Researchers at the Cleveland Clinic in the US have found that better cardiorespiratory fitness leads to better longevity, regardless of age, with no limit on the positive effects of aerobic fitness.

Cardiorespiratory fitness is the ability of the circulatory and respiratory systems to supply oxygen to skeletal muscles during sustained physical activity. The study, published in the journal JAMA Network Open, found that increased cardiorespiratory fitness was directly associated with reduced long-term mortality particularly in older patients, aged 70 and above, and among those with hypertension. "Aerobic fitness is something that most patients can control. And we found in our study there is no limit to how much exercise is too much. Everyone should be encouraged to achieve and maintain high fitness levels," said Wael Jaber, cardiologist at the institute. 

Researchers from the varsity examined 1,22,007 participants who underwent exercise treadmill testing to measure all-cause mortality -- all of the deaths occurring in a population, relating to the benefits of exercise and fitness. Participants were broken up into five performance groups - elite, high, above average, below average and low. 

Elite performers were defined as having aerobic fitness by age and gender, and demonstrated fitness levels comparable to endurance athletes. When the subgroups were analysed by age, the survival benefit of elite versus high performance was the most notable in older patients, the findings revealed. 

Results showed that among respondents above 70, elite performers had a nearly 30 per cent reduced risk of mortality compared to high performers. For those patients with hypertension, the elite performers again showed a nearly 30 per cent reduction in all-cause mortality compared to high performers. 

The risk associated with poor cardiorespiratory fitness was compared to or even exceeded traditional risk factors, such as cardiovascular disease, diabetes and smoking, according to the study. However, according to the study, individual patients should always check with their healthcare provider before starting an exercise programme.