.

Another way to reduce your risk of prostate cancer is to follow the Mediterranean diet.  Other cancers reduced by the Mediterranean diet are breast, colorectal, and uterus.

Steve Parker, M.D.

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Kelly Schmidt, RD, Interviews Eric Pelletier (T1 Diabetes) On Diet and Exercise

Eric is a Crossfitter who owns a Crossfit gym (or box, as they say). Kelly asks him about low-carb eating (even ketogenic) and how to manage food and insulin in the setting of vigorous exercise.  Well worth a read, especially if you have type 1 diabetes.

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“Interval Walking” May Be Healthier Than Regular Walking For Diabetics

Not ready for this? Consider interval walking then.

Not ready for this? Consider interval walking then.

Compared to a regular continuous walking program, interval walking is superior for improving physical fitness, blood sugar control, and body composition (body mass and fatness), according to new research reported in Diabetes Care.

Study participants were type 2 diabetics. Training groups were prescribed five sessions per week (60 min/session) and were monitored with an accelerometer and a heart-rate monitor. Continuous walkers performed all training at moderate intensity, whereas interval walkers alternated 3-min repetitions at low and high intensity. Before and after the 4-month intervention, the following variables were measured: body composition, VO2max, and glycemic control (fasting glucose, hemoglobin A1C, oral glucose tolerance test, and continuous glucose monitoring).

I haven’t read the full report yet, but expect that the interval walkers walked as fast as they could for three minutes (4 mph?) then slowed down to a comfortable stroll (1–2 mph?) for three minutes, alternating thusly for 60 minutes.

This should easily do-able for nearly all type 2 diabetics.  The reported results are consistent with other studies of more vigorous and intimidating interval training.  The only caveat is that it was a small pilot study that may or may not be reproducible.

Steve Parker, M.D.

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What’s Metabolic Syndrome?

metabolic syndrome, low-carb diet, diabetes, prediabetes

He’s at high risk for metabolic syndrome

“Metabolic syndrome” may be a new term for you. It’s a constellation of clinical factors that are associated with increased future risk of type 2 diabetes and atherosclerotic complications such as heart attack and stroke. One in six Americans has metabolic syndrome. Diagnosis requires at least three of the following five conditions:

  • high blood pressure (130/85 or higher, or using a high blood pressure medication)
  • low HDL cholesterol:  under 40 mg/dl (1.03 mmol/l) in a man, under 50 mg/dl (1.28 mmol/l) in a women (or either sex taking a cholesterol-lowering drug)
  • triglycerides over 150 mg/dl (1.70 mmol/l) (or taking a cholesterol-lowering drug)
  • abdominal fat:  waist circumference 40 inches (102 cm) or greater in a man, 35 inches (89 cm) or greater in a woman
  • fasting blood glucose over 100 mg/dl (5.55 mmol/l)

What To Do About It

Metabolic syndrome and simple excess weight often involve impaired carbohydrate metabolism. Over time, excessive carbohydrate consumption can turn overweight and metabolic syndrome into prediabetes, then type 2 diabetes.  Carbohydrate restriction directly addresses impaired carbohydrate metabolism naturally. When my patients have metabolic syndrome, some of my recommendations are:

  • weight loss, often via a low-carb diet
  • low-carb diet if blood sugars are elevated
  • regular exercise, with a combination of strength and aerobic training

If these work, the patient can often avoid costly drugs and their potential adverse effects.

Ask your doctor what she thinks.

Steve Parker, M.D.

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QOTD: Skyler Tanner on How Much Exercise You Need

I’m a minimalist when it comes to exercise. A really small, really intense dose is all that is needed for the vast majority of people to manifest all of the health benefits that exercise can provide. This does not mean that you can then get away with bed rest in the face of this concentrated dose of exercise, I’m not saying that at all. I’m saying that if a person is living a fairly “normal” life with a decent amount of non-exercise activity built into their day, not a lot of “exercise” is needed above that to maximize health markers.

—Skyler Tanner in a recent blog post (click for the rest)

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Could Resistance Training Replace Slow Steady Cardio?

I was planning to review for you an article, Resistance Training to Momentary Muscular Failure Improves Cardiovascular Fitness in Humans: A review of acute physiological responses and chronic physiological adaptations.  It’s by James Steele, et al, in the Journal of Exercise Physiology (Vol. 15, No. 3, June  2012).

Exercise to momentary muscular failure may be safer on a machine

But it’s too technical for most of my readers. Heck, it’s too technical for me!  Too much cell biology and cell metabolism.  You’re dismissed now.

I’m just going to pull out a few pearls from the article that are important to me.  I ran across this in my quest for efficient exercise.  By efficient, I mean minimal time involved yet still effective.

