After two weeks of not training, significant reductions in fitness begin to occur and you'll have about 2-8 weeks of training (depending on the length of inactivity) ahead of you to get back to your previous level of fitness.
While the exact timeframe can vary from person to person, research suggests that you can start losing stamina and endurance within just a couple of weeks of inactivity. Generally, after about two weeks without running, your cardiovascular fitness may begin to decline significantly.
A two-week break, especially due to illness, won't derail your progress. Think of it as a recovery period that could even prevent overtraining or burnout. Your body is designed to adapt, and with consistent effort, you'll return to your normal strength and performance in no time.
You can actually lose your cardio endurance and muscle strength with two weeks of complete rest, says Milton. That doesn't mean two weeks out you'll have lost all your gains, but this is when you can expect the decline to start, she says.
If you miss two weeks of quality runs, return with a slightly more conservative approach. Run 1-2 easy days before moving back into normal mileage. The most important step is to listen to your body. See how your legs respond to easy runs before deciding when to attempt a workout.
While many runners only take 1 week off running, we see in our physical therapy clinic that taking at least 2 weeks off from running results in fewer injuries and stronger runners during the subsequent training season.
In the first ten days to two weeks of inactivity/de-training, there is a measurable loss in cardiovascular fitness, but even this level of decrease is only about 2-3% drop in values such as VO2 Max, MAP (maximum aerobic power), or FTP (functional threshold power).
You might notice your performance slip, too: “Speed, endurance, and strength can decrease by 25 to 30 percent within two to three weeks,” says Weiss.
5 days-3 weeks: Some changes occur beyond about five days which, over time, start to impact fitness. Your blood plasma volume starts to decrease, which leads to a decrease in cardiac output – in short, less oxygenated blood to your muscles.
In short, most of the research shows muscle power declines significantly slower than metabolic factors. What does this mean? After 7-10 days of not running, you will lose some muscle power and coordination, but not enough to totally derail your goals.
According to Jesse Shaw, D.O., associate professor of sports medicine at the University of Western States, this is typical for the general population, too: It usually takes between three and four weeks to start noticing a decrease in strength performance with a complete cessation of activity.
Generally, it takes anywhere from two to 12 weeks to regain cardiovascular endurance and muscle strength and feel like you're back at your previous level of fitness.
'Muscle strength is preserved initially, but after two to four weeks, you'll see losses in strength and muscle size,' says Dr Graeme Close, reader in Sports Nutrition and Exercise Metabolism at Liverpool St John Moores University.
As muscle cells get smaller, fat cells tend to get bigger. After all, the muscles aren't working hard enough to burn away calories. This can lead to weight gain as soon as 14 days (or earlier) once you stop exercising, according to Men's Journal.
Start Slowly: Begin with short runs of 10–15 minutes, 2–3 times a week. Don't stress over pace or distance; the aim is to rebuild your running foundation and form. Build Gradually: Increase your running time by 1–2 minutes per session, adhering to a training schedule that doesn't increase by more than 10% per week.
Build for 3 Weeks, Rest for a Week
Furst recommends increasing mileage for three weeks, and then taking the fourth week “down,” by running a lower weekly mileage and more easier runs than the week before. (You'll see this built into most Runner's World+ training plans.)
There is no age limit to running.
We each age differently, and some of us have to deal with different issues. To be able to continue running regularly in your seventies and enjoy it, you have to be realistic about your capacity.
Immediate Benefits (Weeks 1-2): When you begin incorporating cardio exercises into your routine, you may notice some immediate benefits. These can include increased energy levels, improved mood, and better sleep.
If it has been longer, you may not want to rush back to several-mile runs. Mix running with walking, take time building up strength in unused muscles, and use a few tricks to motivate and reward yourself. It can take about two months for a new behavior to become automatic. Once it does, it also becomes less taxing.
Short term “breaks” from the gym (1-2 weeks) are not the end all be all of your hard-earned progress. But, be sure to keep your diet high in protein and feed your body what it needs to help you hold onto that muscle!
Once you hit the 10 day mark, you are starting to lose endurance, increase body fat and then at about 14 days mitochondrial density and enzyme activity declines. Aerobic benefits really decline at that 2 week mark and becomes more impaired with prolonged detraining.
In 2 weeks, most people can lose between 2-4 pounds (0.9-1.8kg) if they're sticking to a healthy eating plan and exercising regularly. This might not seem like much, but it's the best way to lose weight without causing harm to your body. Remember that small, steady progress leads to long-term success.