Lack of willpower or lack of wherewithal? "Internal" and "external" barriers to changing diet and exercise in a three year follow-up of participants in a health check

The aims of this paper were to assess whether anticipated barriers to change in diet and exercise which were cited before a health check intervention were related to subsequent behaviour changes. In 1989 a health and lifestyle questionnaire was posted to 17,965 people aged 35-64 who were registered with five general practices in Bedfordshire. Taking account of non-contacts, a response rate of 80.3% was achieved and 11,090 people described their exercise and dietary habits. Those expressing an interest in changing each behaviour were asked to identify reasons why change might be difficult. Two types of barriers--"internal" and "external"--were identified. A total of 2205 respondents were invited to attend a health check in Year One and a recheck three years later and 1660 attended. In this subgroup improvement in exercise and diet was examined in relation to the participants' baseline characteristics, including the type of barriers selected. Internal barriers to change (e.g. lack of willpower, too lazy, too busy) were chosen most frequently. In a logistic regression including a range of baseline variables those who selected only internal barriers were less likely to take more exercise (OR 0.59, 95% CI 0.41, 0.86) than those who cited only external (e.g. no transport, can't afford sports facilities) or mixed barriers to changing. There was a similar but not statistically significant trend for changing diet (OR 0.78, 95% CI 0.48, 1.28). Those who are aware of external limitations may be better placed to circumvent them. Further research is needed to explore this relationship between type of barrier and behaviour change.