The domino effect
You can’t have the muscle mass of a much older person without seeing declines in other bodily systems, creating a domino effect that pushes your body into further disrepair. When you have less muscle, your cardiac output is reduced. Because your cardiac output is reduced, your aerobic system is affected, so you have less energy. Blood pressure levels rise slightly. Your sense of balance isn’t as good, and even your brain doesn’t work as well.
“Brain-derived neurotrophic factor (BDNF), a major brain protein, is decreased, which may lead to an increased chance of depression,” Weiss says. “Dopamine levels drop, which may stimulate anxiety, depression and other mood/behavior shifts, as well as cause a sense of tiredness and fatigue that reduces the impetus to exercise.”
In other words, the less you exercise, the less you want to exercise. You’ll find it hard to motivate yourself to work out, and if you try, you’ll be more easily winded, and basic exercises will require more energy. That’s how two sedentary weeks turn into three or four, and your physical health really tumbles off a cliff.
Two months: Things are getting flabby
Now is when you’ll start looking like the “Before” picture in a diet supplement advertisement. “After six to eight weeks, the fat mass can get greater than lean mass, causing the waistline to get bigger,” according to Weiss. Only two months! “Men usually get the increase in fat in the abdomen, while women add more mass in the lower body.”
Within a month or two of inactivity, Mrozek says, all the gains you’ve achieved through a consistent exercise routine are lost. And just like that, you fall back in with the ranks of the physically unfit.