Weak, lazy-feeling legs often stem from lifestyle factors like dehydration, poor circulation (sitting too long, smoking), lack of sleep, or overexertion, but can also signal underlying issues like vitamin deficiencies (D, B12), nerve problems (sciatica, neuropathy), anemia, or chronic conditions like diabetes, requiring a doctor's visit if persistent. Addressing hydration, movement, and sleep are quick fixes, but persistent weakness needs medical investigation to rule out serious causes.
If you notice any of these, it's best to reach out to your primary care provider right away. Leg weakness or fatigue can be symptoms of a range of health issues. Some of the most common include: Nerve conditions like sciatica, multiple sclerosis, or peripheral neuropathy.
Guillain-Barre syndrome often begins with tingling and weakness starting in the feet and legs and spreading to the upper body and arms. Some people notice the first symptoms in the arms or face. As Guillain-Barre syndrome progresses, muscle weakness can turn into paralysis.
Neuromuscular diseases
They include muscular dystrophy, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), myasthenia gravis and fibromyalgia. These diseases cause several symptoms, including losing strength in the legs, muscle twitching and muscle stiffness.
On the one hand, blood volume is increased and, on the other hand, the venous walls become more flexible, resulting in the veins expanding. As a consequence, blood may accumulate in the veins, causing symptoms such as heavy, tired legs, water retention and varicose veins.
Symptoms of low blood sugar include feeling shaky, sweaty or hungry, turning paler than usual, or finding it difficult to concentrate. If this happens, test your blood sugar, and treat it straight away if it's low. Find out how to treat low blood sugar.
Nearly a third of pregnant women have a condition called restless legs syndrome (RLS). People who have restless legs syndrome describe it as an "itchy," "pulling," "burning," "creepy-crawly" feeling that gives them an overwhelming urge to move their legs. Once they do move their legs, the feeling often subsides.
Potassium Deficiency (Hypokalaemia)
Hypokalemia is a medical condition that occurs when you have minimal potassium in your blood flow. Potassium deficiency can lead to leg heaviness, leg weakness, leg cramps, constipation, fatigue, and numerous other symptoms.
Early signs of ALS often involve painless muscle weakness, such as tripping or dropping things, along with muscle twitching (fasciculations), cramping, and stiffness (spasticity), commonly starting in limbs but sometimes affecting speech (slurring) or swallowing (choking). Other early indicators include significant fatigue, poor balance, or even uncontrollable laughing/crying (pseudobulbar affect). These symptoms usually begin subtly in one area and spread, affecting daily activities before becoming severe.
Even just a slight electrolyte imbalance can disrupt muscle function, contribute to dehydration, and cause other issues, such as muscle cramping, weakness, or fatigue. If left unaddressed, unbalanced electrolyte levels in the body can also cause more serious health problems, such as heart arrhythmias.
The weakness can make your legs feel heavy, as if they are being weighed down by something. They may also ache and hurt. Some people with MS describe it as like having bags of sand attached to their legs. This muscle weakness combined with MS fatigue can be upsetting.
Neck and limb muscles
Myasthenia gravis also may cause weakness in the neck, arms and legs. These symptoms may happen later as the condition worsens. Weakness in the legs can affect how you walk. Weak neck muscles can make it hard to hold up the head.
Several conditions can make your legs feel weak. Spinal problems like herniated discs, pinched nerves, or spinal stenosis. Poor circulation, vitamin deficiencies, and medication side effects can also make your legs feel weak.
Try these simple ideas:
Essential Vitamins That Can Help Tired Legs & Muscle Function
The first signs of Motor Neurone Disease (MND) often involve muscle weakness, leading to stumbling, a weak grip, or difficulty lifting objects, but can also start with speech/swallowing issues (slurring, choking) or muscle twitching (fasciculations) and cramps. These symptoms are usually mild and painless initially, varying by where the motor neurons are first affected, but often include fatigue and affect limbs or speech/swallowing muscles.
Other nerve conditions can suddenly affect ability to walk such as Guillain-Barré syndrome (a disorder where the immune system attacks the nerves), multiple sclerosis flares, or compressed nerves in the spine.
In limb-onset, the first symptoms will be in the arms or legs and start with weakness, tripping or stumbling or a reduction in fine manual dexterity. In bulbar-onset, the first symptoms will be difficulty in speaking or swallowing.
Weakness in the legs can be caused by many different conditions, including amyotrophic lateral sclerosis (ALS or called Lou Gehrig's disease), bulging/herniated (slipped) disc, Cauda equina syndrome, Guillain-Barré syndrome, autoimmune diseases, multiple sclerosis, Parkinson's disease, peripheral neuropathy, pinched ...
Symptoms of vitamin B12 or folate deficiency
Theories include dehydration, electrolyte imbalances, and muscle fatigue. Some drinks can stop leg cramps when they start. These drinks include electrolyte drinks and coconut water. There's evidence that electrolyte drinks can prevent leg cramps, too, but there isn't a best electrolyte drink for leg cramps.
Leg pain can signal various diseases, often related to poor blood flow (like Peripheral Artery Disease (PAD) or Deep Vein Thrombosis (DVT)), nerve issues (like Sciatica, Diabetic Neuropathy, or Restless Legs Syndrome), joint/bone problems (like Arthritis or infections), or muscle conditions, with symptoms varying from exercise-induced cramping to persistent aching, swelling, or numbness.
Serum ferritin is a peripheral measure of iron that has been found to correlate inversely with RLS symptom severity. 2,3 When serum ferritin level is low, it is postulated that iron levels in the brain will also be low and this may cause or worsen RLS symptoms.
Preeclampsia, formerly called toxemia, happens when you're pregnant and have high blood pressure, too much protein in your pee, and also swelling in your legs, feet, and hands. It can range from mild to severe. It usually happens late in pregnancy, though it can come earlier or just after delivery.