Early bicycle exercise during their stay in a hospital intensive care unit (ICU) may help some patients recover more quickly, a new study has claimed.

Researchers demonstrated that physiotherapists can safely start in-bed cycling sessions with critically ill, mechanically ventilated patients early on in their ICU stay.

"People may think that ICU patients are too sick for physical activity, but we know that if patients start in-bed cycling two weeks into their ICU stay, they will walk farther at hospital discharge," said Michelle Kho, an assistant professor at McMaster University and physiotherapist at St Joseph's Healthcare Hamilton in Canada.

"Our TryCYCLE study builds on this previous work and finds it is safe and feasible to systematically start in-bed cycling within the first four days of mechanical ventilation and continue throughout a patient's ICU stay," said Kho.

Patients who survive their ICU stay are at high risk for muscle weakness and disability and muscle atrophy and weakness starts within days of a patient's admission to the ICU.

Cycling targets the legs, especially the hip flexors, which are most vulnerable to these effects during bed rest.

By strengthening their muscles and overall health, patients may go home sooner, stronger and happier.

This not only benefits the patient, but could alleviate the high cost of critical care for the health care system.

TryCYCLE is the first of a series of studies that will determine the effects of early in-bed cycling with critically ill patients.

Over a year, Kho and her team conducted a study of 33 patients in the ICU at St Joseph's Healthcare Hamilton.

Patients were 18 years of age or older, receiving mechanical ventilation, and walking independently prior to admission to the ICU.

The treatment in the ICU was 30 minutes of supine cycling using a motorised stationary bicycle affixed to the bed, six days a week.

The researchers found that early cycling within the first four days of mechanical ventilation among patients with stable blood flow is safe and feasible. Patients started cycling within the first three days of ICU admission and cycled about 9 km on average during their ICU stay.

"Patients' abilities to cycle during critical illness exceeded our expectations," said Kho.

She added that more research is needed to determine if this early cycling with critically ill patients improves their physical function.

The research was published in the journal PLOS ONE.