It is not unexpected for our legs to feel tired after standing for long hours, walking further than we are accustomed to or running distances beyond our conditioning. In these cases the tired feeling is due to muscle fatigue and strain. It usually eases within a several hours to a few days depending on the severity and is unlikely to arise again unless there are other strenuous episodes.
However, when the legs feel tired despite there being no clearly identifiable event then it must be medically investigated. It is possible that leg tiredness or fatigue is a symptom of some disease. The tiredness may be accompanied by other symptoms and diagnostic investigations may sometime sbe necessary to identify the underlying cause.
Why do the legs feel tired?
Tired legs is a way that most people will describe fatigue of the lower limb. This is is largely due to strain on the structures of the lower limbs, namely the muscles and joints. It may cause an ache, soreness, burning sensation or even pain. A person may feel unstable when standing or walking, experience tremors or muscle weakness and may feel the urge to rest their legs or feet.
Tiredness of the legs occurs for largely the same reasons as other parts of the body. The muscles make up a large part of the lower limbs (thighs, lower legs and feet). These muscles contract and relax to facilitate movement. However, the muscle’s ability to contract and relax over long periods of time and with greater force can eventually cause fatigue.
The onset of muscle fatigue depends on several factors, including level of activity, duration and individual conditioning. Also motion (walking or running) causes muscle fatigue faster, even standing can lead to fatigue. Furthermore, one person may be able to stand for an hour and not experience tired legs while another person may experience fatigue in a much shorter period of time.
Causes of Tired Legs
There are a host of different causes of a tired feeling in the legs. Sometimes common sensations like soreness or even pain may be described as tired legs. Not all of these causes are serious but sometimes an innocuous sensation like tired legs can be the early symptom of serious diseases.
Tired legs should be investigated by a medical professional when it is persistent, occurs despite any obvious physical strain, and is accompanied by symptoms like pain, numbness or weakness. Many of the same causes of leg pain may also be responsible for a feeling of tired legs.
Read more on lower leg pain.
This is the most common cause of a tired feeling in the legs. Every person will experience leg exertion and fatigue many times throughout life with overuse of the muscles, tendons and joints. The feeling eases once the strain eases with sufficient rest. However, in most cases the leg muscles, tendons and joints can adapt with repeated exertion and eventually result in better condition and the inability to withstand longer periods of strain.
Muscle cramps or spasms are sudden and forceful contraction of the muscles. It is common in the legs and while overuse and strain are the most common causes, cramps can also occur for other reasons. Hormone fluctuations, nutritional deficiencies as well as some of the other causes discussed below like circulatory problems.
Growing pains is a common problem among children. The exact cause for this pain is unclear but it does appear to be due to growth, despite its name. Sometimes aches and pains due to exertion can be mistaken for growing pains. Furthermore this type of pain may be linked to restless leg syndrome. However, in most cases it appears that overuse of the legs which is typical in children who tend to be very active is the most likely cause for growing pains.
Several circulatory conditions may cause a tired feeling in the legs. These conditions may involve either the arteries or veins of the legs. Peripheral arterial disease (PAD) is where an artery of the lower limb is narrowed due to a fatty plaque (atherosclerosis). Blood flow to lower parts of the leg is therefore restricted. Symptoms are most prominent when there is increased leg muscle activity.
Vein problems may involve the superficial or deep leg veins. Varicose veins is where the superficial leg veins become distended and the valves within it becomes less competent. Blood from the leg cannot rise up to the torso as effectively. In deep vein thrombosis (DVT), a blood clot forms in the deep leg vein. This clot can dislodge and eventually obstruct vessels of the lungs.
Arthritis is another common leg condition where joints become inflamed. Although it is often associated with joint pain (arthralgia), sometimes the leg may feel tired and fatigued with or without overt pain. There are several types of arthritis with the two most common being osteoarthritis (OA) and rheumatoid arthritis (RA).
Osteoarthritis is the most common type of arthritis, although there is typically no inflammation of the joint. Instead there is breakdown of the joint cartilage which is more common in the elderly. Rheumatoid arthritis is an autoimmune condition where the body’s immune system attacks the small joints thereby causing inflammation. Other types and causes include gouty arthritis, traumatic arthritis and septic arthritis.
Problems with the nerves supplying the legs can also give rise to sensations that may be described as tiredness of the legs. Nerve compression is one of the common conditions affecting the legs. Sciatica is one such condition where the sciatic nerve that emanates from the lower back becomes compressed. This nerve runs does the legs and causes pain, tingling, numbness and leg weakness.
These various conditions are referred to as peripheral neuropathy and may occur due to a host of different causes and mechsnisms. In more severe nerve conditions, the nerves may become damaged or even destroyed. Multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease) are some of the more severe conditions.
Most of the common bone conditions either present with little to no symptoms or with intense symptoms like bone pain. However, it is worth taking note of some of the less common bone conditions such as osteomalacia and osteopetrosis (not to be mistaken with osteoporosis). A severe condition that could be responsible is bone cancer, especially in the early stages before pain sets in.