The importance of physical activity among older people with limited mobility has been highlighted in a new study.

According to the findings, every minute of activity may lower the risk of heart attack or coronary death in this population. In fact, the amount of activity appears to be more important than the intensity of the activity.

The US study involved 1,170 people aged between 74 and 84. All had physical limitations but were capable of walking 400 metres.

The participants were fitted with accelerometers - small devices which detected activity. A reading of fewer than 100 counts a minute was considered to be a sedentary period, 100-499 was considered activity such as light housekeeping or slow walking, while 500 or more was considered a moderate activitiy, such as faster walking.

The researchers calculated the participants' predicted 10-year risk of suffering a heart attack or coronary death based on factors such as age and blood pressure. They found that for every 25-30 minutes a person was sedentary each day, their predicted risk rose by 1%.

"The idea is that, even if you exercise for an hour in the morning, if you go and sit for eight hours the rest of the day you may have health risks that are independent of the fact you exercised. This stresses the need for regular intervals of low-level movement and to avoid sitting for excessive stretches of time," commented the study's lead author, Dr Thomas Buford, of the University of Florida.

The researchers acknowledged that while adults are recommended to engage in higher intensity activities to improve their health, this may not be realistic for older people with limited mobility, however these findings emphasise the importance of even light activity on an ongoing basis.

"In the past, much of the emphasis was placed on engaging in structured physical exercise. It is becoming increasingly evident, however, that encouraging individuals to just reduce the amount of time they spend being sedentary may have important cardiovascular benefits," Dr Buford added.

Details of these findings are published in the Journal of the American Heart Association.

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