The research involving 5,772 Scottish men for up to 35 years showed that those who drank between eight and 14 units a week were more likely to be admitted to hospital than those who drank fewer units or nothing.
It is equivalent to four pints of beer, eight shots of spirits or eight small glasses of wine.
The researchers revealed that as the average alcohol intake increased, the risk of being admitted to hospital and the length of stay subsequently increased.
It showed that overall effects of alcohol were substantial.
"This study confirms that people exceeding the recommended limits for alcohol are adding to the burden on the NHS through longer hospital stays," the BBC quoted Professor Ian Gilmore, president of the Royal College of Physicians, as saying
"It is vital that government and health professionals join forces to reinforce the risks of alcohol misuse across a wide range of medical complications," he added.
The study has been published in the Journal of Epidemiology and Community Health.