Cold Feet and Herniated Discs: Understanding the Connection and All Possible Causes

Your nervous system plays a crucial role in how your feet feel. Sensory nerves detect temperature changes and send signals to your brain, while autonomic nerves control the diameter of blood vessels in your feet. When blood vessels constrict (narrow), less warm blood reaches your feet, making them feel cold. When they dilate (widen), more blood flows through, warming the feet. 

Damage or dysfunction in either type of nerve, whether from spinal compression, metabolic conditions such as diabetes, or other causes, can disrupt this delicate balance, leading to cold feet even when the environmental temperature is comfortable. 

Your spine consists of vertebrae separated by intervertebral discs that act as shock absorbers. Each disc has a tough outer layer (annulus fibrosus) and a gel-like center (nucleus pulposus). A herniated disc occurs when the outer layer tears or weakens, allowing the inner material to bulge out or leak through the tear. 

In the lumbar spine, the most common sites for disc herniation are L4-L5 (between the fourth and fifth lumbar vertebrae) and L5-S1 (between the fifth lumbar vertebra and the first sacral vertebra). These levels are particularly susceptible because they bear the most mechanical stress during daily activities. 

It's a common misconception that herniated discs cause symptoms purely through mechanical compression, the disc pressing on a nerve. While compression can occur, research has revealed that chemical inflammation is often the primary pain generator.¹ 

When a disc herniates, inflammatory chemicals are released into the surrounding tissues. These substances, including prostaglandins, cytokines (particularly TNF-alpha and IL-6), proteolytic enzymes, and substance P, irritate nearby nerve roots, making them hypersensitive. This inflammation can affect both sensory and autonomic nerve fibers. 

For the feet, specifically, the affected nerve roots carry fibers that control blood vessel diameter in the lower extremities. When these autonomic fibers are compromised by inflammation or compression, the blood vessels may not dilate properly, reducing blood flow and causing the feet to feel persistently cold. 

L4-L5 disc herniation (affecting L5 nerve root): 

• Pain radiating down the outer thigh and leg 
• Numbness on top of the foot and between the first and second toes 
• Cold sensation in the foot, particularly on the dorsal (top) surface 
• Weakness lifting the foot upward (foot drop in severe cases) 

L5-S1 disc herniation (affecting S1 nerve root): 

• Pain traveling down the back of the thigh and calf 
• Numbness on the bottom of the foot and outer toes 
• Cold sensation in the foot, especially the sole and lateral (outer) border 
• Weakness pushing up on tiptoes 

Here's an important point that's often misunderstood: not all herniated discs cause symptoms. Research shows that 30-84% of people without any back pain have disc abnormalities visible on MRI scans.² The presence of a herniated disc doesn't automatically mean it's causing your cold feet or other symptoms. 

What matters is whether the specific disc herniation is generating significant inflammation or compression that disrupts nerve function. Some herniations may be small, contained, or positioned in a way that doesn't affect nearby nerves. Others may be large but not inflammatory. This is why accurate diagnosis, correlating imaging findings with clinical symptoms, is essential.³ 

Diabetic peripheral neuropathy is one of the most common causes of cold feet and affects approximately 50% of people with diabetes.⁴ This condition develops when chronically elevated blood sugar levels damage the small blood vessels that supply nerves, particularly in the extremities. 

How it causes cold feet: 

High glucose levels trigger several damaging processes: oxidative stress, formation of advanced glycation end products (AGEs), and inflammation that damages nerve fibers. Both sensory nerves (which detect temperature) and autonomic nerves (which control blood vessel diameter) are affected, leading to abnormal temperature sensation and reduced blood flow to the feet. 

Recent research: 

A 2022 study published in Diabetes Care found that intensive glucose control significantly reduces the progression of diabetic neuropathy. The study demonstrated that patients who maintained HbA1c levels below 7% had a lower risk of developing severe neuropathic symptoms, including cold feet, compared to those with poor glucose control.⁵ 

Additional symptoms: 

• Burning, tingling, or shooting pain in the feet (often worse at night) 
• Progressive numbness that starts in the toes and moves upward 
• Sensitivity to touch or inability to feel minor injuries 
• Loss of balance and coordination 

Peripheral artery disease occurs when atherosclerotic plaque builds up in the arteries that supply blood to the legs and feet. This narrows the arteries, reducing blood flow and oxygen delivery to the lower extremities. PAD affects over 12 million Americans, with prevalence increasing significantly after age 50.⁶ 

How it causes cold feet: 

When arteries are narrowed or blocked, insufficient warm blood reaches the feet. This reduction in blood flow is most noticeable during activity (when muscles need more oxygen) and in cold environments. Severe PAD can cause persistently cold feet even at rest. 

