Exercise 30 minutes once a week sufficient to improve risk factors

Posted on May 3, 2011 by Dr. Jonathan

It doesn’t take much to make a big difference. A study published in the journal Medicine & Science in Sports & Exercise shows that modest doses of eccentric exercise in particular are sufficient to improve metabolic and cardiovascular risk factors. The authors compared the effects of eccentric (muscles lengthen while resisting) to concentric exercise:

“The effects of chronic eccentric-only versus concentric-only exercise on muscle physiology and blood biochemistry were investigated.”

The authors had their subjects either concentric exercise on an isokinetic dynamometer eccentric exercise using the knee extensors of both legs once a week for eight subsequent weeks. In addition to parameters of muscle function, they measured body fat, resting energy expenditure (REE); the lipid and carbohydrate oxidation rate along with blood chemistry measurements (lipid, lipoprotein and apolipoprotein profile, glucose, insulin, glycosylated hemoglobin, and creatine kinase) before and 48 hours after exercise on the first and eighth weeks of training. What did the data show?

“Acute [measured immediately after] eccentric exercise increased REE and fat oxidation at week 1 (12.7% and 12.9%, respectively) and at week 8 (0.7% and 2.8%, respectively). Chronic [measured 48 hours after] eccentric exercise increased resting REE and fat oxidation at week 8 compared with week 1 (5.0% and 9.9%, respectively). Acute eccentric exercise improved blood lipid profile at week 1 and week 8. Chronic eccentric exercise improved resting blood lipid profile at week 8. Acute eccentric exercise increased insulin resistance at week 1 but not at week 8. Chronic eccentric exercise decreased resting insulin resistance at week 8.”

It’s impressive to see how so little can do so much. The authors’ offer a welcome conclusion:

“It is reported for the first time that only 30 min of eccentric exercise per week for 8 wk was sufficient to improve health risk factors.”

Static stretching worsens endurance exercise performance

Posted on November 19, 2010 by Dr. Jonathan

You may already know that static stretching impairs high force and velocity athletic performance, but a study published recently in the Journal of Strength and Conditioning Research provides evidence that static stretching worsens muscle endurance performance too.

“Stretching before anaerobic events has resulted in declines in performance; however, the immediate effects of stretching on endurance performance have not been investigated. This study investigated the effects of static stretching on energy cost and endurance performance in trained male runners.”

The authors examined trained male distance runners oxygen utilization, calorie expenditure and performance in distance running with and without stretching beforehand. The data were unambiguous:

“Performance was significantly greater in the nonstretching vs. the stretching condition, with significantly greater energy expenditure during the stretching compared with the nonstretching condition. Our findings suggest that stretching before an endurance event may lower endurance performance and increase the energy cost of running.”

How might this occur? Static stretching seems to decrease mechanical efficiency of the muscle system by causing the muscle tissue to work harder to produce the same amount of force. The authors further elaborated on their findings:

“In summary, this study provides 2 key findings concerning endurance performance after a bout of static stretching. First, it extends the detrimental effects of stretching from activities requiring high force and velocity components to the domain of muscle endurance performance. Second, this research suggests that static stretching increases the energy cost of running at moderate-intensity exercise. Therefore, in events such as long-distance running, where success is related to producing work with minimal energy cost, it may be unfavorable for coaches to have athletes warm up in a manner that has them perform long, static stretches immediately before a middle- or long-distance running event.”

Exercise scores as well as Zoloft for major depression

Posted on October 28, 2010 by Dr. Jonathan

Another outcome study to add to the massive body of evidence that the psychopharmaceutical model for treating depression is seriously flawed was published in the journal Psychosomatic Medicine. The authors pitted sertraline (Zoloft, an SSRI) against exercise and placebo as they set out to…

“…assess whether patients receiving aerobic exercisetraining performed either at home or in a supervised group settingachieve reductions in depression comparable to standard antidepressantmedication (sertraline) and greater reductions in depressioncompared to placebo controls.”

They randomly assigned 202 adults diagnosed with major depression were to either supervised exercise in a group setting; home-based exercise; antidepressant medication (sertraline, 50–200 mg daily); or placebo pill for 16 weeks. This was followed by a structured clinical interview for depression and completed the Hamilton Depression Rating Scale (HAM-D). Typically, the data showed little difference between the placebo and Zoloft, and virtually no difference between the medication and exercise:

“After 4 months of treatment, 41% of the participants achieved remission, defined as no longer meeting the criteria for major depressive disorder (MDD) and a HAM-D score of <8. Patients receiving active treatments tended to have higher remission rates than the placebo controls: supervised exercise = 45%; home-based exercise = 40%; medication = 47%; placebo = 31%. All treatment groups had lower HAM-D scores after treatment; scores for the active treatment groups were not significantly different from the placebo group.”

