How Long Does it Take to Change Your Body After Working Out?

Are we there yet? That's not just a question asked by kids on a family road trip — it's also the plaintive cry of many a new exerciser in the gym, wondering how long it's going to take to start to see noticeable changes from the hard work they're putting in.

Even a handful of workouts can create a noticeable improvement in your cardiovascular fitness. Consider a small study published in the July 2018 issue of the ​International Journal of Environmental Research and Public Health​. The study involved 13 physically inactive subjects who tackled a program of high-intensity interval training. Researchers reported that they showed significant improvement in heart rate measurements by the end of the two-week testing period.

That's right — researchers found significant improvement in just two weeks. They were measuring heart rate variability, which might not be as obvious a gauge of fitness outside the clinical setting, but the fact remains that the subjects' bodies had already shown a positive, significant adaptation to aerobic exercise within just two weeks of working out.

Results outside that clinical setting may vary, depending on how much work you put in and at what intensity. But the important takeaway here is that every workout counts toward getting that exercise response from your body.

What about the types of improvements you can notice yourself? You might not immediately snap into an ultra-marathon level of fitness — because nobody does that immediately, it takes time — but anecdotally, many exercisers report that doing the same workout starts to feel easier within a couple of weeks.

In the research setting, many studies seeking proof of clinically significant changes run for at least eight weeks — about two months. But the gains you can make in a few weeks are significant. Consider another small study, published in a February 2013 issue of ​Perceptual Motor Skills​.

That study lasted for 12 weeks of intermittent sprinting workouts. At the end of the study period, the 38 participants showed a 15 percent increase in aerobic power — a massive gain when you imagine your favorite aerobic activities suddenly becoming 15 percent easier.

​Read more:​ 5 Cardio Workouts If Running Isn't Your Thing

Another study, published in a December 2017 issue of the ​Journal of Sport and Health Science​, studied subjects with overweight and obesity over a notably longer time frame — 24 weeks — and gauged which methods worked to improve their cardiovascular fitness.

Ultimately, the researchers concluded that all methods (strength training, endurance training, the two combined, or simple physical activity recommendations like those issued by the Department of Health and Human Services) were all effective.

The takeaway message here is simple: The effort of getting moving, and continuing, matters more for your health than the specifics of how you do it. So feel free to choose a type of exercise that you enjoy for its own sake, because you're more likely to keep that up over the long term.

You might just be impressed — and surprised — by how much progress you make when you first step into the weight room. As Len Kravitz, Ph.D., an exercise physiologist with the University of New Mexico, explains in his article, those immediate strength gains you experience in the first few weeks of lifting are usually related to neural adaptations, as your body trains your muscles to respond efficiently to this new stimulus.

Kravitz also explains that real long-term gains in muscle size and strength (as opposed to a short-term pump) generally take more than 16 workouts to achieve. If you're strength-training twice a week, that works out to about eight weeks. And that is, by no coincidence, the typical minimum length of time for clinical studies seeking proof of gains in muscular size, strength or endurance.

So go ahead and ride the wave of those early gains from weight training — but don't stop there, because if you keep working out diligently and challenging your body enough that it must adapt to the new stimulus, even more significant gains are coming your way in as little as two months.

​Read more:​ Strength Training at Home: 5 Workouts for Every Fitness Level

What if weight loss is your primary goal? It's tempting to aim for whatever program offers the fastest, most dramatic results. But if you want to ​keep​ the weight off, it's better to think in the long term. As the Centers for Disease Control and Prevention points out, a gradual, steady weight loss rate of 1 to 2 pounds per week makes it easier to keep that weight off.

With that said, you might notice faster weight loss at the very beginning of your journey, as your body sheds extra water weight it held onto during a period of inactivity.

Even though the slow-and-steady approach to weight loss can take more time than the initial crash of a fad diet, that steady weight loss will yield better final results than the constant up-and-down yo-yo effect of unsustainable weight loss methods, when you lose the weight only to gain it back again.

Even if that steady rate of weight loss seems like it puts you at the start of a discouragingly long road, take heart: According to the Obesity Action Coalition, losing just 5 to 10 percent of your body weight can have immediate, positive impacts on your health — from decreasing overall inflammation to improving your heart health, reducing your risk of many chronic conditions and making any conditions that you might already have easier to manage.

What's the ultimate takeaway message? Every workout does something positive for your body, and in as little as two weeks of working out, results can become evident in your heart health.

If you're looking for more traditional gym results, one month of weight training (or less) can produce notable gains in strength as your body adapts to the new exercises you're challenging it with; sticking with it for even one more month after that gives your body a chance to demonstrate truly significant gains in strength and endurance.

By the same token, a month in the gym with an appropriate weight loss program that combines both diet and exercise can provide a steady weight loss of 4 to 8 pounds. Suddenly, that loss of 1 to 2 pounds per week doesn't sound so small, does it? The key is that losing weight this way makes it easier for you to keep it off, which means you can enjoy the fruits of your labor for a long time to come.