The Surprising Relationship Between Your Calf Muscles and Dementia
What’s the relationship between your calves and your brain?
A diagnosis of dementia and Alzheimer’s disease can be hard to swallow. But what if there was an indication of cognitive decline that could help you prevent these conditions?
Recent studies have shown that leg strength has a direct relationship to your brain health, and could prevent things like brain atrophy and dementia.
Although they are often used interchangeably, dementia and Alzheimer’s disease are two different disorders of the central nervous system.
Dementia is not one specific condition, but an umbrella term for the inability to think clearly, remember, or make decisions (1).
Although dementia is very common among older adults, it is not normal to develop such a drastic cognitive impairment with age.
Dementia can develop for a number of different reasons including age, family history, race and ethnicity, brain injury, or poor heart health.
Symptoms can include problems with memory, attention, communication, or forgetting old memories.
On the other hand, Alzheimer’s disease is a form of dementia that affects the area of the brain that controls new memories, intelligence, judgment, and behavior (1).
In fact, more than half of all people with dementia are diagnosed with Alzheimer’s (1).
Common symptoms of Alzheimer’s are trouble remembering conversations that just happened, personality changes, or difficulty talking.
There are various causes of Alzheimer’s, but family history is the most common cause of this problem.
Other types of dementia include vascular dementia, Lewy Body dementia, and frontotemporal dementia. Differentiation of the conditions can be difficult, so anyone experiencing signs or symptoms must seek a doctor’s opinion.
Unfortunately, there are no current medications or treatments for cognitive decline conditions like dementia.
As mentioned before, new studies are indicating that we may be able to improve our cognitive abilities before things like dementia and Alzheimer’s develop.
Researchers have shown that there is a direct relationship between blood pressure and calf strength with brain health.
Blood Pressure and the Brain
Blood pressure is the amount of pressure that blood exerts on the artery walls. Blood pressure is often tested to see how well blood flows and to make sure that the brain, heart, and skeletal muscles are receiving enough blood to function.
Blood pressure is measured with two different numbers.
The top number is the systolic blood pressure (SBP). Systolic blood pressure indicates how much pressure is placed on the artery wall when the heartbeats.
The bottom number or diastolic blood pressure measures the pressure when the heart is at rest.
Typically, medical professionals often pay more attention to the SBP because it is an indicator of cardiovascular disease. SBP usually rises steadily with age due to the rigidity of arteries and a buildup of plaque on the blood vessel walls.
Hypertension, or high blood pressure, can lead to a variety of poor outcomes. For example, stroke, heart attack, and heart disease are common side effects of chronic hypertension.
High blood pressure is caused for a variety of reasons including poor diet, inactivity, obesity, or other stressors (both physical and mental). Medical treatment can include medication or a regular workout program.
Although hypertension is very common, low blood pressure can also have poor effects on our wellbeing and quality of life.
Blood pressure that is too low can actually cause a variety of milder symptoms, and can also contribute to poor quality of life.
For example, blood pressure that is too low can cause physical symptoms like dizziness, weakness, numbness or fainting, and cause a cascade of other health problems.
Severely low blood pressure can also deprive your body of the necessary oxygen that it needs and can cause damage to the brain, which we’ll discuss shortly.
Symptoms of low bp can arise for a variety of reasons including age, hypertension medications, and certain chronic diseases like Parkinson’s or diabetes (2).
Low Blood Pressure and Dementia
Before we relate calf strength to chronic diseases like dementia or Alzheimer’s, it’s important to understand orthostatic hypotension.
Orthostatic hypotension is defined as a blood pressure drop after standing up. This condition doesn’t necessarily have any underlying causes but can affect cognitive function.
Not to be confused with dehydration, orthostatic hypotension is more common in older adults with mild cognitive impairment and dementia (3).
A study (3) was done to analyze the link between orthostatic hypotension and cognitive impairments. The scientists looked at data from a memory clinic, where patients with dementia, mild cognitive decline, and subjective cognitive decline were treated.
Each patient had their blood pressure measured once laying down, and twice after standing.
The study showed that orthostatic hypotension was present in 19% of the patients with subjective cognitive decline, 28% of the patients with mild cognitive decline, and 41% of the patients with dementia (3).
So how is the calf muscle related to all of this?
The Calf Muscles
The vascular system can act as a “second heart” for our bodies in a way. The veins in our calves act as a reservoir for blood that doesn’t need to be circulated at that time. These veins are called venous sinuses (4).
When the calf muscle contracts during physical activity, the blood is pushed along the venous system towards the heart and brain.
Let’s take a look at the anatomy of the calf.
At the bottom half of the back of your leg, there are two prominent leg muscles: the gastrocnemius and the soleus.
The gastrocnemius is a bigger muscle and sits next to the fibula (a small lower leg bone) that helps to point your toes and bend the knee to help you move forward. Often times this muscle creates a “muscle bulge” when contracted.
The soleus is a smaller muscle in the lower leg that also helps point your toes but sits on the outer edge of the lower leg.
When these calf muscles are contracted, they squeeze the blood reservoir to open the pathway to help pump blood through our bodies.
When this mechanism isn’t working to its fullest potential, it can cause blood pooling, stroke, claudication, and other health consequences.
Weak legs or muscle atrophy in the calves can be detrimental to our health for this reason.
Skeletal Muscle Atrophy
Muscle atrophy, or loss of muscle tissue, is an umbrella term that stands for the gradual loss of skeletal muscle.
There are a few different causes of muscle atrophy, for example:
Disuse Atrophy
Disuse atrophy occurs when a muscle is not used or challenged for a long period of time.
