If workers exercised more, levels of sick leave could be cut dramatically, saving the UK economy £487m each year, a report has said.
A fitter population would boost the leisure industry
According to consultants Deloitte, only 48% of the population exercise enough to meet the government's recommended target of 150 minutes per week.
But if 70% took that amount of exercise, it would cut sick leave by 2,783,808 days a year, Deloitte said.
This would improve firms' productivity and ease the burden on the NHS.
More leisure facilities
"The benefits of a fitter population would be felt throughout the economy," said Deloitte partner Adrian Balcombe.
"A population more motivated to exercise could boost revenues for health club and leisure centre operators, employers would see increased productivity through reduced absenteeism and people would enjoy a healthier lifestyle with reduced risk of illness."
The survey of 10,000 people found that those who exercised less than the recommended 150 minutes per week took an average 3.5 sick days per year, compared to three days for those who exercised for over 150 minutes each week.
The Chief Medical Officer, Sir Liam Donaldson, has said adults should exercise for at least 30 minutes a day, five days a week.
The government has set a target of building enough facilities to ensure that by 2020, no one will be more than a 20-minute journey away from their nearest leisure centre or swimming pool.
A separate survey by the Chartered Management Institute (CMI) found that 60% of managers reported that sickness rates in their companies had increased over the last year.
However, 50% of bosses themselves said they were in "good" health, with only 8% of those questioned saying they were in poor health.
But despite this, 55% of them admitted to experiencing muscular tension, aches and pains, with the same percentage reporting sleep loss or insomnia, while 57% complained that they were constantly tired.
The average manager reported having 3.19 days of absence from work in the past year due to ill-health or injury.
Stress, respiratory problems and back pain were the main causes of absence among managers, the CMI said.
Bosses said they believed health issues were becoming more important in the workplace, given that about 35 million days are lost each year to illness and injury.
"Improving workplace health and well-being therefore not only makes common sense, it can also really make a difference," said David Williams, claims director at insurer Axa.