Being able to walk up four flights of stairs without stopping for a break is key to avoiding an early death, researchers say.
Spanish scientists tested the theory on nearly 13,000 people who were battling or suspected to have coronary artery disease.
They found those who struggled were three times more likely to die from heart disease and faced twice the risk of dying from cancer.
The researchers claim their results provide further evidence of the benefits of exercise and being fit on health and longevity.
Researchers from the University Hospital Coruña in Galicia analysed people with diagnosed or suspected coronary artery disease (CAD).
The study was presented at the 2018 EuroEcho-Imaging conference in Milan, and led by the cardiologist Dr Jesús Peteiro.
Participants were asked to walk or run on a treadmill, gradually increasing the intensity until they reached the point of exhaustion.
While exercising, they were hooked up to echocardiogram, which uses sound waves to create moving pictures of the heart that show its size and shape.
The test, which has been used for 30 years and is a recognised method of diagnosing CAD, also shows how well a patient’s chambers and valves are working.
The energy the participants exerted was measured in metabolic equivalents (METs). One MET is the rate of energy expenditure, or oxygen use, while sitting quietly.
Light activities, such as standing or walking slowly, use less than three METs, according to the researchers.
While moderate activities, such as brisk walking, use three-to-six METs, and vigorous activities, such as jogging or playing football, use more than six METs.
Good functional capacity was defined as being able to achieve ten METs during the treadmill test before becoming breathless.
The participants were divided into two groups – good functional capacity or poor functional capacity of less than ten METs.
During the five-year follow-up period, 1,253 of the participants died from cardiovascular disease, 670 from cancer and 650 from other causes.
Each MET achieved during the test was associated with a nine per cent lower risk of dying from cardiovascular disease or cancer.
Dr Peteiro also revealed there was a four per cent lower risk of passing away from another cause for each MET achieved.
The risk of dying from cardiovascular disease was 3.2 per cent among the participants with poor functional capacity and 1.2 per cent in those with good capacity.
Non-cardiovascular and non-cancer deaths were also nearly three-fold higher in those with poor compared to good functional capacity, at 1.7 per cent versus 0.6 per cent.
Cancer deaths were almost twice as high in the participants with poor compared to good functional capacity at 1.5 per cent versus 0.8 per cent.
‘Our results provide further evidence of the benefits of exercise and being fit on health and longevity,’ Dr Peteiro said.
‘In addition to keeping body weight down, physical activity has positive effects on blood pressure and lipids, reduces inflammation, and improves the body’s immune response to tumours.’
As the researchers expected, the echo imaging part of the experiment helped to predict those at risk of cardiovascular death but not fatalities caused by cancer or other conditions.
Dr Peteiro stressed people do not need to undergo exercise echo tests to check their fitness levels.
‘There are much cheaper ways to estimate if you could achieve ten METs on the treadmill test,’ he said.
‘If you can walk very fast up three floors of stairs without stopping, or fast up four floors without stopping, you have good functional capacity.
‘If not, it’s a good indication that you need more exercise.’
The European Society of Cardiology recommends at least 150 minutes a week of moderate aerobic physical activity or 75 minutes a week of vigorous aerobic physical activity, or a combination of the two intensities.