By Dr. Joseph Mercola | mercola.com
STORY AT-A-GLANCE
- In animal research, rats have overcome mild cognitive impairment through resistance training
- Resistance training enables neurogenesis, the production of new neurons. It may also assist in the prevention and management of Type 2 diabetes
- By reducing resting blood pressure and increasing high-density lipoprotein cholesterol, resistance training may enhance cardiovascular health
- Bone mineral density and low back pain may improve with resistance training
- Data from clinical trials show that elderly people with depression have improvement with resistance training
Exercise, along with nutritious eating, is the best health practice you can adopt. By increasing blood flow to your brain and reducing damaging brain plaques, it can help prevent and even reverse neurological diseases, including Alzheimer's disease.
Research shows resistance training, also called resistance or strength training, offers special benefits to the brain not seen with aerobic exercise, especially in preventing mild cognitive impairment (MCI), which is often a prelude to Alzheimer's disease. In fact, some research suggests muscular strength may be used as an actual indicator of imminent MCI, so closely correlated are muscle strength and brain health.1
A recent study in the Journal of Applied Physiology2 found rats that did resistance training actually changed their brain's cellular environment, improving their ability to think. The rats overcame lab-induced mild cognitive impairment — and their brains exhibited enzymes and genetic markers linked to new neurons and increased plasticity from resistance training.
In addition to newly identified brain benefits, resistance training improves the overall quality of life and helps with everyday activities, so it's a win-win.
Resistance Training Improved Rats' Brains
How can rats be made to engage in resistance training? Researchers taped bags of weighted pellets to the rats' hind ends3 and enticed them into climbing a 3-foot ladder for a reward at the end of their climb. The climbing rats increased their muscle mass, an expected result that is known to occur with resistance training.
Researchers then injected some animals with lipopolysaccharides to create brain inflammation; this mimicked mild cognitive impairment or early dementia in humans. The animals continued their training.
The resistance-trained rats with MCI and rats with neither feature were then placed in a maze to determine their cognitive abilities. This is how The New York Times described what happened:4
“In the first few tests, the control animals were the fastest and most accurate, and the rodents with mild cognitive impairments faltered. With a little practice, though, the resistance-trained animals, despite their induced cognitive impairments, caught up to and in some cases surpassed the speed and accuracy of the controls.”
How Might Resistance Training Overcome MCI?
Resistance training “can activate IGF-1 downstream signaling and increase proliferation marker PCNA,” suggest the researchers. What does that mean in layman's language?
It means that insulin-like growth factor one (IGF-1) affects substances like PCNA (proliferating cell nuclear antigen), co-factors of a DNA enzyme complex — so the body's actual DNA is likely influenced in a positive way.5
Well-developed muscles also have higher levels of an enzyme that helps metabolize a stress chemical called kynurenine.6 Stress and depression are known risk factors for dementia and Alzheimer's disease.
Weight training also lowers the activity of the bone-morphogenetic protein (BMP),7 a substance that reduces neurogenesis, i.e., the production of new brain cells. High levels of BMP, not surprisingly, make our brains sluggish, and resistance weight training appears to be able to reverse this.
Other Research Confirms Resistance Training's Effects
The unique cognitive benefits of resistance training versus those of aerobic training in humans have been well documented in the medical literature. Here's what researchers writing in the journal CNS & Neurological Disorders-Drug Targets wrote:8
“Some evidence shows that aerobic training can attenuate the aging effects on brain structures and functions. However, strength exercise effects are poorly discussed. Thus, in the present study, the effects of strength training on the brain in elderly people and Alzheimer's disease (AD) patients were revised. Furthermore, a biological explanation relating to strength training effects on the brain is proposed.
Brain atrophy can be related to neurotransmission dysfunction, like oxidative stress, that generates mitochondrial damage and reduced brain metabolism. Another mechanism is related to amyloid deposition and amyloid tangles, that can be related to reductions on insulin-like growth factor I concentrations.
The brain-derived neurotrophic factor also presents reduction during the aging process and AD. These neuronal dysfunctions are also related to cerebral blood flow decline that influences brain metabolism. All of these alterations contribute to cognitive impairment and AD.
After a long period of strength training, the oxidative stress can be reduced, the brain-derived neurotrophic factor and insulin-like growth factor I serum concentrations enhance, and the cognitive performance improves.
Considering these results, we can infer that strength training can be related to increased neurogenesis, neuroplasticity and, consequently, counteracts aging effects on the brain. The effect of strength training as an additional treatment of AD needs further investigation.”
Resistance Training Helps With Glucose Metabolism
Skeletal muscle is the most abundant tissue comprising about 40% of your body mass,9 and is the primary site of insulin-mediated glucose disposal. Muscle is responsible for the majority of the glucose that is used after eating,10 with about 80% of glucose being deposited and stored in skeletal muscle.11
The loss of muscle mass with advancing age is thought to be a primary driver of insulin resistance in older adults. Declining muscle strength and progressive mobility impairment likely cause a reduction in daily physical activity, which also contributes to metabolic dysfunction.12
Muscle is the major site for insulin-stimulated glucose uptake as well as the main energy consumer of fat.13 Blood flow restriction (BFR) training (discussed further below), has been shown to improve insulin sensitivity,14 which is enormously helpful since about 80% of the U.S. population is insulin resistant when using an oral glucose tolerance challenge.15,16,17
Other Resistance Training Benefits
The cognitive benefits of resistance training, especially in reversing, reducing or preventing MCI, are a relatively new field of study. Benefits besides “brainpower,” on the other hand, have been documented for years. As noted in the journal Current Sports Medicine Reports:18
“Resistance training may enhance cardiovascular health, by reducing resting blood pressure, decreasing low-density lipoprotein cholesterol and triglycerides, and increasing high-density lipoprotein cholesterol.
