Both on their own reduce the chances of people with high cholesterol dying prematurely, the study found. But together they had a significantly greater effect.
US scientists studied more than 10,000 veteran service men and women who had been diagnosed with the high cholesterol condition dyslipidaemia.
All had their fitness graded after taking part in an exercise test. Participants, who had an average age of 60, were then divided into those who were taking statin drugs and those who were not.
Over 10 years, death rates were lowest for those who were both taking statins and physically fit.
Researchers used the least fit participants who were on statins as their benchmark. Compared with this group, individuals who were both highly fit and taking statins had a 70pc reduced risk of death.
For those who were highly fit but not taking statins, the chances of dying were reduced by just under 50pc.
Death risk for the least fit individuals who were not taking the drugs was increased by 35pc.
The differences could not be explained by factors such as age, weight, ethnicity, sex, heart disease history and other drugs, said the researchers writing in the The Lancet medical journal.
Study leader Dr Peter Kokkinos said: "The fitness necessary to attain protection that is much the same or greater than that achieved by statin treatment in unfit individuals is moderate and feasible for many middle-aged and older adults through moderate intensity physical activity."
People with dyslipidaemia, or high cholesterol, should improve their fitness to at least a moderate level, he said.
"Treatment with statins is important, but better fitness improves survival significantly and is a valuable additional treatment," Dr Kokkinos added.