Muscular teen boys are likely to live longer than their 'not so fit' peers, a new study has found.
The effect of poor muscular fitness in young men is similar to well established risk factors for early death, such as obesity and high blood pressure, researchers say.
Swedish experts, who tracked more than a million teenage boys for 24 years, found those with low muscle strength, weaker leg, arm muscles are at higher risk of early death.
Researchers behind the British Medical Journal study believe muscle strength reflects general fitness, which would explain the link.
Experts stress the findings do not mean muscle building makes you live longer, however, the link between early death and muscle power remained in the study.
During the study, thin and fat men alike fared worse in terms of life expectancy if they had weaker than average muscles, while more burly men had better survival odds even if they were overweight.
As many as 26,145 (2.3%) of the men died over the course of the study. The leading single cause of death was accidental injury, followed by suicide, cancer, heart disease and stroke.
The teenagers who scored above average on muscular strength at the start of the study had a 20-35% lower risk of early death from any cause and also from cardiovascular diseases.
They also had a 20-30% lower risk of early death from suicide and were up to 65% less likely to have any psychiatric diagnosis, such as schizophrenia or depression.
In comparison, the 16 to 19-year-olds with the lowest level of muscular strength had the highest risk of dying before they reached their mid-50s.