There are lots of reasons you can fall "out of shape." From injuries to waning motivation, it's natural for your fitness to ebb and flow. The good news is, whether you were always an athlete or could never seem to stick to a workout routine, there are some tried and true methods to help you get fit again.
Physiologically speaking, being physically fit entails a holistic look at several factors: cardiorespiratory fitness, muscular strength, mobility, (within that, flexibility and range of motion), and neuromuscular control (i.e. balance and agility), explains Heather Milton, a board-certified clinical exercise physiologist at NYU Langone's Sports Performance Center.
Anecdotally, being physically fit will look and feel different for everyone, but can often mean you have good energy, feel strong, are able to perform daily functions without pain, have mental clarity, and generally just feel healthy and happy.
This subjectivity can mean getting back in shape will include different goals for different people. "Does being 'fit' mean that you're able to walk all day for your job and still have energy to play with your kids, or does it mean that you're able to crush a new mountain biking trail without injury?" says Jacqueline Crockford, an ACE-certified personal trainer. Understanding your reason why will help you maintain the motivation needed to support your goals long term.
The good news is there are steps most anyone can follow to improve their overall fitness. Here's what to expect.
To understand how to regain fitness efficiently, it helps to know how fast your initial results can go away. 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. Generally, cardio endurance depletes at a slower rate than muscular strength and endurance, which has a fairly rapid decline when you stop training, adds Crockford.
A loss of physical fitness can cause a rise in blood pressure, decrease in blood oxygen levels, decreased neural-muscular efficiency and heart strength, reduced lung capacity, and even a change in your resting heart rate, explains Milton.
Age is also an important factor to consider, says Crockford. Maximal oxygen uptake (or VO2max), muscle strength and mass, and flexibility are all naturally reduced with aging, while total body mass and fat mass increase, according to a 2009 study published in the European Review of Aging and Physical Activity.
On average, if you are strictly following an evidence-based, strategically designed fitness program -- meaning you have done your homework and are adhering to a specific plan -- you can expect to regain your fitness in 16 weeks, says Milton. Muscular strength can begin to improve in four to six weeks with noticeable results in 12 weeks. Improvements in your cardio also follow a linear pattern, with small changes progressing bit by bit over time, she says.
"However, that's in a vacuum," caveats Milton. This does not account for lifestyle factors such as changes in weight, diet, health conditions, or hydration, for example -- all of which can drastically impact how long it takes you to get fit again.
"The rate at which someone regains their fitness levels, in both muscular and cardiorespiratory measures, is dependent on several factors including the programming, previous fitness levels and exercise experience, as well as age," says Crockford. How long you took off from exercise matters, too, says Milton. If it's been a few weeks or even a few months, that's a big difference than a few years. "If it's less than a year, you're starting back at maybe 50 percent of where you left off and slowly building back from there," she says.
The first step is setting a clear and, ideally, measurable goal. Simply saying you want to "get back in shape" could lead to a haphazard approach to training that will ultimately take you longer to achieve your goals -- if you don't get frustrated and bail along the way, says Milton.
The most important thing to keep in mind when getting back into a workout routine is to pace yourself. This is especially true if you have been largely inactive (rather than just choosing lower-intensity modalities), are returning from an injury, or are older.
Older adults have more years of experience with training under their belt, so they may be smarter about easing into a renewed routine, says Milton, but conversely, if you'll also want to avoid doing the same grueling workouts you did when you were younger. Bodies change over time, and it's ok if your version of fit looks different in your 40s then it did in your 20s, she says.
A steady progression in difficulty will ensure you stay on track while avoiding injury or burnout, says Milton. Cardio exercise can be increased by the total volume of training, meaning if you have been successfully running three hours every week, you can increase the length of total weekly time spent running. Progressing strength-based training can look like more reps using the same weight or grabbing a higher weight while doing the same reps, adds Milton. Max-rep bodyweight tests -- think: how many push-ups you can do in a minute -- are a good universal strength-building tactic, too. The bottom line is you can get fit again, but it likely won't happen overnight. Small, smart steps over time will lead to the results you're after, so practicing patience is a necessary component.