The authors question the widespread assumption that aerobic and endurance training are both necessary for development of cardiovascular fitness.  Like Dr. Doug McGuff, they wonder if resistance training alone is adequate for the development of cardiovascular fitness.  Their paper is a review of the scientific literature.  The authors say the literature is hampered by an inappropriate definition and control of resistance training intensity.  The only accurate measure of intensity, in their view, is when the exerciser reaches maximal effort or momentary muscular failure.

The authors, by the way, define cardiovascular fitness in terms of maximum oxygen consumption, economy of movement, and lactate threshold.

“It would appear that the most important variable with regards to producing improvement in cardiovascular fitness via resistance training is intensity [i.e., to muscle failure].”

The key to improving cardiovascular fitness with resistance training is high intensity.  These workouts are not what you’d call fun.

From a molecular viewpoint, “the adenosine monophosphate–activated protein kinase pathway (AMPK) is held as the key instigator of endurance adaptations in skeletal muscle.  Contrastingly, the mammalian target of rapamycin pathway (mTOR) induces a cascade of events leading to increased muscle protein synthesis (i.e.,[muscle] hypertrophy).”  Some studies suggest AMPK is an acute inhibitor of mTOR activation.  Others indicate that “resistance training to  failure should result in activation of AMPK through these processes, as well as the subsequent delayed activation of mTOR, which presents a molecular mechanism by which resistance training can produce improvement in cardiovascular fitness, strength, and hypertrophy.”

You’re not still with me, are you?

“… the acute metabolic and molecular responses to resistance training performed to failure appear not to differ from traditional endurance or aerobic training when intensity is appropriately controlled.”

Chronic resistance training to failure induces a reduction in type IIx muscle fiber phenotype and an increase in type I and IIa fibers.  (Click for Wikipedia article on skeletal muscle fiber types.)

“It is very likely that people who are either untrained or not involved in organized sporting competition, but have the desire to improve their cardiovascular fitness may find value in resistance training performed to failure.  In fact, this review suggests that resistance training to failure can produce cardiovascular fitness effects while simultaneously producing improvements in strength, power, and other health and fitness variables. This would present an efficient investment of time as the person would not have to perform several independent training programs for differing aspects of fitness.”  [These statements may not apply to trained athletes.]

Before listing their 157 references, the authors note:

“It is beyond the scope of this review to suggest optimal means of employing resistance training (i.e., load, set volume, and/or frequency) in order to improve cardiovascular fitness since there are no published studies on this topic.”

In conclusion, if you’re going to do resistance training but not traditional aerobic/cardio exercise, you may not be missing out on any health benefits if you train with high  intensity.  And you’ll be done sooner.

Steve Parker, M.D.

PS: See Evidence-based resistance training recommendations by Fisher, Steele, et al.

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What Causes Type 2 Diabetes?

“Beats me. I teach math!”

I have no simple answer for you, unfortunately.

You can lower your risk of type 2 diabetes significantly by avoiding overweight and obesity, by exercising regularly, and by choosing the right parents.  These provide clues as to the causes of diabetes.  The Mediterranean diet also prevents diabetes.

UpToDate.com offers a deceptively simple answer:

Type 2 diabetes mellitus is caused by a combination of varying degrees of insulin resistance and relative insulin deficiency. [Insulin is the pancreas hormone that lowers blood sugar.] Its occurrence most likely represents a complex interaction among many genes and environmental factors, which are different among different populations and individuals.

So, what causes the insulin resistance and relative insulin deficiency?

Understanding the pathogenesis [cause] of type 2 diabetes is complicated by several factors. Patients present with a combination of varying degrees of insulin resistance and relative insulin deficiency, and it is likely that both contribute to type 2 diabetes. Furthermore, each of the clinical features can arise through genetic or environmental influences, making it difficult to determine the exact cause in an individual patient. Moreover, hyperglycemia itself can impair pancreatic beta cell function and exacerbate insulin resistance, leading to a vicious cycle of hyperglycemia causing a worsening metabolic state.

The UpToDate article then drones on for a several thousand words discussing mouse studies, various genes, free fatty acids, adiponectin, leptin, amylin, insulin secretion, insulin resistance, impaired insulin processing, insulin action, body fat distribution, inflammation, various inflammatory markers, low birth weight, high birth rate, prematurity, etc.  More excerpts:

Increased free fatty acid levels, inflammatory cytokines from fat, and oxidative factors, have all been implicated in the pathogenesis of metabolic syndrome, type 2 diabetes, and their cardiovascular complications.

Insulin resistance may, at least in part, be related to substances secreted by adipocytes [fat cells] (“adipokines” including leptin adiponectin, tumor necrosis factor alpha, and resistin).

Type 2 diabetes most likely represents a complex interaction among many genes and environmental factors.

That’s the simplest answer I can give now.

Steve Parker, M.D.

Reference: “The Pathogensis of Type 2 Diabetes Mellitus”  by David K McCulloch, MD, and R Paul Robertson, MD, at UpToDate.com, updated June 2012, and accessed November 19, 2012.

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