It takes just two weeks of physical inactivity for those who are physically fit to lose a significant amount of their muscle strength, new research indicates.
In that relatively short period of time, young people lose about 30 percent 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 percent of their strength.
The more muscle a person has, the more they will lose if they are sidelined by an injury, illness or vacation, the Danish study found.