Recent research: 

The 2024 ACC/AHA guidelines on the management of lower extremity peripheral artery disease emphasize that cold feet are an important but often overlooked symptom. The guidelines note that many patients with PAD don't experience classic claudication (leg pain with walking) but do report chronic cold feet. Early detection through ankle-brachial index (ABI) testing is recommended for high-risk individuals.⁷ 

Risk factors for PAD: 

• Smoking (the single most important modifiable risk factor) 
• Diabetes 
• High blood pressure and high cholesterol 
• Age over 50 
• Family history of vascular disease 

Additional symptoms: 

• Leg pain or cramping with walking that improves with rest (intermittent claudication) 
• Weak or absent pulses in the feet 
• Shiny skin on the legs, hair loss on the legs/feet 
• Wounds or sores on the feet that heal slowly or not at all 

Raynaud's phenomenon is a condition in which small arteries in the fingers and toes spasm in response to cold temperatures or emotional stress, temporarily reducing blood flow. While it most commonly affects the hands, it can also impact the feet, causing them to feel intensely cold and change color (typically white, then blue, then red as blood flow returns). 

There are two types: primary Raynaud's (occurring on its own) and secondary Raynaud's (associated with underlying conditions like scleroderma, lupus, or rheumatoid arthritis). 

Recent research: 

A 2023 study in Nature Genetics identified novel genetic risk factors for Raynaud's phenomenon, providing new insights into why some people develop this condition. The research found that genetic variants affecting vascular smooth muscle function and adrenergic receptor sensitivity significantly increase susceptibility to vascular spasms. This discovery may lead to more targeted treatments in the future.⁸ 

Characteristic symptoms: 

• Episodic cold feet triggered by cold exposure or stress 
• Color changes: white (pallor) → blue (cyanosis) → red (reperfusion) 
• Numbness or tingling during episodes 
• Pain or throbbing as blood flow returns 

Hypothyroidism occurs when the thyroid gland doesn't produce enough thyroid hormones. These hormones regulate metabolism throughout the body, including heat production and circulation. When thyroid hormone levels are low, metabolic rate decreases, reducing the body's ability to generate and distribute heat. 

How it causes cold feet: 

Low thyroid hormones slow circulation and reduce metabolic heat production. The body prioritizes blood flow to vital organs, often at the expense of the extremities. Additionally, hypothyroidism can cause peripheral vasoconstriction (narrowing of blood vessels in the arms and legs), further reducing blood flow to the feet. 

Additional symptoms of hypothyroidism: 

• Fatigue and weakness 
• Weight gain despite no change in diet 
• Sensitivity to cold throughout the body (not just feet) 
• Dry skin and hair loss 
• Constipation and depression 

Anemia is a condition in which you don't have enough healthy red blood cells to carry adequate oxygen to your body's tissues. Since red blood cells also help transport heat throughout the body, anemia can contribute to cold extremities, particularly the feet and hands. 

The most common causes of anemia include iron deficiency, vitamin B12 deficiency, folate deficiency, chronic kidney disease, and chronic inflammatory conditions. In severe anemia, the body may redirect blood flow away from the extremities to ensure vital organs receive adequate oxygen. 

Symptoms of anemia: 

• Persistent fatigue and weakness 
• Pale skin, nail beds, or mucous membranes 
• Shortness of breath with exertion 
• Rapid or irregular heartbeat 
• Dizziness or lightheadedness 

While venous insufficiency primarily affects blood return from the legs to the heart, recent research has identified connections between venous disease and cold feet. Chronic venous insufficiency occurs when valves in leg veins fail to work properly, causing blood to pool in the lower legs. 

Recent research: 

In 2025, a group examined the relationship between varicose veins and cold feet sensation. The study found that patients with varicose veins were significantly more likely to report cold feet than controls, possibly due to disrupted microcirculation and impaired venous return, which can affect arterial inflow. The research suggests that treating varicose veins may improve cold feet symptoms in some patients.⁹ 

Associated symptoms: 

• Visible, bulging varicose veins 
• Leg heaviness, aching, or fatigue (especially after prolonged standing) 
• Swelling in the ankles and feet 
• Skin changes, including discoloration or thickening 

Certain medications can cause cold feet as a side effect by affecting blood flow, vascular tone, or nerve function. If you started experiencing cold feet shortly after beginning a new medication, this could be the culprit. 

