When nerves in the legs and feet are damaged from diabetes, people often have trouble on stairs, but a new report suggests exercise might help lower their risk of falling.
People with so-called diabetic peripheral neuropathy go up and down stairs more slowly and clumsily than healthy people because of weak muscles, sensory damage (loss of feeling) and poor coordination, say the authors of the report.
Resistance exercises could help these individuals build up strength and avoid future falls, they wrote in the journal Diabetes Care.
For people with diabetic peripheral neuropathy, falls "whilst walking down stairs are nearly unrecoverable," and as a result, account for a large proportion of fall-related deaths, said Joseph C. Handsaker of Manchester Metropolitan University in Manchester, UK, who led the research.
"The aim of the study was to provide potential explanations for why patients with neuropathy are at a high risk of falling during the dangerous tasks of stair ascent and descent, in the hope that by identifying why falls occur, we can then suggest solutions for how to reduce the risk of falling," Handsaker told Reuters Health.
An estimated 347 million people worldwide have diabetes, according to the World Health Organisation. About half of patients with diabetes develop peripheral neuropathy after 10 years, Handsaker said.
It's been known for a while that these patients have trouble on stairs, but the underlying reason hasn't been clear, Handsaker added.
He and his colleagues compared 21 patients with diabetic neuropathy, 21 who had only diabetes, and 21 healthy individuals as they walked up and down a custom-built staircase.
The researchers analysed the electrical activity of participants' muscle tissue to determine when the muscles were "switched on and off" and when they reached peak activation.
Overall, the patients with diabetic peripheral neuropathy were significantly slower at activating their knee and ankle muscles than the healthy group, and significantly slower at reaching peak knee-muscle activation.
"The slower speed of strength generation is the key finding in this study, with alterations to muscle activation expected to contribute to the observed reductions," said Handsaker.
For diabetics with peripheral neuropathy who'd like to strengthen their muscles and reduce their risk of falling, Handsaker suggested using isometric exercises like calf raises and knee extensions. Individuals should rapidly stretch these muscles for a second and then relax for three seconds, he said.
His paper also advises that resistance training might be helpful, such as with weight machines, free weights or calisthenics.
(Before starting to exercise, however, patients should get clearance from their doctors. As the American College of Sports Medicine advises, "Not all exercise programs are suitable for everyone, and some programs may result in injury.")
Improving the strength and response of the extensor muscles will result in faster strength generation, which should improve stability during stair ascent and descent, said Handsaker.
Dr. Michael Polydefkis, who directs the Johns Hopkins Cutaneous Nerve Laboratory and the Bayview EMG Laboratory and Diabetic Neuropathy Center, said he was glad to see a study that emphasised the effect of diabetes on people's ability to move around.
He said people recognise the devastating effects of diseases like multiple sclerosis, Parkinson's and ALS but often don't realise how much diabetic neuropathy compromises quality of life.
"Oftentimes peripheral neuropathy is not always given its due respect," said Polydefkis in a phone interview. "People don't really appreciate the impact this has on people's lives."
Polydefkis, who was not involved in the study, said his patients typically complain of pain and numbness in their feet, rather than weakness. But the study showed that falls might be related to subtle muscle problems that aren't easy to detect. He often suggests balance exercises for his patients.
Dr. Peter Dyck, who directs the Peripheral Nerve Research Laboratory at the Mayo Clinic in Rochester, Minnesota, told Reuters Health in a phone interview that the study helps confirm some of the reasons for the unsteady gait of diabetics. But Dyck, who was not involved in the study, said he wasn't convinced that exercise would help these individuals because of their sensory loss.
"I think it's a worthwhile study, it was fun to read, but I'm not sure the take-home message is quite correct," said Dyck. "The emphasis needs to be on preventing polyneuropathy by good diabetic control."