Resistance training may promote bone development, with studies showing a 1% to 3% increase in bone mineral density. Resistance training may be effective for reducing low back pain and easing discomfort associated with arthritis and fibromyalgia and has been shown to reverse specific aging factors in skeletal muscle.”
Strength training stimulates the development of bone osteoblasts, cells that “remodel” or strengthen and build bones that have become weakened or are at risk of weakening. Big Pharma has exploited the fear of thin bones to sell bisphosphonate drugs such as Fosamax and Boniva.
But the ill-conceived drug class does the exact opposite of strength training: these drugs suppress your body's bone-remodeling action leading to brittle, ossified bones prone to fracture — an action that some doctors predicted before the drugs were aggressively marketed.19
Resistance Training Can Be a Natural Antidepressant
The ability of aerobic exercise to work as a natural antidepressant is well known; millions of people know that when they feel the “blues,” a good workout can help. But strength training can also lift your mood, research shows.
“There's a different high when you make a lift or complete your program that day,” says Li Faustino, a New York City clinical psychologist treating people with depression.20
“When you're in a depression, you're ruminating and worrying and fuming and feeling bad and second-guessing, and it's all mental,” says Kelly Coffey, a personal trainer in Northampton, Massachusetts, who began lifting weights to deal with her own depression. “It's this trap that lifting weights safely has to lift you out of.”
One study, which included 32 participants ages 60 to 84, tested the hypothesis that “progressive resistance training (PRT) would reduce depression while improving physiologic capacity, quality of life, morale, function, and self-efficacy without adverse events in an older, significantly depressed population.” Researchers found that depression did indeed lift in the subjects. What're more, positive results correlated to the intensity of the training.21
Resistance Training Is Easy to Do and Inexpensive
Readers of my newsletter know that I am a critic of Big Pharma's overmedication of people when natural treatments are available — which they usually are. The use of resistance training to prevent or address mild cognitive impairment is a case in point. Not only does such training present few risks when done correctly, but it also represents small costs compared to high priced drugs. Before you get started, please check with your doctor if you:
- Are a senior citizen who previously has not been physically active
- Are currently dealing with a serious illness
- Have a chronic condition, such as low-back pain or a bad knee
Here are some of the easy ways you can incorporate resistance training into your life:
| Bodyweight exercises — pushups, planks, and squats |
| Hand weights — inexpensive and portable |
| Medicine balls — use a number of different muscle groups for maneuvering |
| Resistance machines — if you have access to a fitness center or gym |
| Rope or rock-wall climbing — good for abs, arms, back, hands, shoulders, agility, and coordination |
| Strength classes at a fitness center or gyms — such as BOSU ball, Forza, Pilates, Smart Bells, Urban Rebounding and water-based exercise |
| Kettlebells — allow movements not possible with traditional weights |
Boost Benefits With Blood Flow Restriction Training
Another technique you may want to try — which is also excellent for the elderly and for athletes recovering from an injury — is blood flow restriction training or Kaatsu training. For more in-depth details, see my interview with Jim Stray-Gundersen, a leading proponent and teacher of Kaatsu in the U.S.
In brief, it involves performing strength training exercises while restricting venous blood flow return to the heart (but not arterial flow) to the extremity being worked. A significant benefit of the method is that you can do strength exercises using just 20% of the max weight you'd normally be able to lift while still reaping maximum benefits.
By restricting blood flow to the muscle, lactic acid and other waste products build-up, giving you the same benefit as heavy lifting but without the dangers associated with heavyweights. For this reason, it's a great strategy for the elderly and those who are recuperating from an injury.
Put another way, by forcing blood to remain inside your muscle longer than normal, you force more rapid muscle fatigue and muscle failure that sets into motion subsequent repair and regeneration processes. It actually increases blood flow to the type II muscle fiber stem cells that are responsible for increasing muscle growth and strength.
Blood flow restriction training can stimulate muscle growth and strength in about half the time, using about one-fifth of the weight, compared to standard weight training. This makes it more available to seniors.
A typical training session would involve three sets, with 30 repetitions per set, and only resting for 15 seconds when the bands are on the arms and 30 seconds when they are on the legs.
According to Stray-Gundersen, while the American College of Sports Medicine claims you need to lift a weight that is at least 65-90% of your single repetition max (1RM) to produce muscle growth, studies assessing low-intensity exercise in combination with blood flow restriction have shown you can go as low as 20% of 1RM and still reap the benefits.
For most, 20% of 1RM is lighter than a warmup, virtually guaranteeing you will not sustain any kind of injury. Indeed, blood flow restriction training is used to rehabilitate the elderly and infirm in Japan, allowing them to rebuild muscle and regain some of their lost mobility.