Common medication classes that may cause cold feet: 

• Beta-blockers (used for high blood pressure and heart conditions): These medications can reduce blood flow to the extremities by blocking beta receptors that normally promote vasodilation. 
• Ergot preparations (used for migraines): These drugs cause vasoconstriction and should be used cautiously. 
• Chemotherapy drugs: Some chemotherapy agents can cause peripheral neuropathy, leading to cold sensations in the feet. 
• Decongestants containing pseudoephedrine: These over-the-counter medications cause vasoconstriction throughout the body. 

Several lifestyle factors can contribute to cold feet, often in combination with underlying medical conditions: 

Smoking: Nicotine causes vasoconstriction and damages blood vessel walls, significantly reducing circulation to the extremities. Smoking also accelerates the development of peripheral artery disease. 

Physical inactivity: Lack of exercise leads to poor circulation, weakened blood vessels, and reduced cardiovascular fitness, all of which can contribute to cold feet. 

Prolonged sitting or standing: Maintaining the same position for extended periods impairs circulation and can lead to pooling of blood in the lower legs. 

Tight footwear or socks: Constrictive clothing around the feet or ankles can reduce blood flow, causing cold feet. 

Stress and anxiety: Chronic stress activates the sympathetic nervous system, which can lead to vasoconstriction and reduced blood flow to the extremities. This is particularly relevant in people with Raynaud's phenomenon. 

At Deuk Spine Institute, we emphasize that accurate diagnosis requires three components working together: 

• Clinical history: A thorough discussion of your symptoms, including when the cold feet started, what makes them better or worse, what other symptoms you're experiencing, your medical history, current medications, and lifestyle factors. 
• Physical examination: A comprehensive exam including neurological testing (sensation, strength, reflexes), vascular assessment (checking pulses, skin color, temperature, capillary refill), spine examination (for signs of nerve root compression), and evaluation of overall health status. 
• Diagnostic testing: Appropriate tests based on clinical suspicion, which may include imaging studies, blood tests, vascular studies, or nerve conduction studies. 

If a herniated disc is suspected as the cause of cold feet, specific diagnostic steps are necessary: 

MRI Imaging: Magnetic resonance imaging is the gold standard for visualizing herniated discs. MRI can show the location, size, and type of disc herniation; whether nerve roots are compressed; the degree of disc degeneration; and the presence of inflammation in surrounding tissues. 

However, it's crucial to understand that imaging alone is not sufficient for diagnosis. Research consistently shows that many people without symptoms have disc abnormalities on MRI. What matters is correlation, does the disc abnormality seen on imaging match your symptoms and physical examination findings? 

Physical Examination: Specific tests can help identify which nerve root is affected: 

• Straight leg raise test: Reproduces leg pain when a herniated disc is compressing a nerve root 
• Neurological examination: Tests sensation, strength, and reflexes in specific nerve root distributions 
• Provocative maneuvers: Certain positions or movements that reproduce symptoms help confirm the diagnosis 

Electrodiagnostic Studies (EMG/NCS): These tests measure electrical activity in muscles and nerves, confirming the presence and severity of nerve compression, identifying which specific nerve root is affected, and distinguishing spinal radiculopathy from peripheral nerve problems. 

Depending on clinical suspicion, additional tests may be necessary: 

Blood tests: Complete blood count (for anemia), fasting glucose and HbA1c (for diabetes), thyroid function tests (TSH, T3, T4), vitamin B12 and folate levels, and inflammatory markers (if autoimmune disease suspected). 

Vascular studies: Ankle-brachial index (ABI) to screen for peripheral artery disease, Doppler ultrasound to assess blood flow in leg arteries and veins, and angiography if severe vascular disease is suspected. 

Nerve conduction studies: If peripheral neuropathy is suspected (as in diabetic neuropathy), these tests measure how well nerves transmit electrical signals. 

