How to Reduce Swelling? Causes of Leg Swelling, Lower Limb Edema, and Calf Swelling + 7 Ways to Reduce Water Retention [Hong Kong Guide 2026]

If the sock marks from the morning haven't disappeared, your shoelaces feel too tight by evening, or pressing your ankle leaves a dimple that takes several seconds to spring back… these are all warning signs of leg swelling. For Hong Kong people who sit or stand all day in the office, sweat little leading to fluid retention, and have a heavy-flavored diet, lower limb edema is almost an urban ailment. This article, compiled by the DR-HO'S Hong Kong Health Editorial Team, delves into the 8 major causes of edema, the difference between single and double leg swelling, red flag symptoms, and introduces 7 methods for reducing edema (acupressure/dietary therapy/stretching/TENS electrical therapy/leg elevation). Finally, we review the practical help that DR-HO'S Circulation Promoter offers in improving circulation and reducing edema.

What is Edema? What's Happening in Your Body?

Edema (medically known as "Edema") refers to the accumulation of excessive tissue fluid in the interstitial spaces under the skin, most commonly in the lower limbs (calves/feet/ankles). Normally, arteries deliver blood to tissues, and the venous and lymphatic systems return fluid; when this balance is disrupted – for example, due to poor circulation, high vascular pressure, or lymphatic blockage – fluid gets retained, and pressing the skin leaves a dimple.

Edema is not a disease itself, but rather a body signal – indicating potential issues with lower limb circulation, the lymphatic system, or organ function. Mild physiological edema (due to prolonged sitting/pre-menstruation/high-salt meals) is not a cause for concern; however, persistent, sudden, unilateral edema, especially when accompanied by pain or skin discoloration, should raise an alarm.

Types of Edema: Unilateral vs. Bilateral, Pitting vs. Non-Pitting

The classification of edema directly determines its underlying cause. The two most important axes are:

8 Common Causes of Edema

The most frequently asked questions by Hong Kong people, "causes of leg swelling" and "causes of single leg swelling", actually stem from the following 8 main causes.

1️⃣ Prolonged Sitting/Standing & Poor Circulation (Most Common, over 60% of cases)

Maintaining the same posture for a long time prevents the calf muscles from pumping, leading to poor blood and lymphatic return. Office workers sitting all day, waiters standing all day, and long-haul flights lasting over ten hours – all fall under this mechanism. No symptoms in the morning, but swelling starts in the evening is a typical characteristic. For detailed circulation knowledge, please refer to the Complete Guide to Improving Blood Circulation.

2️⃣ Sodium / Fluid Intake Imbalance

Sodium causes the body to retain water. Hong Kong people often eat out, consuming instant noodles, barbecued meats, and noodle soups – a single meal can easily exceed the recommended sodium intake. Conversely, drinking too little water can also make the body want to retain more water. It is recommended to drink 1.5-2 liters of water daily and consume a low-sodium diet.

3️⃣ Hormonal Cycle (Women)

5-7 days before menstruation, progesterone causes the body to retain water, potentially leading to mild edema in the legs, abdomen, fingers, and face. This usually subsides automatically when menstruation begins. Edema in pregnant women, particularly "pregnant leg swelling" and "pregnant edema", is very common due to the uterus pressing on the inferior vena cava, and is mostly physiological.

4️⃣ Varicose Veins & Venous Insufficiency

Damage to the valves in the leg veins leads to impaired blood return. Typical symptoms: spider veins/blue-purple veins on the calves + leg swelling + aching/heaviness. Common in the elderly, pregnant women, and those who stand for long periods at work.

5️⃣ Lymphatic System Problems (Lymphedema)

When lymphatic vessels are blocked or damaged (due to surgery, infection, or congenital conditions), tissue fluid cannot return to the bloodstream. Typical characteristics: non-pitting, firm, and does not subside with rest. Commonly seen as arm swelling after breast cancer surgery or lower limb swelling after gynecological surgery.