There is an enormous amount of science showing that this class of medications profoundly perturbs the brain in such a way that attempting to stop taking them after 6 weeks or continuing them long-term can result in the dismal trap of a brain sensitized to depression. This study would have been even more striking had they compared the unmedicated exercise group to those who were medicated after attempting to stop. As it is, the authors conclude:

“The efficacy of exercise in patients seems generally comparable with patients receiving antidepressant medication and both tend to be better than the placebo in patients with MDD. Placebo response rates were high, suggesting that a considerable portion of the therapeutic response is determined by patient expectations, ongoing symptom monitoring, attention, and other nonspecific factors.”

Historically, before the age of psychopharmaceuticals most cases of major depression tended to be self-limiting. For an objective, meticulous, articulate and gripping scientific and historical narrative on how anti-depressants, tranquilizers and anti-psychotic medications have promoted the skyrocketing levels of mental disability, I suggest Anatomy of an Epidemic by Robert Whitaker. Anyone considering taking or prescribing these medications should be aware of the science reviewed comprehensively in this text.

Walking helps prevent brain atrophy and dementia

Posted on October 21, 2010 by Dr. Jonathan

Not only does walking for exercise have favorable metabolic and hormonal effects; a study just published in the journal Neurology provides evidence that it is a beneficial stimulus to the brain. The authors state:

“Here we tested whether PA [physical activity] would be associated with greater gray matter volume after a 9-year follow-up, a threshold could be identified for the amount of walking necessary to spare gray matter volume, and greater gray matter volume associated with PA would be associated with a reduced risk for cognitive impairment 13 years after the PA evaluation.”

They examined 299 adults for the the association between gray matter volume, physical activity (quantified as the number of blocks walked per week), and cognitive impairment. After 9 years high-resolution brain scans were acquired. Examination for cognitive impairment was done 13 years after the start of the study. What did the data show?

“Greater PA predicted greater volumes of frontal, occipital, entorhinal, and hippocampal regions 9 years later. Walking 72 blocks [per week] was necessary to detect increased gray matter volume but walking more than 72 blocks did not spare additional volume. Greater gray matter volume with PA reduced the risk for cognitive impairment 2-fold.“

The authors summarized the evidence by concluding:

“Greater amounts of walking are associated with greater gray matter volume, which is in turn associated with a reduced risk of cognitive impairment.“

Bicycle riding and erectile dysfunction

Posted on July 24, 2010 by Dr. Jonathan

The standard bicycle seat can deliver a significant insult to the nerve and blood vessel supply to the male genitalia. There have been numerous studies investigating the relationship between bicycle riding and erectile dysfunction. The authors of a paper published a while back in The Journal of Sexual Medicine that reviewed the science set out to:

“…summarize accumulating data on the safety of bicycle riding based on medical evidence categorized by levels of evidence, including case reports, observational studies, case control studies, mechanistic studies, and population-based epidemiologic investigations. The secondary aim was to address the concerns of bicyclists and propose measures to minimize the risk of ED associated with bicycle riding.”

The mass of data revealed a clear picture and yielded specific recommendations:

“Bicycle riding more than 3 hours per week was an independent relative risk for moderate to severe ED. Therefore, bicycle riders should take precautionary measures to minimize the risk of ED associated with bicycle riding: change the bicycle saddle with a protruding nose to a noseless seat, change the posture to a more upright/reclining position, change the material of the saddle (GEL), and tilt the saddle/seat downwards.”

The authors note in their conclusion:

“Straddling bicycle saddles with a nose extension is associated with suprasystolic perineal compression pressures, temporarily occluding penile perfusion and potentially inducing endothelial injury and vasculogenic ED.”

In a subsequent paper published in the same journal this year the authors revisit the problem and begin by noting:

“For many years, reports in the literature have implicated bicycle riding as causing increased risk of erectile dysfunction (ED). Perineal compression during cycling has been associated with the development of sexual complications.”

They conducted a comprehensive review of the scientific literature and found that further studies had firmly established the risk of cycling-related sexual dysfunction and extended it to females:

“There is a significant relationship between cycling-induced perineal compression leading to vascular, endothelial, and neurogenic dysfunction in men and the development of ED. Research on female bicyclists is very limited but indicates the same impairment as in male bicyclists.”

The authors of a review published earlier in European Urology caution practitioners to be aware of this widespread phenomenon. They report that a range of problems have been documented:

“The most common bicycling associated urogenital problems are nerve entrapment syndromes presenting as genitalia numbness, which is reported in 50–91% of the cyclists, followed by erectile dysfunction reported in 13–24%. Other less common symptoms include priapism, penile thrombosis, infertility, hematuria, torsion of spermatic cord, prostatitis, perineal nodular induration and elevated serum PSA, which are reported only sporadically.”

They conclude by exhorting practitioners to be alert:

“Urologists should be aware that bicycling is a potential and not an infrequent cause of a variety of urological and andrological disorders caused by overuse injuries affecting the genitourinary system.”

