Technology used by slimmers to firm up flabby waistlines could provide relief for thousands of Britons blighted by poor leg circulation.
Neuromuscular electrical stimulation - or NMES - systems feature a small battery box attached by wires to electrodes mounted on adhesive pads. These transmit pulses of electricity that trigger the contraction of muscles.
A slight tickling sensation is felt on the skin, along with rapid twitching of the targeted muscles.
Devices that promise to help tone the stomach and other body areas - such as the Slendertone range - use the same principle, reports the Daily Mail.
Now new research has shown that electrical stimulation may also be more effective than compression stockings and other methods aimed at boosting blood circulation in the legs.
Trials on patients with chronic venous insufficiency (CVI) resulted in a reduction in swelling and pain symptoms.
CVI occurs when veins in the legs stop pumping blood to the heart effectively. Normally, when the leg muscles contract, they squeeze the deep veins of the legs, helping blood to circulate.
As they have to work against gravity, veins contain one-way valves that keep the blood from flowing backwards towards the foot. These valves can wear out over time, leading to blood leaking backwards and pooling in the veins of the leg.
Swelling in the legs and ankles is often the first sign. Other symptoms include varicose veins, discoloured skin, tight- feeling calves or itchy, painful legs, and pain during walking that stops with rest. Brown-coloured skin, particularly near the ankles, is another indicator.
Left untreated, CVI can lead to itching, bleeding, mobility problems and non-healing ulcers.
It is estimated that about 40 per cent of adults have some degree of varicose veins or venous insufficiency, and that one in 12 has a severe form of the condition, which becomes more common with age.
Treatments include exercises that help pump blood through the legs and build muscle, to compression stockings that squeeze the leg veins to prevent blood flowing backwards, to laser therapy and surgery to take out the damaged veins.
However, a team at Imperial College and Charing Cross Hospital have been using a non-invasive NMES device to treat CVI, with encouraging results.
The mild electrical pulses are known to activate muscle and nerve fibres, mimicking the electrical messages that come from the central nervous system to make the muscles contract.
Research shows that placing the pad of electrodes over the common peroneal nerve behind the knee, which provides sensation and triggers muscle movement to parts of the lower leg, increases blood flow.
Imperial College tested healthy volunteers to demonstrate that NMES is highly effective at boosting blood flow when compared to intermittent pneumatic compression, a therapy where an air pump and sleeve wrapped around the leg are used to increase circulation.
Results show that while compression therapy increased peak blood flow in the veins by 51 per cent, NMES improved it by 101 per cent.
The researchers then looked at its effects on patients with venous insufficiency. Patients wore the device over the peroneal nerve for four to six hours a day for six weeks and blood flow was measured on different occasions.
Results indicated that peak blood flow in the femoral vein in the leg increased by 57.7 per cent after 20 minutes.
Katherine Williams, clinical research fellow at Imperial, said: 'We have shown that NMES improves blood supply to the leg and the foot and can have significant benefits to people with circulation problems.
'These small electrical impulses activate the leg's natural blood-pumping systems, mimicking the beneficial effects of walking.
'This may be especially beneficial for those who have limited exercise tolerance.'