Given the complexity of diagnosing the root cause of cold feet, particularly when spinal issues are involved, seeking a second opinion is often valuable. This is especially true if: 

• You've been diagnosed with a herniated disc and recommended for surgery, but want to explore all options 
• Your symptoms don't seem to match the diagnosis you've received 
• Conservative treatments haven't provided relief 
• You want confirmation that all potential causes have been thoroughly investigated 
• You're considering different treatment approaches 
• A second opinion can provide: 
• Confirmation that your diagnosis is accurate and correlates with your imaging findings 
• Alternative perspectives on treatment options you may not have been offered 
• Identification of overlooked factors contributing to your symptoms 
• Peace of mind that you're making informed decisions about your care 

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• Physical therapy: Strengthening core muscles, improving flexibility, and learning proper body mechanics 
• Medications: NSAIDs to reduce inflammation, muscle relaxants for spasm relief, neuropathic pain medications (gabapentin, pregabalin) if nerve symptoms are significant 
• Epidural steroid injections: Targeted delivery of anti-inflammatory medication around affected nerve roots 
• Activity modification: Avoiding positions and activities that exacerbate symptoms 

While conservative treatments can help manage symptoms, they rarely address the root cause, the inflamed disc tissue itself. For many patients, these approaches provide only temporary relief. 

When conservative care fails, traditional surgery is often recommended. Common procedures include microdiscectomy (removing the herniated portion of the disc), laminectomy (removing bone to decompress nerves), and spinal fusion (permanently joining vertebrae together).¹⁰ 

However, traditional surgeries come with significant drawbacks: invasiveness (often requiring cutting through muscle and bone), risk of complications, prolonged recovery time, and, in the case of fusion, permanent loss of spinal motion that can lead to adjacent segment disease. 

Deuk Laser Disc Repair® (DLDR) is an advanced endoscopic procedure that addresses herniated discs while preserving your spine's natural structure and function. Unlike fusion, DLDR® requires no screws, rods, or metal implants. 

How DLDR® works: 

• A tiny incision (less than ¼ inch) is made 
• A tubular retractor gently spreads muscle to create a surgical corridor 
• An endoscopic camera provides high-definition visualization 
• A medical laser precisely removes only the inflammatory disc tissue through the annular tear 
• Healthy disc structure remains intact, preserving natural spinal motion 

Key advantages: 

• Outpatient procedure (patients go home the same day) 
• Rapid recovery (walking within an hour, return to light activities within days) 
• No fusion (natural spinal motion preserved) 
• No bone removal (spinal stability maintained) 
• Minimal scarring (less than ¼ inch incision) 
• 99.6% patient reported success rate with zero complications in over 2,700 procedures 

Diabetic Neuropathy: 

• Strict blood glucose control (the most important intervention) 
• Medications for neuropathic pain: gabapentin, pregabalin, duloxetine 
• Regular foot care and daily inspection to prevent ulcers 
• Alpha-lipoic acid supplementation (may provide modest benefit) 

Peripheral Artery Disease: 

• Smoking cessation (absolutely essential) 
• Supervised exercise therapy (walking programs improve symptoms) 
• Medications: antiplatelet agents (aspirin, clopidogrel), statins to lower cholesterol 
• Revascularization procedures (angioplasty, stenting, or bypass surgery) for severe disease 

Raynaud's Phenomenon: 

• Avoiding cold exposure and wearing warm socks/shoes 
• Stress management techniques 
• Calcium channel blockers (nifedipine) to reduce vascular spasm 
• Biofeedback therapy 

Anemia: 

• Iron supplementation for iron-deficiency anemia 
• Vitamin B12 injections or oral supplementation 
• Treatment of underlying cause (kidney disease, chronic inflammation, etc.) 

Hypothyroidism: 

Thyroid hormone replacement therapy (levothyroxine) with regular monitoring 

Excess body weight increases mechanical stress on the lumbar spine, raising the risk of disc herniation. Obesity also contributes to metabolic conditions like diabetes and worsens circulation. For individuals who are overweight, losing even 5-10% of body weight can significantly reduce symptoms and improve overall health. 

Regular exercise improves circulation, strengthens core muscles that support the spine, helps maintain healthy blood sugar levels, and promotes overall cardiovascular health. Low-impact activities like walking, swimming, cycling, and yoga are particularly beneficial. Aim for at least 150 minutes of moderate-intensity aerobic activity per week, plus strength training twice weekly. 

Important: If you have a herniated disc or other spinal condition, work with a physical therapist to develop an appropriate exercise program that won't exacerbate your symptoms. 