Perhaps this could contribute, at least to some degree, occurrences of ‘cyclist road rage’. Are there any remedies or recommendations for cyclists to follow? Another study in The Journal of Sexual Medicine investigated the condition in police officers:

“The average bicycle police officer spends 24 hours a week on his bicycle and previous studies have shown riding a bicycle with a traditional (nosed) saddle has been associated with urogenital paresthesia and sexual dysfunction.”

The officers manifested the typical problems, but also demonstrated some improvement when using a ‘no-nose saddle’:

“(i) With few exceptions, bicycle police officers were able to effectively use no-nose saddles in their police work. (ii) Use of no-nose saddles reduced most perineal pressure. (iii) Penile health improved after 6 month using no-nose saddles as measured by biothesiometry and IIEF. There was no improvement in Rigiscan® [nocturnal erection] measure after 6 months of using no nose saddles, suggesting that a longer recovery time may be needed.”

It only makes anatomical sense that insult to the nerves and blood vessels that supply the genitalia could cause sexual dysfunction in both males and females.

Barefoot beats running shoes for injury prevention

Posted on January 30, 2010 by Dr. Jonathan

Nature 012310 Research recently published in the prestigious journal Nature validates assertions popularized in the book Born To Run that running barefoot, or in minimal shoes, results in less running injuries. The investigators observed that…

“Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers.”

They go on to state:

“Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.”

Whatever the kind of shoe or barefoot the key point seems to be forefoot versus heel strike. There’s an interesting report on the study in Nature News and another in ScienceNOW (from the journal Science).

Qigong benefits type 2 diabetes

Posted on January 25, 2010 by Dr. Jonathan

This randomized controlled study recently published in the journal Diabetes Care (the journal of the American Diabetes Association) nicely validates the recommendation of qigong exercises as a treatment adjunct for type 2 diabetes. The investigators used fasting glucose, insulin, hemoglobin A1C and calculated insulin resistance as metrics to determine efficacy. Their conclusion: “Qigong therapy for 12 weeks resulted in significant reductions in fasting glucose levels in patients with type 2 diabetes and demonstrated trends toward improvement in insulin resistance and A1C. These results suggest that Qigong may be an effective complementary therapy for individuals with type 2 diabetes.”

Resistance exercise necessary for weight management and metabolic control

Posted on January 23, 2010 by Dr. Jonathan

Diabetes Care Aerobic exercise, especially if performed in an interval fashion (see earlier posts) is very good, but don’t leave out the high-intensity resistance (“strength”) training for improving body composition which, of course, depends on metabolic control. This timely paper recently published in the journal Diabetes Care confirms that high-intensity resistance exercise does something that other forms of exercise don’t. Adiponectin is hormone critical for burning rather than storing fat; higher levels are better. The investigators found that “Adiponectin concentration increased after 12 h and remained elevated for 24 h only in the high-intensity group.” They go on to conclude: “Resistance exercise does increase REE and adiponectin in an intensity-dependent manner for as long as 48 and 24 h, respectively, in overweight elderly individuals. It appears that resistance exercise may represent an effective approach for weight management and metabolic control…” [REE = resting energy expenditure]

By the way, if you are suffering from rheumatoid arthritis or another inflammatory disorder is it safe and effective for you to do high-intensity resistance training? According to this study published in the journal Arthritis Care & Research, the answer is yes. The investigators set out “To confirm, in a randomized controlled trial (RCT), the efficacy of high-intensity progressive resistance training (PRT) in restoring muscle mass and function in patients with rheumatoid arthritis (RA).” Their conclusion: “In an RCT, 24 weeks of PRT proved safe and effective in restoring lean mass and function in patients with RA…PRT should feature in disease management.”

Moderate-intensity exercise more effective than vigorous intensity for cardiovascular risk

Posted on December 4, 2009 by Dr. Jonathan

A surprising paper of great practical significance was just published in the journal Obesity that documents a significantly greater improvement in cardiovascular risk-related variables (triglycerides, insulin, metabolic syndrome score) with moderate-intensity exercise than with vigorous exercise. The authors offer this life-style pearl: “That all three of these strong, independent, cardiovascular risk factors were significantly affected by moderate-intensity exercise suggests that regular walking exercise might be as effective, if not more so, than more vigorous exercise in favorably modifying cardiovascular risk.” Further research will have to validate my expectation that the adrenocortical stress response plays a role here. Don’t forget the importance of interval training (see earlier posts), but at least get out for a walk.

Slow walking speed linked to cardiovascular death

Posted on November 21, 2009 by Dr. Jonathan

Not intended to ‘crack the whip’, this study just published in the British Medical Journal concludes: “Slow walking speed in older people is strongly associated with an increased risk of cardiovascular mortality.” It’s important to understand that when the elderly walk more slowly or have trouble with balance it is because of neurodegeneration, a brain problem. The connection is not just that the brain needs oxygen (from blood pumped by the heart)—neurodegeneration includes less control of inflammation, blood pressure, adrenal circadian rhythm, etc.