6️⃣ Abnormal Heart, Kidney, or Liver Function

Heart failure (right-sided heart failure) causes blood to pool in the lower limbs; kidney disease leads to protein loss and low plasma colloid osmotic pressure; liver disease results in reduced albumin production. This type of edema is often accompanied by shortness of breath, reduced urination, and abdominal distension, requiring immediate medical attention.

7️⃣ Medication Side Effects

Common medications that can cause edema include: calcium channel blockers (for high blood pressure), NSAIDs (anti-inflammatory painkillers), corticosteroids, certain diabetes medications, and birth control pills. If new swelling appears suddenly after starting a new medication, you should inform your doctor/pharmacist and never stop the medication on your own.

8️⃣ Localized Problems: Infection, Sprain, Gout, Deep Vein Thrombosis

Sudden unilateral leg swelling accompanied by pain and redness/warmth should prompt ruling out:

• Gout attack: Severe pain, redness, and swelling in the toes or feet, often due to high uric acid (refer to Guide to Toe Pain)
• Sprain/Ankle twist: Swelling after ankle joint trauma
• Cellulitis: Bacterial infection, causing redness, warmth, and fever
• Deep Vein Thrombosis (DVT): Severe leg pain + redness/warmth + sudden swelling, an emergency

Who is Most Prone to Edema? High-Risk Groups

3-Second Self-Check: What Level of Edema Do You Have?

The "thumb press test" can immediately assess the severity of edema: Press your thumb for 5 seconds on the medial side of the tibia (next to the shin bone), then observe how long the indentation takes to rebound.

7 Methods to Reduce Edema (Do at Home)

For the most common "lifestyle-induced" bilateral lower limb edema, combining the following 7 methods can show results within 2 weeks.

1️⃣ Elevate Your Legs (Simplest and Most Effective)

While sleeping or resting, elevate your legs 15-20cm above your heart, for 15-30 minutes each time, 2-3 times a day. This uses gravity to help fluid return. You can use pillows to prop up your legs or lie on your back with your legs against a wall in a "banana" pose.

2️⃣ Wear Compression Stockings (Medical Grade)

Wear compression stockings with a pressure level of 15-20 mmHg before standing/sitting and remove them after work. Suitable for those with prolonged standing/sitting, mild varicose veins, and cabin crew. Note: Individuals with heart failure, severe diabetes, or skin ulcers should consult a doctor first.

3️⃣ Control Sodium Intake

Daily sodium intake should be ≤ 2,000mg (equivalent to 5g of salt). Avoid: instant noodles, barbecued meats, canned foods, potato chips, excessive soy sauce, processed meats. Eat more potassium-rich foods (bananas, potatoes, oranges, spinach) to help excrete sodium.

4️⃣ Drink More Water (Counter-intuitive but Effective)

Insufficient hydration can actually cause the body to retain water. Drink 1.5-2 liters of water daily in small, frequent sips, avoiding large amounts at once. You can add a few lemon slices or weak tea.

5️⃣ Calf Pump Exercises (Can be Done in the Office)

While sitting, perform "heel raises" + "toe raises", 20 repetitions each, every hour for 1 set. The contraction and relaxation of the calf muscles act like a pump, assisting blood and lymphatic return.

6️⃣ Lymphatic Drainage Massage (Manual or Tool)

Using your palm or a roller, gently push from the distal end (ankle) towards the proximal end (groin) for 5-10 minutes on each side. Remember: the pressure should be light (a gliding sensation on the skin) and not deep. Deep pressure only increases tissue damage.

7️⃣ TENS/EMS Electrical Stimulation for Circulation

Home-use electrical therapy devices stimulate calf muscles to passively contract through low-frequency electrical currents, acting like an "automatic calf pump." This is particularly helpful for those who sit or stand for long periods, the elderly, and pregnant women (who should consult a doctor first). Use for 20-40 minutes daily. The next section will introduce DR-HO'S Circulation Promoter.

5 Acupoints for Edema Relief (Traditional Chinese Medicine Perspective)

For "acupoints for edema relief," a common query among Hong Kong people, here are 5 clinically used acupoints that are easy to locate and press yourself. Press each point for 1-2 minutes, 1-2 times a day.

How Can DR-HO'S Circulation Promoter Help You?

