A recent study has shown that if you suffer from a lung condition such as COPD then you are at a much higher risk to suffer from falls, especially if have other medical conditions, have already taken a tumble or have a long history of smoking.

Past research has already linked COPD to an increased risk of imbalance, muscle weakness, thinning bones and blackouts. COPD alone accounts for 5% deaths globally and falls are also a major public health problem, accounting for more unintended deaths and injuries each year than any other cause (except traffic accidents).
Most falls in the study occurred indoors, often when people were standing and using their upper body at the same time, with loss of balance the most commonly reported cause. It was found that people had more than twice the risk of falling if they suffered from additional medical problems and more than triple if they already had a fall in the previous year. The findings add to growing body of evidence highlighting the increased fall risk faced by COPD patients.
In another study it was also noted that those patients who used supplemental oxygen regularly were at a reduced risk of falls. This is probably due to the fact that oxygen levels are increased in the blood stream due to the use of supplemental oxygen and that the problems such as weakness and imbalance are reduced.
Just one fall especially in the more elderly of patients can result in anything from a bruise to a hip replacement and from an unnecessary trip to the GP or a long-term stay in hospital. Having an injury when you have difficulty breathing only adds to the severity of the injury and the recovery process and could hamper your progress and increase the severity of your condition and lessen your quality of life. COPD patients need to be aware of their increased risk of falling and injuring themselves and take precautions. If you are prescribed oxygen then ensure you use it as regularly as required and as prescribed. There are workouts designed to help improve balance and stability which can help to minimize the risk. Adjust your home and activities to reduce the likelihood of a fall; not using stairs as often, moving objects to lower heights etc.

References: http://www.reuters.co