Two Weeks of Inactivity Enough to Weaken Your Muscles

Lisa Franchi July 13, 2015

Even though you are physically fit, it only takes two weeks of inactivity to lose a significant amount of your muscle strength, according to new research. In the study, young people lose about 30 per cent of their muscle strength, leaving them as strong as someone decades older.

Meanwhile, active older people who become sedentary for a couple weeks lose about 25 per cent of their strength.

The study, carried out by the researchers from University of Copenhagen in Denmark, found that the more muscle a person has, the more they will lose if they suffer an injury or illness or took vacation.

"Our experiments reveal that inactivity affects the muscular strength in young and older men equally. Having had one leg immobilized for two weeks, young people lose up to a third of their muscular strength, while older people lose approximately one-fourth. A young man who is immobilized for two weeks loses muscular strength in his leg equivalent to aging by 40 or 50 years," says Andreas Vigelsoe from the Centre for Healthy Aging and the Department of Biomedical Sciences at the University of Copenhagen in Denmark.

While total muscle mass normally declines with age, in the study, two weeks of not moving at all, the young male participants lost 17 ounces of muscle, on average.

Meanwhile, the older participants lost about nine ounces. However, all of the men lost physical fitness while their leg was immobilised.

"The more muscle mass you have, the more you’ll lose. Which means that if you’re fit and become injured, you’ll most likely lose more muscle mass than someone who is unfit, over the same period of time," said Martin Gram, another researcher at the Centre, said in the news release.

"But even though older people lose less muscle mass and their level of fitness is reduced slightly less than in young people, the loss of muscle mass is presumably more critical for older people, because it is likely to have a greater impact on their general health and quality of life,"

More interestingly, even working out (through biking) for three to four times a week for six weeks, the muscle strength of the participants did not fully recover.

According to the researchers, a more intense exercise such as cycling may be sufficient to help people regain lost muscle mass and restore their former fitness level. Moreover, they say it needs three times the amount of time you were inactive to get your muscle mass back.

The findings were published in the Journal of Rehabilitation Medicine.

Source of this article: Muscle Strength Fades After Just Two Weeks of Inactivity