A combination of talk therapy and exercise training may help people who suffer lingering fatigue after a stroke, a new study suggests.

People commonly feel worn out in the months, or even years, after having a stroke. In studies, anywhere from 38 percent to 73 percent of stroke survivors have reported problems with persistent fatigue.

The exact reasons aren't clear, and experts suspect that different factors are at play for different people. For some, brain damage from the stroke may be to blame, while for others depression, physical limitations or low fitness levels might be involved.

Certain stroke treatments, like physical therapy, may help some people with fatigue.

But partly because researchers aren't sure of the root cause, there are no standard therapies aimed specifically at post-stroke fatigue, said Aglaia Zedlitz, lead researcher on the new study.

"Post-stroke fatigue has long been a neglected issue in healthcare and science, although many patients suffer severely from the fatigue," Zedlitz told Reuters Health in an email.

For their study, she and her colleagues at Radboud University Nijmegen in the Netherlands tested two therapies: cognitive therapy and "graded activity training" -- which included walking on a treadmill, strength training and exercise "homework."

The researchers recruited 83 patients who were suffering from chronic fatigue an average of four years after having a stroke.

Half were randomly assigned to 12 weeks of cognitive therapy alone, and half had cognitive therapy plus the exercise training.

The cognitive therapy, done in weekly small-group sessions, focused on tactics for easing fatigue in day-to-day life.

"They learn what fatigue is," Zedlitz explained, "that it is a common (problem) after stroke, what is fatiguing to them personally, and what they can then do about it in their own life."

After 12 weeks, the study found, 58 percent of patients receiving both therapies had a "clinically relevant" improvement in their fatigue, based on questionnaires. That compared with 24 percent of patients who'd had only cognitive therapy.

A clinically relevant improvement meant that patients had noticeable changes in their daily activities, Zedlitz said.

The findings, reported in the journal Stroke, suggest that a combination of cognitive therapy and exercise might help post-stroke fatigue.

But one shortcoming of the study is that it had no "control" group of patients who received neither therapy.

"Since we did not include a control condition of patients receiving no therapy at all -- or better yet, a 'sham' condition -- we cannot ascribe the effects found to the therapy with utmost certainty," Zedlitz said.

However, she added, past studies have shown that post-stroke fatigue is stubbornly persistent, making it unlikely that so many patients would spontaneously improve during the 12-week study.

The combination treatment is starting to become available in the Netherlands, according to Zedlitz. But more research is still needed, she said.

So far, the researchers have studied only stroke survivors who are in relatively good shape. None, Zedlitz said, have had more than mild cognitive impairments, and all have been able to walk without help.

She also pointed out that the patients in this study had typically suffered a stroke several years earlier. Studies need to see whether intervening sooner could be more effective, according to Zedlitz.

"As fatigue has been found to have a negative impact on rehabilitation outcome," she said "this could even help to improve rehabilitation in general."