Protecting your spine from injury requires attention to how you move throughout the day: 

• Lifting technique: Bend at the knees (not the waist), keep objects close to your body, avoid twisting while lifting, and use your leg muscles to generate power 
• Sitting posture: Use lumbar support, keep feet flat on the floor, position monitors at eye level, and take regular breaks to stand and move 
• Sleeping position: Side sleeping with a pillow between the knees or back sleeping with a pillow under the knees; avoid stomach sleeping 
• Workstation setup: Ensure proper ergonomics, whether working from home or in an office 

Smoking is one of the most significant modifiable risk factors for cold feet. Nicotine causes vasoconstriction, damages blood vessel walls, accelerates disc degeneration, impairs healing, and dramatically increases the risk of peripheral artery disease. Quitting smoking provides benefits for circulation within weeks and continues to improve vascular health over time. 

For people with diabetes or prediabetes, maintaining tight glucose control is essential for preventing diabetic neuropathy. This includes regularly monitoring blood sugar, taking medications as prescribed, following a balanced diet low in refined carbohydrates, exercising regularly, and maintaining a healthy weight. Aim for HbA1c levels below 7% (or as directed by your physician). 

Controlling risk factors for vascular disease helps prevent peripheral artery disease and improves overall circulation: 

• Control blood pressure (target <130/80 mmHg for most people) 
• Manage cholesterol levels (statins if indicated) 
• Maintain a heart-healthy diet rich in vegetables, fruits, whole grains, and lean protein 
• Limit alcohol consumption 

Proper footwear protects your feet and promotes good circulation. Choose shoes with adequate toe room, good arch support, and cushioned soles. Avoid tight shoes or boots that constrict blood flow. In cold weather, wear warm, moisture-wicking socks (but avoid socks with tight elastic bands). For people with diabetes, special diabetic shoes may be recommended to prevent foot injuries. 

Proper hydration supports disc health and overall circulation. Additionally, certain nutrients are particularly important for nerve and vascular health: 

• B vitamins (especially B12, B6, folate) for nerve function 
• Omega-3 fatty acids for vascular health and anti-inflammatory effects 
• Magnesium for nerve and muscle function 
• Antioxidants (vitamins C and E) to protect nerves and blood vessels 

Chronic stress activates the sympathetic nervous system, which can cause vasoconstriction and worsen cold feet, particularly in people with Raynaud's phenomenon. Stress management techniques such as meditation, deep breathing exercises, regular exercise, adequate sleep, and cognitive-behavioral therapy can help reduce stress-related symptoms. 

Early detection of conditions that cause cold feet allows for prompt treatment and can prevent progression. Regular health screenings should include blood pressure checks, diabetes screening (fasting glucose or HbA1c), a cholesterol panel, thyroid function tests (if symptoms suggest hypothyroidism), a complete blood count (to screen for anemia), and a vascular assessment (ankle-brachial index) for high-risk individuals. 

A: The key is looking at the full clinical picture. If your cold feet are accompanied by lower back pain radiating into the leg, numbness or tingling following a specific nerve distribution (like the top of the foot or the sole), weakness in specific leg muscles, and symptoms that worsen with certain positions or activities, a herniated disc may be the cause. However, if your cold feet are bilateral (affecting both feet equally), are associated with other systemic symptoms (fatigue, weight changes, other circulation problems), or are not accompanied by back pain or radicular symptoms, other causes such as diabetes, thyroid disease, or vascular problems are more likely. A comprehensive evaluation by a healthcare provider, including appropriate imaging and testing, is necessary for accurate diagnosis. 

A: While cold feet are often benign and related to environmental factors or minor circulation issues, they can sometimes indicate serious underlying conditions. Warning signs that warrant immediate medical attention include sudden onset of severe cold sensation in one foot, cold feet accompanied by leg pain, skin color changes, or wounds that won't heal (suggesting severe vascular disease), progressive weakness or numbness, cold feet with chest pain or shortness of breath (possible heart problems), and bowel or bladder dysfunction alongside cold feet and back pain (cauda equina syndrome, a medical emergency). If you experience any of these symptoms, seek medical care promptly. 