When our muscles are used, the small muscle fibers are damaged and repaired, thus making them bigger and stronger.
This process is called muscle hypertrophy. Disuse atrophy is common in older people with a sedentary lifestyle, or those with paralysis, spinal cord injury, or prolonged bed rest.
Interestingly, astronauts often experience an accelerated rate of muscle atrophy because they spend time in space with no gravity to challenge their skeletal muscles.
Cachexia
Cachexia is defined as weight loss due to an underlying condition and causes muscle wasting in the skeletal muscle. Cachexia can occur because of:
- anorexia
- malnutrition (poor nutrition)
- starvation
- or cancer
If our muscles don’t receive the nutrients they need, the muscle fibers will waste away and become weaker.
Those with any sudden loss of muscle mass should seek medical attention immediately.
Sarcopenia
Sarcopenia is another common cause of muscle atrophy. Sarcopenia is the gradual loss of skeletal muscle mass and strength through the breakdown of muscle fibers.
Just like any other muscle in the body, skeletal muscle fibers will only grow if they are stimulated and challenged.
A sedentary lifestyle is another risk factor for sarcopenia. Similarly, age-related sarcopenia is common in older adults.
Disuse atrophy, cachexia, and sarcopenia can all cause complications in our vascular system.
Because our lower legs play such a vital role in our heart and brain health, it is important to consider the clinical outcomes that a high degree of muscle loss can cause.
For example, dysfunctions in the pathophysiology of the calf can include:
- vericose veins (enlarged, tangles of veins)
- claudication (sharp pain in the back of the leg)
- deep vein thrombosis (result of a blood clot in the deep veins of the leg)
- stroke
- heart attack
- sepsis
- inflammation
Luckily, atrophy and muscle weakness can be reversed.
How to Stop Muscle Loss in the Calves
Effective treatment for increasing skeletal muscle mass should include resistance training.
Resistance training is a physical activity that involves weights, resistance bands, or fighting the weight of gravity.
Regular resistance exercise can cause muscle hypertrophy and improve strength in the given muscle group.
When starting any new physical activity routine, it is important to consult a physical therapist.
Any person with a preexisting medical condition that limits exercise (COPD, severe cases of muscle weakness, muscular dystrophy, ALS, etc.) may benefit from physical therapy.
Exercises that will help to build muscle strength in the gastrocnemius and soleus are seated or standing calf raises.
Standing Calf Raise
Stand on a slightly elevated surface like a stair or curb and place the ball of your foot on the edge with your heel hanging off.
Slowly raise to stand on your toes, then lower back down and repeat.
Repeat this process for 3 sets of 10 reps.
Seated Calf Raise
Sit in a chair so that your knees are at hip height and place something heavy on your knees (textbook, dumbbell, etc.).
Slowly raise your heels until only the balls of your feet are on the floor, then lower back down.
Repeat this process for 3 sets of 10 reps.
Not only are these exercises great for sufficient blood flow, but can also help with muscle growth and reduce pain related to Achilles tendinitis.
Resistance exercise is great for building new muscle tissue, hypertrophy, and prevent the loss of muscle mass.
For those who cannot perform regular exercise, functional electrical stimulation may be a great option, if advised by your physical therapist.
Functional electrical stimulation is a form of involuntary contraction of skeletal muscle fibers by placing sensors on the muscle. It is often used as a home treatment!
Always consult a doctor to prevent any serious risk.
Summary
As we now know, there is a direct association between the physical function of the calf muscles and proper brain function.
Dementia,
Alzheimer’s and Parkinson’s are all scary diagnoses, but research has found that there may be early signs of detection for brain function decline hiding in the back of your leg.
Because healthy BP plays such a vital role in brain changes and health, it is important to do all we can to stay healthy and lower dementia risk.
Let’s recap:
High blood pressure can put a person at risk for heart attack, stroke, narrowing of blood vessels, or cardiovascular disease. While a high SBP and DBP can be dangerous, blood pressure that is too low can also cause health issues.
In the article we discussed, the participants with hypotension (low blood pressure) also had a high rate of some sort of cognitive decline (3).
Because the calf muscles can regulate blood flow to the brain, loss of muscle mass in the lower leg can be detrimental.
Physical inactivity has become an epidemic and can lead to unfavorable health outcomes like an unhealthy body mass index, obesity, slow metabolism, and more (all risk factors for early mortality).
Little did we know, lack of physical activity, especially in the lower leg, can affect the physical function of the brain.
Regular exercise has so many benefits like fat loss, reduced symptoms of depression, improved muscle strength and increased lean muscle mass, increased lifespan–and now, we know: cognitive function.
With this new information, it is incredibly important for young adults, middle-aged adults, and the elderly to engage in regular resistance exercise to potentially change the way our brain works.
References
- “What Is Dementia?” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 5 Apr. 2019, www.cdc.gov/aging/dementia/index.html.
- “Low Blood Pressure (Hypotension).” Mayo Clinic, Mayo Foundation for Medical Education and Research, 22 Sept. 2020, www.mayoclinic.org/diseases-conditions/low-blood-pressure/symptoms-causes/syc-20355465
- Kleipool, Emma E F et al. “Orthostatic Hypotension: An Important Risk Factor for Clinical Progression to Mild Cognitive Impairment or Dementia. The Amsterdam Dementia Cohort.” Journal of Alzheimer’s disease : JAD vol. 71,1 (2019): 317-325. doi:10.3233/JAD-190402
- “Blogyour Second Heart.” Vein Atlanta Your Second Heart Comments, veinatlanta.com/your-second-heart/