How quickly can muscle be lost?
Some research suggests that you can start to lose muscle in as quickly as one week of inactivity - as much as 2 pounds if you are fully immobilized (3). And another study suggests your muscle size can decrease by about 11% after ten days without exercise, even when you aren't bed ridden (4).
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.
If you take a week or two away from the gym, you probably won't lose strength or muscle mass. If you take more than three weeks off, you'll lose at least a little bit of strength and muscle, but you'll regain it quickly when you start lifting again.
Athletes can start to lose their muscle strength in about three weeks if they're not working out, according to a 2013 study. Athletes typically lose less overall muscle strength during a break than nonathletes.
In certain cases, muscle can atrophy alarmingly fast. Bedrest, for example can cause a 12 percent loss of muscle strength per week. And exposure to zero-gravity can result in a 20 percent loss of muscle mass after only five to 11 days. But those are extreme cases — strength and muscle loss doesn't happen all at once.
Although you start losing muscle mass after 72 hours, you probably won't notice any losses until you've gone 3–4 weeks without training. One small study found that trained men could take three weeks off from exercise without any noticeable muscle loss.
Some athletes see a loss of about 6% muscle density after three weeks. Some power lifters see losses of as much as 35% after seven months. Young women who trained for seven weeks and gained two pounds of muscle mass, lost nearly all of it after detraining for seven weeks.
In the context of working out, muscle memory describes the phenomenon of muscle fibers regaining size and strength faster than gaining them in the first place. In other words, it refers to the fact that it's much easier to regain lost muscle and strength than it is to build muscle and strength from scratch.
In general, just two weeks of detraining can lead to significant decline in physical fitness. A study from the Journal of Applied Physiology concluded that just a fourteen-day break significantly reduces cardiovascular endurance, lean muscle mass, and insulin sensitivity.
Because nothing keeps you on track better than results. That said, there is a limit to how fast you can lose fat without losing muscle. Other researchers have suggested that the maximum weekly rate of weight loss should be 0.5 to 1% of body weight per week, which is about how fast these athletes lost weight.
Can you lose a pound of muscle in a day?
To be exact your body burns 6 calories per hour per pound of muscle and 2 calories per hour per pound of fat. On average, 1lb of muscle will burn (within 24 hours) an extra 96 extra calories in comparison to fat tissue.
SUMMARY There's no evidence that fasting causes more muscle loss than conventional calorie restriction. In fact, studies demonstrate that intermittent fasting may help you maintain muscle mass while dieting.
That is entirely up to you, but I'd recommend that any extend break be for at least a month. That should be enough time to let your body rest and allow minor injuries to heal. It's also not so long that you'll struggle to resume your workout schedule again.
Recent clinical evidence bears out the fact that repeated short-term fasting does not cause muscle loss. In a 2010 study of alternate daily fasting, patients were able to lose significant fat mass with no change in lean mass.
Conclusions: A 10 day fast appears safe in healthy humans. Protein loss occurs in early fast but decreases as ketogenesis increases. Fasting combined with physical activity does not negatively impact muscle function.
Neurogenic atrophy is the most severe type of muscle atrophy. It can be from an injury to, or disease of a nerve that connects to the muscle. This type of muscle atrophy tends to occur more suddenly than physiologic atrophy.