A: The timeline for improvement depends on the underlying cause and the treatment approach. For herniated disc-related cold feet, conservative treatment may provide improvement within 6-12 weeks, though some cases take longer. Minimally invasive procedures like Deuk Laser Disc Repair® typically provide rapid relief; many patients notice improvement within days to weeks. For diabetic neuropathy, improvement requires consistent blood sugar control over months; some nerve damage may be irreversible if long-standing. For peripheral artery disease, revascularization procedures can provide relatively quick improvement in blood flow, though the timeline varies. For hypothyroidism, thyroid hormone replacement typically improves symptoms within 4-8 weeks. For Raynaud's phenomenon, avoiding triggers and medications can reduce episode frequency, but complete resolution is variable. The key is addressing the root cause consistently and following your treatment plan as directed. 

A: Yes, several home strategies can provide symptom relief and support overall foot health: Wear warm, moisture-wicking socks and well-fitting shoes. Avoid tight elastic bands that restrict circulation. Use warm (not hot) water for foot soaks, then thoroughly dry. Massage your feet to promote blood flow. Elevate your feet when sitting for extended periods. Stay active; regular walking improves circulation. Avoid smoking and limit caffeine, both of which constrict blood vessels. Practice stress-reduction techniques if you have Raynaud's. Maintain good hydration. Use layered bedding and keep your bedroom at a comfortable temperature. However, these measures complement, but don't replace, medical treatment for underlying conditions. Always consult your healthcare provider for persistent or worsening cold feet. 

A: Unilateral (one-sided) cold feet are more concerning than bilateral cold feet because they suggest a localized problem rather than a systemic condition. If only one foot is cold, possible causes include a herniated disc compressing a specific nerve root on one side, peripheral artery disease with blockage in one leg, deep vein thrombosis (blood clot), injury or trauma to nerves or blood vessels in one leg, or nerve entrapment. Sudden onset of cold sensation in one foot, especially if accompanied by pain, color changes, or weakness, requires prompt medical evaluation to rule out serious vascular or neurological problems. 

A: Physical therapy can be beneficial for managing symptoms related to herniated discs, including cold feet, though it typically doesn't provide a permanent cure. A well-designed physical therapy program can strengthen core muscles to better support the spine, improve flexibility and range of motion, teach proper body mechanics to prevent further injury, use manual therapy techniques to reduce muscle tension, and incorporate nerve gliding exercises to improve nerve mobility. However, physical therapy cannot reverse a disc herniation or remove inflamed disc tissue. For some patients, physical therapy provides adequate symptom relief. For others, especially those with significant disc herniation and inflammation, more definitive treatment may be necessary. The effectiveness of physical therapy depends on the size and location of the herniation, the degree of nerve compression or inflammation, and individual factors. Working with a physical therapist who specializes in spinal conditions is important for optimal outcomes. 

A: While there can be overlap, some distinguishing features help differentiate these causes. Cold feet from vascular (circulation) problems typically present with feet that are actually cold to the touch, skin that may appear pale or bluish, symptoms that worsen with elevation and improve with lowering the feet, possible hair loss on legs/feet, weak or absent pulses, and may be accompanied by intermittent claudication (leg pain with walking). Cold feet from nerve problems typically present with a sensation of coldness that may not correspond to actual skin temperature, numbness or altered sensation in specific nerve distributions, symptoms may follow a dermatomal pattern (matching specific nerve roots), possible associated weakness in specific muscles, and symptoms that may worsen with certain positions or activities that affect nerve roots. That said, some conditions (like diabetes) can cause both nerve damage and vascular problems simultaneously, making differentiation more complex. This is why a comprehensive evaluation, including vascular studies (ABI, Doppler ultrasound) and neurological testing (EMG/NCS), may be necessary. 

1: https://www.sciencedirect.com/science/article/pii/S000709121732963X 

2: https://pmc.ncbi.nlm.nih.gov/articles/PMC4464797 

3: https://deukspine.com/blog/l3-l4-l5-disc-bulge-treatment 

4: https://www.ncbi.nlm.nih.gov/books/NBK442009 

5: https://pmc.ncbi.nlm.nih.gov/articles/PMC9056490/ 

6: https://www.ahajournals.org/doi/10.1161/CIR.0000000000001153 

7: https://www.ahajournals.org/doi/10.1161/CIR.0000000000001251 

8: https://www.labroots.com/trending/genetics-and-genomics/25787/genetic-cause-raynaud-s-phenomenon-revealed 

9: https://bmjgroup.com/symptoms-of-ice-cold-feet-heaviness-in-legs-strongly-linked-to-varicose-veins 

10: https://deukspine.com/blog/lumbar-laminectomy-surgery-for-back-pain 

11: https://deukspine.com/blog/l5-s1-disc-herniation-guide