That 98-pound weakling may want to hit the gym if he hopes to live a long life. A study published in the British Medical Journal (2012; 345: e7279) suggests that male adolescents without much muscle strength may earn early death in adulthood.
The large study included 1,142,599 Swedish males aged 16–19 who were followed for 24 years. The primary focus was to determine whether muscular strength had any impact on mortality rates. Premature death in this study was considered death before 55.
Researchers tested subjects’ strength levels with three exercises: knee extension, handgrip and elbow flexion. These tests were considered highly reliable, based on their success in previous studies. Scientists also measured participants’ blood pressure, height and weight.
During the follow-up period, 26,145 subjects died; cause of death was available for 22,883. Subjects died from unintentional accidents (5,921; 25.9%); suicide (5,100; 22.3%); cancer (3,425; 14.9%); coronary heart disease (1,254; 5.5%); stroke (526; 2.3%); and other causes (6,657; 29.1%).
“Higher levels of muscular strength were significantly associated with lower risk of all cause mortality,” the study authors stated. “The association was stronger for knee extension and handgrip strength than for elbow flexion strength.”
Blood pressure and BMI were connected to premature mortality owing to their relationship with cardiovascular disease, the authors suggested. “The risk reduction was approximately 35% in high muscular strength groups, 60%–70% in low body mass index groups, and 35%–45% in low diastolic blood pressure groups, compared with the reference groups,” they added.
The researchers noted a 20%–30% lower risk of suicide among highly muscular individuals. They found “a monotone and inverse association between body mass index and mortality due to suicide.”
The researchers also reported that “BMI was the only significant predictor of premature mortality due to cancer, with a risk reduction of 25%–35% in participants with low BMI compared with those with high BMI.”
“This study provides strong evidence that a low level of muscular strength in late adolescence . . . is associated with all cause premature mortality to a similar extent as classic risk factors such as body mass index or blood pressure,” the authors warned. “Finally, our data suggest that low muscular strength is associated with an increased risk of mortality due to suicide, supporting the notion that physically weaker people might also be mentally more vulnerable. Low muscular strength should be considered an emerging risk factor for major causes of death in young adulthood.”