For recurrent lower limb edema, poor circulation due to prolonged sitting/standing, and early stages of varicose veins, home-use TENS/EMS electrical therapy devices are among the most popular at-home relief solutions for Hong Kong people in 2026.

Advanced Version: Professional Circulation Promoter (CPP)

If, in addition to edema, there are also elderly individuals with foot numbness, cramps, knee pain, or back pain, the upgraded DR-HO'S Professional Circulation Promoter can be considered. It features Dr. Michael Ho's patented AMP technology + TENS/EMS/NMES all-in-one, with dual independent output ports for simultaneous treatment of two areas, and comes with exclusive knee support accessories. For details, refer to the AMP Patented Technology Guide.

Also Recommended: MotionCiser

DR-HO'S MotionCiser features a "Get fit while you sit" design – when sitting for office work or watching TV, place your feet on it, and the machine automatically simulates slow walking movements, passively promoting lower limb circulation. This is particularly effective for long-term office workers and elderly individuals with edema.

Red Flags: 5 Situations Requiring Immediate Medical Attention

Additionally, if it involves medications such as "edema-reducing pills," it is advisable to follow a doctor's/pharmacist's guidance. Do not take diuretics on your own, as they can cause electrolyte imbalance and lead to cramps (refer to Complete Guide to Cramps).

Frequently Asked Questions FAQ

Q1: Why are my feet fine in the morning but so swollen at night that I can't wear shoes?

This is typical "gravitational" bilateral edema – in the morning, body fluid is evenly distributed, but after standing/sitting all day, fluid accumulates in the lower limbs due to gravity. Key treatments: elevate legs for 15 minutes in the evening, wear compression stockings, use TENS electrical therapy to stimulate the calf pump, and reduce salt intake. Improvement is usually seen within 2 weeks.

Q2: Is leg swelling normal during pregnancy? How should it be managed?

Leg swelling that occurs in the mid-to-late stages of pregnancy (after 28 weeks), is bilateral, worsens in the evening, and resolves with rest, is mostly physiological. Management: sleep on your left side (to reduce uterine pressure on the inferior vena cava), elevate legs, walk moderately, and wear compression stockings. However, if there is sudden severe unilateral swelling + high blood pressure + proteinuria → beware of preeclampsia, seek immediate medical attention. Consult an obstetrician before using TENS electrical therapy.

Q3: What is the difference between "edema" and "fat"?

Edema involves pitting when pressed, significant daily fluctuations, and short-term weight changes of 2-3 kg; obesity is fat, no pitting when pressed, slow changes, and long-term stability. If you weigh 2 kg less in the morning and haven't been dieting → it's likely edema from the night before.

Q4: Will drinking too much water cause edema?

Under normal circumstances, drinking more water actually helps excrete sodium and reduce edema (because the kidneys can excrete excess water). However, patients with heart failure or severe kidney disease must control fluid intake (as advised by a doctor). It is recommended for general individuals to drink 1.5-2 liters of water daily, in small, frequent sips.

Q5: How effective is DR-HO'S Circulation Promoter for edema?

TENS/EMS electrical therapy stimulates calf muscles to passively contract, mimicking a "calf pump" to aid venous and lymphatic return. It provides substantial relief for lower limb edema in office workers who sit/stand for long periods, the elderly, and postpartum edema. It is recommended to use it for 20-30 minutes after dinner or during rest, combined with leg elevation and salt reduction, and observe the effects for 2-4 consecutive weeks. However, edema caused by heart, kidney, or liver diseases must be treated by addressing the underlying condition first.

Q6: How to differentiate between edema and lymphedema?

The key is the "Stemmer sign": Use your thumb and index finger to pinch the skin on your toes or fingers. With normal edema, you can lift a fold of skin; with lymphedema, you cannot lift the skin (the skin becomes firm and thickened). Lymphedema requires specialized lymphatic drainage treatment, and TENS electrical therapy may have limited help.

✍️ Written by: DR-HO'S Hong Kong Health Editorial Team
🩺 Content Consultant: Dr. Michael Ho (Registered Chiropractor in Canada)
📅 Last Updated: May 2026